1/**@page RN9 Release notes for SCIP 9
3@section RN920 SCIP 9.2.0
4*************************
9- added check for absolute and relative gap limits at end of synchronization in concurrent solving mode, in order to terminate earlier;
10 note that if the concurrent solve is stopped due to a gap limit, the "winner" solver will have an interrupted solution status and
11 its primal and dual bounds may not be the best possible ones (use SCIPgetConcurrentPrimalbound() and SCIPgetConcurrentDualbound() instead)
12- parse pseudoboolean constraint from CIP format (and add linear-"and"-reformulation)
14Performance improvements
15------------------------
17- reoptimization now also stores propagations from propagators if reoptimization/saveconsprop is enabled;
18 the parameter will be renamed to reoptimization/saveprop in a next major release
19- imposed stricter limits on the size of disconnected components which may be solved separately during presolve
20- use individual slack variables also for constraints indicated by a common binary variable to use tighter formulation by default
21- when computing symmetries using Nauty, iteration limits are now available to terminate Nauty early
26- Benders' decomposition subproblems that are always infeasible are correctly handled and the complete problem is declared infeasible
27- skip linear constraint propagation if the residual activity bound cancels the side precision
28- correct bound tracking to make the evaluation of primal-dual-integrals work
29- skip aggregations on fixed variables in milp presolver to avoid errors for earlier versions of PaPILO
30- use indices of negation counterparts and accept fixings when ordering and-resultants of pseudoboolean constraints
31- update locks on model variables before removing pseudoboolean constraints in presolve
32- reformulate soft pseudoboolean constraints with linear constraints if the indicator decomposition is disabled
33- add workaround for recent HiGHS versions resetting the model status when changing the presolve option after a solve
34- avoid hashmap key error in removal of doubletons and singletons in dual presolve of setppc constraints by updating constraints and corresponding hashmaps after each multi-aggregation
41- added SCIPtpiIsAvailable() to check whether a working task processing interface is available (TPI != none)
42- added SCIPtpiGetLibraryName() and SCIPtpiGetLibraryDesc()
43- SCIPdelCons() can now also be called in SCIP_STAGE_TRANSFORMED
44- added SCIPstrcasecmp() and SCIPstrncasecmp() for case-insensitive string comparison
45- added SCIPbendersSubproblemsAreInfeasible() to return if at least one subproblem has been identified as being
46 infeasible prior to performing any variable fixing
50- presolving/milp/abortfacexhaustive to control the abort threshold for exhaustive presolving in PAPILO
51- presolving/milp/abortfacmedium to control the abort threshold for medium presolving in PAPILO
52- presolving/milp/abortfacfast to control the abort threshold for fast presolving in PAPILO
53- constraints/components/maxcompweight to determine the maximum weight for a disconnected component that is solved during presolve
54- constraints/components/contfactor counts the contributing factor of a single continuous variables with respect to the weight limit specified by constraints/components/maxcompweight
55- constraints/indicator/usesameslackvar to decide whether the same slack variable should be used for indicators constraints with common binary variable
56- propagating/symmetry/nautymaxncells and propagating/symmetry/nautymaxnnodes to set iteration limits in Nauty (only available if build with SYM=nauty or SYM=snauty)
60- presolving/milp/threads is now only available if PaPILO is built with TBB
61- changed default of numerics/recomputefac to 1e+6 to aim at relative epsilon precision
68- attempted to fix detection of CPLEX library on macOS and Windows systems
73- added parameter FILTER for tests/Makefile to run only tests with a specific pattern (ctest with -R FILTER)
78- adjusted Gurobi interface for Gurobi 12
79- reordered events: BESTSOLFOUND/NODE_FEASIBLE are now processed before the nodes are cut off and before NODE_DELETE events are processed
80- removed `#define` of `getcwd` (in case of Windows builds) in scip/def.h
81- the `#define` of `strcasecmp` and `strncasecmp` (in case of Windows builds) in scip/def.h will be removed with SCIP 10;
82 use `SCIPstr(n)casecmp()` (scip/pub_misc.h) instead
84@section RN911 SCIP 9.1.1
85*************************
90- fix bug in separator aggregation that caused incorrect terminations when for an integral objective the objective limit was set to a fractional value
91- fix bug in memory management of doublelex matrices where indices were set beyond array bounds
92- store relevance flags in consdataTightenCoefs() of cons_linear.c to avoid dropping variables unintentionally due to numerical changes
93- fix possible segmentation fault when resetting local and global bounds of original variables after abnormal termination
94- compare coefficient scales to detect parallelism to avoid integral relaxations in detectRedundantConstraints() of cons_linear.c
95- remove coefficient information from linear constraint hashes in order to compare keys with tolerances
96- fixed NULL pointer dereference in SCIPtpiGetNumThreads() of TinyCThread interface if called before SCIPtpiInit(); now returns 0 in this case
97- calling SCIPsolveConcurrent() when SCIP was compiled without a TPI now results in a plugin-not-found error
98- fixed LPI status functions of lpi_cpx if the barrier is called
99- check cuts for redundancy after scaling in cutTightenCoefs() and cutTightenCoefsQuad() of cuts.c
100- maintain definition of artificial integral variables in xor constraints to avoid invalidation of conflict constraints
101- free childless nodes only after the deactivation of the old focus path in treeSwitchPath() of tree.c
102- only normalize rows for column norm evaluations in shift-and-propagate heuristic to avoid unscaled violations
103- expression handler for absolute value computes now also a cut when one of the bounds is infinite as long as the sign of the argument is known
104- check for more data to be freed before modifying nonlinear constraints in SCIPaddExprNonlinear()
105- allow for terms with zero coefficients when checking sum in SCIPexprCheckQuadratic()
106- do not abort writing of constraints to lp/pip files (and forget to free buffer memory) when encountering unsupported nonlinear constraint
107- fixed that strings with names and descriptions of the LPI's were not null-terminated
108- fixed decision on when to enforce nonlinear constraints on relaxation solutions if integer variables are present
109- fixed reading of very long lines (>78000 characters) in FlatZinc reader
110- fixed write of strings with at least 1024 characters when compiling with MSVS 2015 (14.0) or later (still an issue with earlier MSVS, which will not be fixed)
111- keep epsilon coefficients in applyFixings() of cons_linear.c until multiples are merged to avoid loss of relevant contributions
112- fixed that some variable type changes were not accounted correctly in presolve of linear constraints
113- fix constraint sorting in setpp-orbitope upgrade in symmetry code
114- fixed that SCIPnodeGetConsProps() also counted bound changes from propagators
115- use original and-constraints of an untransformed pseudoboolean constraint when copying original problems to avert segmentation faults
116- sort and-constraints of a pseudoboolean constraint with respect to the resultant problem indices to avoid shuffled copies
117- treat pseudoboolean constraints as nonlinear constraints in OPB reader to prevent duplication mistakes
119Examples and applications
120-------------------------
122- in example Binpacking implement Farkas pricing for packings because branching can actually lead to infeasible restricted master LPs
127- allow unknown parameters to let tests pass if only optional dependencies are missing
134- fixed compilation and linking with HiGHS; to use HiGHS, cmake now requires to specify the directory containing the `highs-config.cmake` file via `-DHIGHS_DIR`
135- extended identification of Ipopt library on Windows to also look for ipopt.dll.lib, as this is used since Ipopt 3.13.0 (2019)
138@section RN910 SCIP 9.1.0
139*************************
144- added constraint handler that checks and enforces bounds on original variables which have been fixed or aggregated in the transformed problem
145- allow for implicit integer variables in xor constraints
146- implemented symmetry detection callbacks for pseudoboolean constraints
147- added option to consider enforcement of nonlinear constraints (including spatial branching) before integrality has been enforced
152- make sure that, in dual proof analysis, upgraded constraints can report their number of variables
153- check knapsack constraints as linear constraints to avoid violations based on implicit integrality
154- make sure that symmetry detection callbacks report success
155- make arithmetics in cuts.c more robust to avoid invalid scg cuts due to numerical rounding sensitivity
156- allow to copy pseudoboolean constraints even if no AND constraints are present in order to avoid a warning
157- set value for variable that is introduced to reformulate nonlinear objective function when reading .nl files with initial solution
158- fixed that multi-aggregations from PaPILO were accepted without ensuring that their bounds hold
160Examples and applications
161-------------------------
163- TSP: removed `gzstream.h/hpp` and parse gzipped files differently
170- SCIP_DECL_NLHDLRENFO takes additional parameter branchcandonly to indicate whether only branching candidates should be registered,
171 without looking for cuts or boundchanges
175- new function SCIPgetExprActivityNonlinear() to get activity of nonlinear constraint
176- new function SCIPincludeConshdlrFixedvar() to include new constraint handler that checks bounds on fixed original variables
180- limits/primal to terminate the solve as soon as the primal bound is at least as good as this value, same as limits/objectivestop (deprecated)
181- limits/dual to terminate the solve as soon as the dual bound is at least as good as this value
182- presolving/milp/internalmaxrounds to control the maximal rounds for each call of the milp presolver (PaPILO)
183- constraints/fixedvar/∗ to control the new constraint handler that checks bounds on fixed original variables
184- constraints/nonlinear/branching/mixfractional to specify minimal average pseudo cost count for discrete variables
185 at which to start considering spatial branching before branching on fractional integer variables
186 (default infinity means that integrality is always enforced before nonlinear constraints)
187- constraints/nonlinear/branching/fracweight to specify weight of fractionality of integer variables in spatial branching
189### New data structures
191- enum SCIP_Status has been extended by SCIP_STATUS_PRIMALLIMIT and SCIP_STATUS_DUALLIMIT to indicate termination at limits/primal and limits/dual respectively
196- changed the default symmetry computation package from sassy+bliss to sassy+nauty
197- bliss source is no longer included in the source tree, but can be linked as external library (https://github.com/ds4dm/Bliss)
198- cmake now automatically downloads and installs the latest release version of SoPlex from GitHub if it is not found directly
203- updated nauty to version 2.8.8
206@section RN901 SCIP 9.0.1
207*************************
212- fixed bug in detection of double lex matrices due to wrong memory allocation
213- fixed bug where parameter `limits/objectivestop` was copied to subscips in plugins which have different objectives
214- in count mode respect empty solution when problem is solved in presolving
215- fixed that SCIP may have tried to pass a negative random seed to an LP solver
216- fixed bug where conflict analysis in strong branching tried to analyze an unsuccessful LP solve
217- enable parameter limits/restarts by allowing to reach the restart limit in restartAllowed()
218- handle normalizing linear constraints in presolving with more caution to avoid numerical difficulties for integer variables with large coefficients
219- use quad precision to calculate residual activity bounds to reduce numerical errors for large variable bounds in cons_linear.c
220- in SCIPsolveProbingLP() when objective has been changed do not return cutoff due to exceeding the cutoff bound
221- set probing LP to be a relaxation only when objective has not been changed
222- declare contradicting infinities in getMinActivity() and getMaxActivity() as non-tight
223- reject farkas solution with large values to bound magnification of errors in SCIPgetFarkasProof()
224- if all variables are fixed, apply relative feasibility tolerance to avoid invalid infeasibility in applyFixings() of cons_linear.c
225- delete empty redundant knapsack and linear constraints after cleanup in SCIPmatrixCreate()
226- cleanup first constraints in SCIPcleanupConssVarbound(), SCIPcleanupConssSetppc(), and SCIPcleanupConssLogicor()
227- symmetry handling methods have not been added immediately after computing symmetries, which has been fixed
228- delay checking node limits after presolving to correctly continue up to the exceeding main node
229- simplified the objective sense assumption for the subproblems in the Lagromory separator
230- update effective root depth iteratively to avoid trapping it at a single child node
231- fixed that dualsparsify presolver did not always check do-not-multiaggregate variable flag
232- fixed bug in computing elements of orbits in orbital reduction
237- redefine isrelax to istight in cons_linear.c
244- A file cmake.log containing the changed options is written to the cmake build directory.
245- removed replacement of the settings of RelWithDebInfo
246- add compile option -ffp-contract=off or /fp:precise to enhance reproducibility across different systems
250- add flags -ffp-contract=off and /fp:precise to enhance reproducibility across different systems
257- added parameter "propagating/symmetry/symtiming" to determine when symmetries are computed and handled
259### Changed parameters
261- Disabled "propagating/symmetry/addconsstiming" since it is not used anymore.
262- Disabled "propagating/symmetry/ofsymcomptiming" since it is not used anymore.
264@section RN900 SCIP 9.0.0
265*************************
270- added simplification of abs(x)^n to x^n when n is even (simplify rule POW12)
271- in expression simplification, added possibility to expand power of sum with exponents larger than 2 (simplify rule POW7)
272- in expression simplification, added possibility to expand products with sums as factor when there are more than two factors (simplify rule SP12b)
273- in expression simplification, added possibility to allow expanding power of products with fractional exponent (simplify rule POW5a)
274- can now build with Lapack (used for solving nonlinear problems) explicitly; if IPOPT is used, then Lapack is accessed through it;
275 an interface to Lapack is available in lapack_calls.h
276- added support for logical constraints in binary variables and basic logical operators (and, or, not, equal) to AMPL .nl reader
277- indicator constraints now use the same slack variable for the linear constraints if binary variables are used multiple times
278 for indicator constraints
279- new diving heuristic indicatordiving that focuses on indicator variables which control semicontinuous variables
280- updated statistics on NLP relaxation; information on convexity of NLP has been added
281- added new bandit method (EXP.3-IX) that is the new default of the ALNS heuristic
282- added dialog to display recognized permutation symmetries ("display symmetry")
283- The symmetry detection code has been completely restructured. Instead of completely encoding symmetry information in
284 prop_symmetry.c, there is a new callback for constraint handlers, which returns symmetry relevant information by
285 encoding a constraint as a node and edge colored graph. This way, also custom constraint handlers can provide
286 symmetry information.
287- added special presolving step for logicor and set covering/packing for constraints with two variables and one independent variable
288- increased the depth field of the tree structure from 16 to 30 bits and the max depth of the search tree from 65534 to 1073741822
289- added new cut selector plugin called cutsel_ensemble. Performs a superset of hybrid cutsel. Implements new filtering methods and scoring options.
290- added new branching rule based on Gomory mixed-integer cuts
291- added new branching score to the reliability pseudo-cost branching rule
292- added new cut selector plugin called cutsel_dynamic. Performs a superset of hybrid cutsel. Implements new filtering methods and scoring options.
293- added monoidal strengthening to intersection cut generation of nlhdlr_quadratic
294- extended heuristic dps to run after processing the node and to use strict limits for the reoptimization step
295- extended obbt propagator to handle variables of the linear constraints corresponding to indicator constraints
296- added new heuristic heur_scheduler that models the selection of LNS and diving heuristics as a multi-armed bandit problem
297- added nonlinear handler for signomial expressions: adds cuts based on a difference of convex functions representation
298- Delayed separators are now called if no other cuts have been found. Previously, such separators were only called near stalling or when the separation rounds limit was reached.
299- added a new separator sepa_lagromory to generate Lagromory cuts in a relax-and-cut framework, i.e., GMI cuts generated
300 at different bases that are explored in the process of solving the Lagrangian dual problem at a node. This separator
302- when parsing nonlinear constraints from CIP files, the * after the number in a term is now optional if followed by a variable,
303 i.e., instead of 3*<x>*<y>, now also 3<x>*<y> can be read, but 3<x><y> is not supported;
304 this allows to read some CIP files that were written with SCIP < 8
305- when running bliss, we now limit the number of actually created generators and not the ones considered by bliss
307Performance improvements
308------------------------
310- Variable conflict-based addition of Schreier-Sims cuts for symmetry handling in prop_symmetry.c does no longer use
311 an expensive explicit conflict graph construction.
312- Only run propagation of indicator constraints if relevant variables have changed.
313- Propagation of indicator constraints propagates maximal activity of linear constraint to upper bound of slack variable.
314- Added initialization of LP relaxation for SOC constraints.
315- Avoided some numerical issues when separating SOC constraints.
316- If differentation of convex expression fails in convex nlhdlr, then a perturbed point is tried.
317- Use sassy/bliss as default symmetry computation package.
318- No longer linearize indicator constraints in undercover heuristic by default.
319- Deactivate pre-root heuristic zeroobj in undercover heuristic.
320- Added new branching score tiebreaker for reliability pseudo-cost branching rule
321- Try nearest bound if zero solution value is out of bounds in heuristic trivial.
326### New and changed callbacks
328- Added solution linearization callback for nonlinear handlers.
329 The nonlinear handler may use this callback to add tight cuts that use the given solution as reference point to the cutpool.
330 The callback is called if option constraints/nonlinear/linearizeheursol is enabled.
331- The callback for copying problem data SCIP_DECL_PROBCOPY() now has a parameter "original" indicating whether the original
332 or transformed problem should be copied. Similarly, SCIPprobCopy() in prob.h/c has such a parameter.
333- Added CONSGETPERMSYMGRAPH and CONSGETSIGNEDPERMSYMGRAPH callback for constraint handlers, which provides symmetry information about constraints to SCIP.
335### Deleted and changed API methods
337- SCIPtpiInitLock(), SCIPtpiDestroyLock(), SCIPtpiInitCondition(), SCIPtpiDestroyCondition() now take a double
338 pointer to SCIP_LOCK/SCIP_CONDITION, respectively.
339- Renamed SCIPtpiSumbitJob() to SCIPtpiSubmitJob().
340- SCIPcreateConsIndicatorLinCons(), SCIPcreateConsIndicatorGenericLinCons() do not allow binvar to be NULL anymore
341- Replaced SCIPnlrowSetCurvature() by SCIPsetNlRowCurvature().
342- SCIPsnprintf() now returns the required string length in case reallocation is necessary.
343- SCIPcomputeCoverUndercover() receives three more arguments which nonlinearities to cover
344- removed definition of SQRT
345- SCIPincludeObjConshdlr(), SCIPincludeConshdlr(), SCIPconshdlrCreate() receive two more arguments for the
346 conshdlr callbacks CONSGETPERMSYMGRAPH and CONSGETSIGNEDPERMSYMGRAPH
347- removed SYM_VARTYPE, SYM_OPTYPE, SYM_CONSTTYPE, SYM_RHSTYPE, SYM_MATRIXDATA
348- new parameter issigned for SCIPcomputeOrbitsSym()
349- new parameter symtype for SCIPcomputeComponentsSym()
350- new parameter symtype and permvardomaincenter for SCIPlexicographicReductionAddPermutation()
351- replaced parameters matrixdata and exprdata of SYMcomputeSymmetryGenerators() by graph
355- new functions for interfacing with Lapack: SCIPlapackIsAvailable(), SCIPlapackIsAvailable(), SCIPlapackComputeEigenvalues(), and SCIPlapackSolveLinearEquations
356 These functions should be used instead of SCIPisIpoptAvailableIpopt(), SCIPcallLapackDsyevIpopt(), and
357 SCIPsolveLinearEquationsIpopt() in the context of computing eigenvalues or solving linear equations.
358 If IPOPT is available, the calls will be passed on to Ipopt's interface to Lapack.
359- SCIPmultiplyBySumExprSum(), SCIPpowerExprSum()
361- SCIPgetPrimalDualIntegral() returns the primal dual integral stored in the statistics
362- new functions SCIPcreateConsIndicatorLinConsPure() and SCIPcreateConsIndicatorGenericLinConsPure() that
363 create indicator constraints from a linear constraint without a slack variable
364- SCIPgetNLPNlRowsStat() to retrieve counts on linear, convex, and nonconvex rows in NLP
365- SCIPnlhdlrSetSollinearize(), SCIPnlhdlrHasSollinearize()
366- SCIPbendersGetNLPParam()
367- new API functions SCIPlexicographicReductionGetStatistics(), SCIPlexicographicReductionPrintStatistics(),
368 SCIPlexicographicReductionPropagate(), SCIPlexicographicReductionAddPermutation(), SCIPlexicographicReductionReset(),
369 SCIPlexicographicReductionFree(), SCIPincludeLexicographicReduction(), for lexicographic reduction.
370- new API functions SCIPorbitopalReductionGetStatistics(), SCIPorbitopalReductionPrintStatistics(),
371 SCIPorbitopalReductionPropagate(), SCIPorbitopalReductionAddOrbitope(), SCIPorbitopalReductionReset(),
372 SCIPorbitopalReductionFree(), SCIPincludeOrbitopalReduction(), SCIPorbitopalReductionGetDefaultColumnOrdering(),
373 for orbitopal fixing.
374- new API functions SCIPorbitalReductionGetStatistics(), SCIPorbitalReductionPrintStatistics(),
375 SCIPorbitalReductionPropagate(), SCIPorbitalReductionAddComponent(), SCIPorbitalReductionReset(),
376 SCIPorbitalReductionFree(), SCIPincludeOrbitalReduction(), for orbital fixing.
377- new API functions SCIPgetShadowTreeEventHandlerExecutionTime(), SCIPshadowTreeGetShadowNodeFromNodeNumber(),
378 SCIPshadowTreeGetShadowNode(), SCIPgetShadowTree(), SCIPactivateShadowTree(), SCIPincludeEventHdlrShadowTree(),
379 for managing a copy of the branch-and-bound tree for symmetry handling purposes.
380- SCIPdotWriteOpening(), SCIPdotWriteNode(), SCIPdotWriteArc(), SCIPdotWriteClosing()
381- SCIPincludeCutselEnsemble(), SCIPselectCutsEnsemble() to include cutsel_ensemble or use the selection algorithm
382- SCIPincludeBranchruleGomory() includes new gomory cut based branching rule
383- SCIPgetVarAvgGMIScore(), SCIPincVarGMISumScore(), SCIPgetVarLastGMIScore(), SCIPsetVarLastGMIScore() set historical values used by SCIP's default branching rule
384- SCIPincludeNlhdlrSignomial() includes the signomial nonlinear handler
385- SCIPgetExprMonomialData() returns a monomial representation of a product expression
386- SCIPestimateRoot() computes estimators for roots with exponent in [0,1]
387- SCIPincludeCutselDynamic(), SCIPselectCutsDynamic() to include cutsel_dynamic or use the selection algorithm
388- SCIPincludeSepaLagromory() to include the new Lagromory separator
389- SCIPconsCompCheck() to compare two constraints based on their check priority
390- SCIPgetConsPermsymGraph() and SCIPgetConsSignedPermsymGraph() to access the (signed) permutation symmetry detection graph of a constraint
391- SCIPsetConshdlrGetPermsymGraph() and SCIPsetConshdlrGetSignedPermsymGraph() to set the (signed) permutation symmetry detection graph of a constraint
392- SCIPconshdlrSupportsPermsymDetection() and SCIPconshdlrSupportsSignedPermsymDetection() to access whether a conshdlr supports detection of (signed) permutation symmetries
393- new API functions for creating and manipulating a symmetry detection graph: SCIPcreateSymgraph(), SCIPfreeSymgraph(), SCIPcopySymgraph(), SCIPextendPermsymDetectionGraphLinear(),
394 SCIPaddSymgraphVarAggregation(), SCIPaddSymgraphOpnode(), SCIPaddSymgraphValnode(), SCIPaddSymgraphConsnode(), SCIPgetSymgraphVarnodeidx(), SCIPgetSymgraphNegatedVarnodeidx(),
395 SCIPupdateSymgraphLhs(), SCIPupdateSymgraphRhs(), SCIPfixSymgraphVarnode(), SCIPaddSymgraphEdge(), SCIPcomputeSymgraphColors(), SCIPgetSymgraphSymtype(), SCIPgetSymgraphVars(),
396 SCIPgetSymgraphNVars(), SCIPgetSymgraphNConsnodes(), SCIPgetSymgraphNNodes(), SCIPgetSymgraphNEdges(), SCIPgetSymgraphEdgeFirst(), SCIPgetSymgraphEdgeSecond(),
397 SCIPgetSymgraphVarnodeColor(), SCIPgetSymgraphNodeType(), SCIPgetSymgraphNodeColor(), SCIPisSymgraphEdgeColored(), SCIPgetSymgraphEdgeColor(), SCIPgetSymgraphNVarcolors(),
398 SCIPhasGraphUniqueEdgetype(), SCIPallocateSymgraphConsnodeperm(), SCIPcreateSymgraphConsnodeperm(), SCIPgetSymgraphConsnodeperm(), SCIPfreeSymgraphConsnodeperm(),
399 SCIPgetSymActiveVariables(), SCIPfreeSymDataExpr(), SCIPgetSymExprdataNConstants(), SCIPgetSymExprdataConstants(), SCIPgetCoefSymData(),
400 SCIPcreateSymOpNodeType(), SCIPgetSymOpNodeType()
401- SCIPexprhdlrSetGetSymdata(), SCIPexprhdlrHasGetSymData(), SCIPgetSymDataExpr(), SCIPcallExprGetSymData() to access symmetry data of expressions
402- SYMcheckGraphsAreIdentical() to check whether two symmetry detection graphs are identical
403- new functions SYMbuildSassyGraph(), SYMbuildSassyGraphCheck()
405- new definitions SCIP_DECL_CONSGETPERMSYMGRAPH, SCIP_DECL_EXPRGETSYMDATA
406- new member SYM_NODETYPE_CONS in SYM_NODETYPE enum
407- new members SYM_CONSOPTYPE_SUM, SYM_CONSOPTYPE_SLACK, SYM_CONSOPTYPE_COEF, SYM_CONSOPTYPE_RHS, SYM_CONSOPTYPE_LAST in SYM_CONSOPTYPE enum
408- new defintion SCIP_DECL_EXPRGETSYMDATA
409- new function SCIPdetectSingleOrDoubleLexMatrices()
411### Command line interface
413- Added optional parameter -i when calling SCIP in AMPL-mode (-AMPL parameter).
414 If -i is specified, a SCIP shell is started where normally SCIPsolve() would be called.
416### Interfaces to external software
418- added interface to nauty/traces for symmetry computation
419- added interface to sassy, a preprocessor for symmetry computation
420- The directory src/sassy contains the source code of sassy.
421- Added interface to Lapack (used for solving nonlinear problems).
422- The AMPL interface now supports parameters specified in AMPL command scripts via option scip_options.
423 The value of scip_options is expected to be a sequence of parameter names and values, separated by a space, e.g.,
424 `option scip_options 'limits/time 10 display/verblevel 1';`.
425 String values should not be quoted and spaces in string values are not supported.
426- sassy can be used now as preprocessor for nauty/traces
427- The solution status codes written to AMPL solution files now match those from https://mp.ampl.com/details.html#_CPPv4N2mp3sol6StatusE.
429### Changed parameters
431- change default value of parameter separating/filtercutpoolrel to FALSE
432- Shrunk range of parameter "propagating/symmetry/sstleaderrule" from [0,3] to [0,2], removed "MAXCONFLICTS"-option.
433- Removed reading/gmsreader/freeints. A default upper bound of +inf is now assumed for integer variables in GAMS (which is the case since GAMS 23.1).
434- Disabled "propagating/symmetry/symfixnonbinaryvars" since it is not used in the new symmetry code.
435- Replaced "propagating/symmetry/onlybinarysymmetry" with "propagating/symmetry/enforcecomputesymmetry" and set to FALSE by default.
436- Disabled "propagating/symmetry/performpresolving" since running orbital reduction during presolving is not effective.
437- Repurposed "propagating/symmetry/usedynamicprop" since it now also applies to lexicographic reduction.
438- Changed default value of parameter "propagating/symmetry/addsymresacks" from FALSE to TRUE.
442- separating/maxcutsgenfactor and separating/maxcutsrootgenfactor as factors (w.r.t. separating/maxcuts and
443 separating/maxcutsroot) for limits on the number of cuts generated (which used to be constants '2')
444- expr/pow/expandmaxexponent to specify limit on exponent when to expand power of sum
445- expr/pow/distribfracexponent to enable expanding power of products with fractional exponents
446- expr/product/expandalways to enable expanding any product with sums as factor (that is, also when more than two factors)
447- nlhdlr/convex/maxperturb to specify maximal perturbation of non-differential reference points
448- benders/default/nlpiterlimit to adjust iteration limit for NLP solver for Benders' decomposition NLP subproblems
449- limits/objectivestop to interrupt the solve as soon as a primal solution is found
450 that is at least as good as the given value
451- heuristics/undercover/{coverand,coverind,covernl} to control which nonlinearities to consider (by default only "and" and nonlinear constraints)
452- cutselection/ensemble/∗ all parameters for new ensemble cut selector
453- cutselection/dynamic/∗ all parameters for new dynamic cut selector
454- branching/relpscost/gmiavgeffweight specifies the weight in the relpscost branching score of the normalized efficacy of all generated GMI cuts (for a variable)
455 branching/relpscost/gmilasteffweight specifies the weight in the elpscost branching score of the normalized efficacy of the last generated GMI cut (for a variable)
456- nlhdlr/quadratic/usemonoidal to enable monoidal strengthening when separating quadratics with intersection cuts
457- nlhdlr/quadratic/trackmore to collect more statistics for monoidal strengthening when separating quadratics with intersection cuts
458- nlhdlr/quadratic/useminrep to use the minimal representation to compute cut coefficients when separating quadratics with intersection cuts
459- nlhdlr/quadratic/sparsifycuts to enable sparsification of intersection cuts for quadratics
460- heuristics/dps/reoptlimits to set strict limits for the reoptimization step in dps
461- heuristics/dps/timing to run dps after processing the node
462- heuristics/scheduler/∗ all parameters for new scheduler heuristic
463- nlhdlr/signomial/enabled, nlhdlr/signomial/maxnundervars, nlhdlr/signomial/mincutscale: parameters for the signomial nonlinear handler
464- separating/lagromory/freq to denote the frequency for calling Lagromory separator
465- separating/lagromory/away to denote the minimal integrality violation of a basis variable to try separation
466- separating/lagromory/dynamiccuts to denote whether the generated cuts be removed from LP if they are no longer tight
467- separating/lagromory/maxroundsroot to denote the maximal number of separation rounds in the root node
468- separating/lagromory/maxrounds to denote the maximal number of separation rounds in a non-root node
469- separating/lagromory/nmaxcutsperlproot to denote, in the root node, the maximal number of Lagromory cuts that can be
470 separated per explored basis of the Lagrangian dual
471- separating/lagromory/nmaxcutsperlp to denote, in a non-root node, the maximal number of Lagromory cuts that can be
472 separated per explored basis of the Lagrangian dual
473- separating/lagromory/perroundnmaxlpiters to denote the maximal number of separating LP iterations that are allowed per
475- separating/lagromory/dualdegeneracyratethreshold to denote the minimum dual degeneracy rate for the separator execution
476- separating/lagromory/varconsratiothreshold to denote the minimum variable-constraint ratio on the optimal face for the
478- many other advanced parameters for the Lagromory separator, which are also mentioned under separating/lagromory/∗
482- new data structure SYM_GRAPH to encode symmetry information from a constraint
483- new data structure SYM_EXPRDATA to encode symmetry information from expressions
484- replaced enum SYM_SYMTYPE by a complete new one; removed SYM_RHSSENSE, added SYM_NODETYPE and SYM_CONSOPTYPE
489- deleted the now unused files: tpi_none.h, tpi_openmp.h, tpi_tnycthrd.h, type_tpi_none.h, type_tpi_openmp.h, type_tpi_tnycthrd.h
494- new unittests for nlhdlr_quadratic that test monoidal strengthening and the use of the minimal representation to compute cut coefficients
495- unittests for nlhdlr_signomial
500- changed `set lim obj` to `set lim objective` in ctest since `obj` is no longer unambiguous
507- New flag -DLAPACK=on for linking with Lapack (must be available in the system)
508- added flag option "SYM=sbliss" for using sassy/bliss as a graph automorphism package
509- use SYM=sbliss by default, since sassy and bliss are now shipped with SCIP.
510- added flag option "SYM=snauty" for using sassy/nauty as a graph automorphism package
514- added flag option "nauty" for SYM variable to specify which graph automorphism package should be used
515- added flag option "sbliss" (sassy/bliss) for SYM variable to specify which graph automorphism package should be used
516- added flag option "snauty" (sassy/nauty) for SYM variable to specify which graph automorphism package should be used
517- use SYM=sbliss by default, since sassy and bliss are now shipped with SCIP
518- New flag LAPACK for linking with Lapack (must be available in the system)
519- A file scip/config.h is created in the build directory ($(OBJDIR)/include) now.
520 Defining NO_CONFIG_HEADER is no longer necessary and has no effect anymore.
525- Number of runs in which separation is enabled will now be correct as per "separating/maxruns" parameter. Earlier,
526 separation was enabled for "maxruns + 1" number of runs, i.e., separation was enabled even when "maxruns = 0" was set.
527- add safeguard for number of selected cuts
528- use double double precision for delta in activity updates of cons_linear.c
529- sort constraints in checkSolOrig() to keep the logic of constraint handlers intact
530- fixed make install when SHARED=no and make uninstall
531- check absolute coefficients relative to extremal average to avoid invalid unifications in normalizeCons()
532- enforce and check symmetry-based constraints to take their locks (in dual reductions) into account
533- flush changes at the end of SCIPlpiSetBase() in lpi_grb.c to apply the newly set basis correctly
538- The TPI has been changed to become mostly independent from the actual parallel interface during compile time.
539 For this, the locks and conditions are now pointers to abstract structs.
540- fixed that scip/def.h, the header for C preprocessor definition (`#define`'s), included headers for some SCIP type and function definitions
541 (scip/type_retcode.h, scip/type_message.h, scip/pub_message.h)
544@page RN8 Release notes for SCIP 8
546@section RN810 SCIP 8.1.0
547*************************
552- fixed that scaling of rows in Gurobi interface (SCIPlpiScaleRow()) changed infinite sides to large finite ones (1e20) when scale factor is negative
553- check whether objective limit is truly reached in SCIPlpiIsStable()
554- if an objective limit is set and Mosek claims that it is exceeded, check that this is indeed the case in SCIPlpiIsStable()
555- the .mps file reader was extended to additionally accept .mps files with the objective sense section on one line
556- ensure that delayed cutpool separation does not happen if enough cuts have been found already
557- fixed that a Gurobi or Mosek interface (LPI) could not be freed from a thread different than the one it was created in, which lead to problems when, e.g., using the concurrent optimizer
558- in cons_varbound if both variables are fixed, instead of propagating the constraint check the feasibility of the constraint since propagating can lead to unnecessary numerical troubles
559- fixed memory leak in branching rule "distribution"
560- fixed that undercover did not enforce that sufficiently many variables in an and-constraints were fixed to have it linearized in the generated sub-scip
561- fixed two bugs in cons_varbound: avoid adding variable bounds if vbdcoef is infinite and unlock/lock variables if lhs/rhs/vbdcoef are changed
562- globalize constraint changes before bound changes during the effective root shift in treeSwitchPath() to correctly update variable locks by avoiding global bounds with outstanding bound change events when deleting constraints
563- fixed error when attempting to copy SCIP with activated pricers
564- remove integrality check for implicit integral variables in cons_integral.c, updated the definition for variable type implicit integer to be more explicit that these variables can take fractional values, and updated FAQ entry
565- updated and, or, and pseudoboolean constraint handlers to better handle fractional implicit integer variables in enforcement
566- avoid invalid strong Chvatal-Gomory cuts by ceiling with tolerance in the calculation of parameter k and flooring slack coefficients with standard epsilon tolerance as well as quad precision
567- add missing row links to columns in SCIPflushRowExtensions() required to maintain correct row norms
568- restrict separator intobj to solutions for which there can be no better feasible integral objective values to avoid cutting them off
569- delay removal of clique lists from SCIPvarRemoveCliquesImplicsVbs() into cliqueCleanup() to avoid segmentation faults by incomplete cleanups after variable conversions
570- reject sub-solutions with invalid objectives in SCIPtranslateSubSols() due to contradicting infinite contributions
571- correct column index in getMinMaxActivityResiduals() to make presolver dualinfer work
572- copy quiet flag from main scip's message handler to the one of solverscip in concurrent optimization
573- avoid bound tightening cycles towards huge redundancy bounds in fullDualPresolve() to avert fatal numerical trouble in representing vertices of linear relaxations with unbounded domains
574- fix problem where debug solution did not work if branching constraints are present
575- update index of dominating variable on coefficient deletion in dualPresolving() of constraint handler logicor
576- pass on flags from a redundant to the implying varbound constraint in preprocessConstraintPairs() to avoid suboptimal fixings by model relaxations
577- apply reductions of dualinfer only if a dual solution exists (primal is bounded)
578- before presolving is finished check solutions before retransforming them including tiny values to keep check flags consistent
579- disable heuristics before and during presolving in benders decomposition to avoid messing up the objective structure in the solution store by dropping auxiliary variables in the required retransformations
580- correct local flag of singleton conflict constraints in tightenSingleVar() against invalid bound globalization
581- respect unboundedness in the computation of activity bounds in conflict.c to avoid invalid huge bounds due to small coefficients on unbounded variables
582- ensure positive sides of a linear constraint when recognizing a set partition in rangedRowSimplify() to account for redundancy issues
583- relax numerical conditions for variable aggregations to avert invalid variable fixings
584- fixed harmless read of uninitialized data when creating parameters
585- fix call of SCIPnlpiOraclePrintProblem in nlpi_worhp
587Performance improvements
588------------------------
590- Use sassy/bliss as default symmetry computation package.
595### Interfaces to external software
597- added interface to nauty/traces for symmetry computation
598- added interface to sassy, a preprocessor for symmetry computation
599- The directory src/sassy contains the source code of sassy.
606- added flag option "SYM=sbliss" for using sassy/bliss as a graph automorphism package
610- added flag option "nauty" for SYM variable to specify which graph automorphism package should be used
611- added flag option "sbliss" for SYM variable to specify which graph automorphism package should be used
612- use SYM=sbliss by default, since sassy and bliss are now shipped with SCIP
617- the parameter change callback is no longer called at the moment a parameter is created
619@section RN804 SCIP 8.0.4
620*************************
625- use quad precision in cutsSubstituteMIR() for substituting slack variables into CMIR cuts
626- use quad precision for activity computations in cons_linear.c
628### Deleted and changed API methods
630- SCIPshrinkDisjunctiveVarSet() no longer attempts to cutoff the current node if it finds the
631 given disjunction to be infeasible; it is now in the responsibility of the caller to act accordingly
636- added XML parser routines from src/xml/xml.h
638### Interfaces to external software
640- updated XPRESS interface to work with XPRESS 41 as well
641- new interface to LP solver HiGHS (lpi_highs.cpp)
643### Changed parameters
645- changed integer parameter "propagating/symmetry/recomputrestart" from range {0, 1, 2} to being fixed at value 0
650- added new checks for objective, bounds and sides inside the scaling tests in lpi/change.c
655- relax condition of assert in lpSolve to hold only if lp/checkstability is true
656- OPB reader: dynamically increase the size of the line buffer for reading in getMaxAndConsDim()
657- Enabled the solution limit checks in SCIPsolveIsStopped in solve.c when in SCIP_STAGE_PRESOLVING
658- fix quad precision comparison for the calculation of knapsackcover constraints.
659- force copying of symmetry constraints for concurrent solve
660- increase the precision of double multiplications in quad precision environments
661- corrected handling of different variable types in symmetry
662- orbitope detection: refine computation of overlap structure and fixed bug in finding orbitope generators
663- ensure that winner is always determined in concurrent mode
664- when a row with invalid index range is added to the global cutpool, update the indices instead of failing with an assert
665- update of watched literals in cons_xor.c and ensure that fixed variables are counted in propacateCons()
666- avoid some numerical issue in check for redundant variables in linear constraints (introduced with version 8.0.2)
667- more rows are treated as being integral in cutsSubstituteMIR() for CMIR cuts
668- fixed several relaxations of the rhs of cuts to 0 in cuts.c
669- avoid aggregation into a single linear constraint if they should not be upgraded (needed for indicator constraints)
670- apply effective root changes before fork is repropagated during treeSwitchPath() in tree.c
671- avoid invalid objective value for solutions generated from an unbounded LP relaxation in case of a nonlinear objective function
672- disable recomputing symmetries after a restart (constraint removal is not permitted)
673- avoid cutting off optimal solutions for small feasibility tolerances in conflict analysis
674- initialize variable in presol_dualsparsify.c
675- fix in presolving of variable bound constraints to use absolute instead of relative difference
676- free variable histories in reoptimization mode
677- handle whitespaces in interactive shell history consistently
678- check and enforce equalities on which the objective is projected in cons_linear.c
679- ensure row feasibilities of solution shiftings in heur_oneopt.c and heur_twoopt.c
680- remove rounded row check blocking tolerable primal solutions in cons_varbound.c
681- fixed that presolve of logicor-constraints may have attempted to cutoff a root of the not yet existing branch-and-bound tree
682- only consider positive slack variables as active in benders.c
683- in the feasibility check of and/or constraints, allow for fractional values in operands
684- fixed linear outer-approximation for some composite absolute-value expressions
689- Extended documentation of the parameter limits/solutions to point out that the limit is first checked in presolving
690- Added more information about using SCIPcache- and SCIPflushRowExtensions() to documentation and comments
691- Extended the `how to add' sections of the documentation by adding information on how to include default plugins into SCIP
693@section RN803 SCIP 8.0.3
694*************************
696Examples and applications
697-------------------------
699- Externalize STP and PolySCIP applications
704### Command line interface
706- When running the AMPL interface, the .nl filename extension does not need to be omitted for the input file anymore.
713- Forbid CMAKE_BUILD_TYPE nonstandard values
714- Move -I/path/to/src/amplmp/include to front of compiler flags for include directories
721- fixed an incorrect handling of xor constraints
722- the feasibility checker for integrality constraints now uses checkintegrality even for implied integers
723- skip integrality check in cons_integral for relaxation-only implicit-integer variables
724- fixed an issue caused by aggregated variables not added to a hashmap in the xor constraint handler
725- changed function solveRowEchelonGF2 in cons_xor.c to avoid errors if rank is 0
726- fixed that the implication presolver tried to aggregate or tighten bounds of multiaggregated variables
727- fixed a sign check in detection of linear constraints that are parallel to the objective
728- fixed bug in Clp and lpi_clp with missing basis information when calling the barrier with crossover; needs new Clp version
729- do not assume aggregation is successful in cons_setppc.c
734- Changed license to Apache 2.0, see https://www.apache.org/licenses/LICENSE-2.0.
735- When an LP could not be solved accurately, scaling is now turned off as a last fall-back method.
736- Methods for using the debug solution mechanism SCIPdebugAddSolVal, SCIPdebugGetSol, SCIPdebugGetSolVal,
737 SCIPdebugSolIsValidInSubtree, SCIPdebugIsMainscip, SCIPdebugSolEnable, SCIPdebugSolDisable, SCIPdebugSolIsEnabled,
738 SCIPwithDebugSol are now exported
740@section RN802 SCIP 8.0.2
741*************************
746### Deleted and changed API methods
748- added input parameter SCIP_Bool initiallp to SCIPcutselsSelect
749- changed function type int to SCIP_Longint for SCIPcutpoolGetMaxNCuts
750- replaced SCIPsepastoreGetNCutsFound with SCIPsepastoreGetNCutsAdded following the naming convention for the new statistics
751- replaced SCIPsepaIncNAppliedCuts with SCIPsepaIncNCutsApplied
755- added SCIPsepastoreGetNCutsAdded, SCIPsepastoreGetNCutsAddedViaPool, SCIPsepastoreGetNCutsAddedDirect
756- added SCIPsepaIncNCutsAdded, SCIPsepaDecNCutsAdded, SCIPsepaIncNCutsApplied, SCIPsepaGetNRootCalls, SCIPsepaGetNCutsAdded, SCIPsepaGetNCutsAddedViaPool, SCIPsepaGetNCutsAddedDirect, SCIPsepaGetNCutsAppliedViaPool, SCIPsepaGetNCutsAppliedDirect
757- added SCIPcutpoolGetNRootCalls, SCIPcutpoolGetNCutsAdded, SCIPcutpoolAddMaxNCuts, SCIPcutpoolSetTime, SCIPcutpoolAddNCalls, SCIPcutpoolAddNRootCalls, SCIPcutpoolAddNCutsFound, SCIPcutpoolAddNCutsAdded,
758- added SCIPcutselGetNCalls, SCIPcutselGetNRootCalls, SCIPcutselGetNRootCuts, SCIPcutselGetNRootForcedCuts, SCIPcutselGetNRootCutsFiltered, SCIPcutselGetNLocalCuts, SCIPcutselGetNLocalForcedCuts, SCIPcutselGetNLocalCutsFiltered,
760### Interfaces to external software
762- Added compatibility with Mosek 10.0.18.
766- new parameters to turn on more statistics: misc/showdivingstats (diving heuristics), heuristics/alns/shownbstats (ALNS), estimation/showstats (tree size estimation)
770- added nrootcalls and ncutsadded to SCIP_Cutpool
771- added fromcutpool flag to SCIP_Row and fixed 33 bit allocation
772- added ncalls, nrootcalls, nrootcutsselected, nrootcutsforced, nrootcutsfiltered, nlocalcutsselected, nlocalcutsforced, nlocalcutsfiltered to SCIP_Cutsel
773- added ncutsadded, ncutsaddedviapool, ncutsaddeddirect, ncutsappliedviapool, ncutsapplieddirect, nrootcalls to SCIP_Sepa
774- added ncutsadded, ncutsaddedviapool, ncutsaddeddirect to SCIP_Sepastore
775- fixed statistics of relaxators w.r.t. number of times conss/cuts were added
782- new option `-DAUTOBUILD` that configures scip with dependencies on availability.
783 Packages like Ipopt, PaPILO, Readline, Zimpl, ZLIB, GMP, Worhp are automatically found and linked, otherwise ignored.
784 The individual flags for these packages are ignored. This makes a quick build easier. It is by default set to off.
789- read objective offset from ZIMPL files
790- Make sure that objective limit is disabled if not all variables are in the LP. If we would run into
791 an objective limit in this case, the results of the LP solver are unclear.
792- fixed bug in reopt.c, which occured for bounds outside of current valid bounds
793- fixed problem with recomputing symmetries after a restart
794- fixed bug in SCIPcalcMIR() with wrong order of arguments for removeZerosQuad()
795- fixed segmentation fault in update of cut statistic
796- fixed bug in presolving of and constraints by merging variables with multiple occurrences before cliquePresolve()
797- fixed bug in dual presolving of linear constraints by setting implicit integers to integers in multi-aggregation
798- fixed update of presolve statistics on added constraints and changed coefficients in constraint handler for nonlinear constraints
799- fixed bug with reading CIP files with large constraints split over several lines
800- fixed bug with infinite bounds in the computation of conflict cuts
801- fixed check for unbounded solution constructed by SCIPlpGetUnboundedSol(): The constructed solution is very likely infeasible
802 since scaling increases small numerical feasibility violations. Therefore, the solution is now always accepted. However, the
803 feasibility of the ray is now checked. This fix now might lead to several rounds of separation in order to resolve unbounded solutions,
804 whereas previously SCIP started to branch immediately.
805- changed to absolute tolerances in all redundancy checks for linear constraints
810- Added extended cutselector statistics splitting between root node specific and general statistics
811- Added extended and refined cutpool statistics showing the number of cuts added from the cutpool to the sepastore
812- Added extended and refined separator statistics to get a better view of the individual generators performance
813- turned off output of statistics for the following information by default:
814 diving heuristics, ALNS neighborhood information and tree size estimation statistics;
815 they can be turned on using the following new parameters:
816 misc/showdivingstats (diving heuristics), heuristics/alns/shownbstats (ALNS), estimation/showstats (tree size estimation)
818@section RN801 SCIP 8.0.1
819*************************
824- clique lifting in cons_setppc (parameter enablecliquelifting) is only disabled if it has been applied
825- avoid warning if Mosek has reached/exceeded the objective limit
826- improved curvature check for quadratic expressions when extended formulations are disabled
828Examples and applications
829-------------------------
831- Fixed handling of enforcing in the TSP example.
836### Interfaces to external software
838- Added compatibility with Mosek 10.0.13.
843- BLISS is now built from the vendored version from https://github.com/ds4dm/Bliss
847- avoid warnings about unrecognized compiler warning silencing options when compilation with GCC fails
848- adjust mosek find module to version 9.3
849- added cmake compatibility for ipopt versions 3.14.x
853- avoid warnings about unrecognized compiler warning silencing options when compilation with GCC fails
854- fixed that compilation with MS/Intel compilers on Windows and Cray compilers was broken when enabling PAPILO
859- fixed uninitialized array in detection of suborbitopes
860- Fixed problem with reading long lines in LP/FZN/OPB/Diff-files. The buffer is now reallocated,
861 which also should be much faster.
862- fixed that recursive products in expressions were sometimes not flattened
863- fixed that expressions in original variables could not be simplified
864- fixed handling of objective limit with Mosek
865- made SCIPlpiGetSolverName()/SCIPlpiGetSolverDesc() thread-safe for LP Solvers (Cplex,Gurobi,Glop,Mosek,SoPlex,Xpress)
866- made SYMsymmetryGetName() thread-safe for Bliss
867- fixed memory allocation issue in detection of SOC nlhdlr
868- fixed that reaching the walltime limit in Ipopt was not handled properly
869- Deactivated dual fixing of unlocked variables with zero objective in presol_milp that SCIP is unable to postsolve.
870- set the column flag kImplInt for implicit integers in the papilo problem
871- fixed bug in propagation of indicator constraints (one case always reported a change through propagation)
873@section RN800 SCIP 8.0.0
874*************************
879- Variables that were marked as relaxation-only and that were not used in any solution (SCIP_SOL)
880 are now deleted when during a restart.
881- New symmetry handling method, symmetry handling inequalities based on the Schreier Sims table,
882 which is able to handle symmetries of arbitrary kinds of variables.
883- Revise way in which external memory (e.g., of LP-solver) is estimated.
884- The symmetry code can now heuristically search for orbitopes that do not completely handle
885 a symmetry component and add certain Schreier Sims cuts to such components.
886- The LPIs for Gurobi and Mosek are thread-safe now.
887- The complete code is now thread-safe by default.
888- New separator to generate mixing cuts (works well for stochastic programming with probabilistic constraint).
889- New parsing routines for cons_orbisack and cons_symresack.
890- Variables can now be marked to forbid aggregation.
891- Heuristic PADM can now reoptimize found solution with original objective function.
892- Added code to support debugging of catching or releasing of variables to var.c (prints backtrace
893 when catching and releasing).
894- SCIPintervalSin() and SCIPintervalCos() are now rounding-safe.
895- Removed special handling of second-order cones in undercover heuristic for now.
896- Removed use of Hessian sparsity pattern for nonquadratic nonlinear constraints in undercover heuristic.
897- Added reader for AMPL .nl files.
898- New separator sepa_rlt to compute cuts via the reformulation-linearization technique (RLT).
899- New separator sepa_minor to compute cuts from 2x2 minors of a violated semidefiniteness constraint that is
900 implied by the extended formulation for bilinear products.
901- New separator sepa_interminor to compute intersection cuts from 2x2 (not only principle) minors of a violated
902 rank-one constraint that is implied by the extended formulation for bilinear products.
903- Symmetry handling has been extended to detect also symmetries between variables that also appear in nonlinear constraints.
904- Improved OBBT propagator by only considering variables that are contained in at least one nonconvex expression that has an auxiliary variable.
905- Default parameter settings for NLP solves are now defined independently of the NLP solver.
906- Added table to print statistics on NLP solvers.
907- Knapsack, linear, logicor, setppc, and varbound constraints now add themselves to the NLP relaxation, if enabled.
908 And, linking constraints and bounddisjunctions in one variable are added to the NLP relaxation now.
909- Ipopt interface now supports warmstarts from a full primal/dual solution pair.
910- Extended data structure SCIP_ROWPREP and routines to assemble a linear inequality before it is turned into a SCIP row and
911 made it available via the API.
912- MIR procedure is now available for strengthening the Benders' optimality cut
913- SCIPbranchcandCalcLPCands() now also returns fractional variables in unbounded solutions.
914- New emphasis "benchmark" to avoid different solving paths that may come from checking remaining memory.
915- New plugin type for cut selection: users can now include their own cut selection rules, default rule moved to cutsel_hybrid.
916- New construction heuristic DPS which additionally needs a user-provided decomposition and splits the problem into several sub-SCIPs
917 according to this decomposition. The sub-SCIPs are solved and updated repeatedly until a feasible solution of the original problem is found.
920- Removed support for expression types min and max for now. Removed support for expression type sign.
921 Removed complex expression types sum, product, linear, quadratic, polynomial.
922 Removed support for parameterized expressions.
923- Added support for expression types sin, cos, and entropy. Added an expression type that stores a SCIP variable.
924- Added handling of sin and cos expressions in OSiL reader.
925- Added handling of sin, cos, and tan expressions in ZIMPL reader.
926- Added expression handler plugin type, removed user expression type.
927- Replaced expressions, expression trees, and expression graphs by a new implementation of expressions.
928- Added differentiation methods (Gradients and Hessian directions) to expressions.
929- Added integrality information to expressions.
930- Added comparison and hashing of expressions.
931- Improved simplification of expressions and identification of common subexpressions, in particular terms that appear
932 equally in several quadratic functions are now identified.
933- Expression simplification now expands powers also when the resulting exponents will be larger than 2.
934- Added table to print statistics on expression handlers.
935- Removed interval-arithmetic evaluation from expression interpreter (interfaces to automatic differentiation codes).
936- Hessians for user-provided expression handlers are not available in the NLP solver interfaces for now.
937- Sparse Hessians are now returned by expression interpreter. Removed dense Hessians.
939Constraint handlers for NLP:
940- cons_nonlinear has been completely rewritten and now handles constraints of the form lhs <= expr <= rhs, where
941 expr is an expression using the new expression type. A linear part of a nonlinear constraint is no longer distinguished.
942- Methods that work on a particular nonlinear structure are now implemented via nonlinear handlers (nlhdlr).
943 These handlers are plugins of cons_nonlinear and interact with cons_nonlinear by detecting structures in expressions and
944 providing propagation and separation mechanisms.
945- Added nlhdlr "default" as a mandatory nlhdlr: this is a nlhdlr that gets active on expressions that no other nlhdlr handles.
946 It then uses the callbacks implemented in expression handlers to provide domain propagation and linear under/overestimates.
947- Added nlhdlr for quadratic expressions: domain propagation that was previously part of cons_quadratic; separation via intersection cuts (currently disabled).
948- Added nlhdlr for bilinear expressions: collects bilinear products and provides under/overestimation of a product over a 2D-projection of the LP.
949- Added nlhdlr for convex and concave expressions: detection of convex/concave subexpressions and linear under/overestimation.
950- Added nlhdlr for quotients: detects quotients, provides specialized linear under/overestimation and domain propagation for univariate quotients.
951- Added nlhdlr for perspective reformulations: detects expressions in semi-continuous variables and tightens linear
952 under/overestimates of these expressions by applying a perspective transformation.
953- Added nlhdlr for second-order cones: detects second-order cone constraints (as ||x|| <= t or a quadratic that can written like that) and
954 separates on a disaggregated reformulation (similar to cons_soc previously).
955- Removed constraint handlers abspower, bivariate, quadratic, and soc.
956- Removed simplification of duplicate abspower constraints for now.
957 Removed simplification of abspower constraints with loose variables.
958 Removed resolving of domain propagation (ConsResProp callback) and conflict analysis for abspower constraints.
959 Removed propagation of varbounds for variables of abspower constraints.
960 Removed reformulation of abs(x)^p * x into signpower expression for now.
961- Removed reformulation of SOC constraints when adding to the NLP.
962 Removed possibility to add linearizations a la Glineur or BenTal&Nemirovski for SOC constraints.
963- Removed possibility to disaggregate quadratic constraints.
964 Removed lifted tangent inequalities for bilinear terms in quadratic constraints.
965 Removed option to project LP solution onto feasible region of a quadratic constraint via interior point or gauge function.
966 Removed handling of unbounded LPs when enforcing quadratic constraints.
967- Removed construction of cuts from interval gradients for nonlinear constraints.
968 Removed possibility to pretend that all nonlinear constraints are convex.
969 Removed possibility to create local or non-initial nonlinear constraints for now.
970- Removed explicit reformulation of nonlinear constraints in presolve.
971 An extended formulation is now generated implicitly and used to construct the LP relaxation,
972 but the original formulation is used to check feasibility, propagate variable domains, etc.
973 Variables that are added for the extended formulation are now marked as relaxation-only.
974- Improved locking of nonlinear variables in nonlinear constraints by taking monotonicity into account.
975- Improved mechanisms to detect and handle structures in nonlinear constraints, which allows for several algorithms
976 to work simultaneously on equal or overlapping expressions.
977- Improved linearization of (sums of) products of binary variables, e.g., clique information is now taken into account.
978 Removed option to linearize products between a binary and a non-binary variable.
979- Nonlinear constraints with the same function (but possibly different left- or right-hand-side) are now merged.
980- When a variable appears in only one concave less-or-equal constraint, it will be fixed to one of its bounds in more cases now.
981- New branching rule for variables in nonlinear constraints (implemented in cons_nonlinear) that scores candidates
982 based on constraint violation, variable type, and pseudo-costs simultaneously.
983- Added tables to print statistics of nonlinear constraint handler and nonlinear handlers.
985Performance improvements
986------------------------
988- Use the objective cutoff row as base row for separation in sepa_aggregation.c.
989- Separate lifted cover cuts based on newer lifting function of Letchford and Souli (2019) in sepa_aggregation.c.
990- In-tree restarts due to tree size estimation have been made compatible with orbital fixing.
991- Improved upgrade of orbisacks to packing/partitioning orbitopes.
992- Improved running time of symresack cover separation.
993- Improved propagation algorithm for orbisack and symresack.
994- Improved handling for expressions of type signpower in CppAD interface by making use of CppADs conditional expressions.
995- Faster reevaluation of Hessian for quadratic expressions in CppAD interface.
996- Enabled optimization of taped expressions in the CppAD interface.
997- Sparse Hessian evaluation for expressions with sparse Hessian in the CppAD interface.
998- Disabled branching on variables that are added for the extended formulation of a nonlinear constraint.
999- Prefer branching on variables in nonconvex terms of nonlinear constraints also if a cut could be generated but would yield a small reduction in the convexification gap only.
1000- When violations of nonlinear constraints are tiny, the feasibility tolerance for the LP relaxation may now be reduced temporarily to allow for cuts to have an effect.
1001- Improved under/overestimation of multidimensional vertex-polyhedral (e.g., multilinear or concave) functions by use of scaling and keeping the cut-generating LP around.
1002- Products in nonlinear constraints are no longer disaggregated for the extended formulation.
1003- No longer relax bounds of integral variables when computing bounds on activity in nonlinear constraints.
1004- Revised and improved Ipopt interface.
1005- Revised and improved subNLP primal heuristic, in particular choice of iteration limit and starting condition and reuse of subSCIP.
1006- Merge strongcg into the gomory separator to avoid computing the same base equality twice. The files
1007 sepa_strongcg.{h|c} have been removed.
1008- The RENS neighborhood in ALNS now fixes fractional variables if necessary for reaching its target fixing rate.
1009- Use cpsolver emphasis in sepa_rapidlearning.
1010- If decomposition/maxgraphedge = 0, the computation of the block graph is completely turned off.
1011- Fixed a performance bug in cons_integral.c where rounding information was passed incorrectly to the generic diving algorithm.
1013Examples and applications
1014-------------------------
1016- Add c++ Sudoku example
1017- Removed circle.c and renamed string.c to spring.c in CallableLibrary example.
1018- SCIP-Jack (Steiner tree application):
1019 Most files have been modified and many new ones have been added (code base more than doubled).
1020 Two new problem classes are supported: maximum-weight connected subgraph problem with budget constraints, partial-terminal node-weighted Steiner tree problem.
1021 Major performance improvements accross all problem classes that are supported.
1026### New and changed callbacks
1028- extend SEPAEXEC{LP,SOL} callbacks by parameter "depth", which should be used within separation instead of SCIPgetCurrentDepth()
1029- extend SCIPseparateSolCutpool() by parameter "pretendroot", which is passed to SCIPcutpoolSeparate() instead of SCIPtreeGetCurrentDepth(scip->tree) == 0
1030- removed SCIP_DECL_EXPRGRAPHVARADDED, SCIP_DECL_EXPRGRAPHVARREMOVE, SCIP_DECL_EXPRGRAPHVARCHGIDX
1031- removed SCIP_DECL_USEREXPRESTIMATE, SCIP_DECL_USEREXPREVAL, SCIP_DECL_USEREXPRINTEVAL, SCIP_DECL_USEREXPRCURV, SCIP_DECL_USEREXPRPROP, SCIP_DECL_USEREXPRCOPYDATA, SCIP_DECL_USEREXPRFREEDATA, SCIP_DECL_USEREXPRPRINT
1032- added SCIP_DECL_EXPR_OWNERFREE, SCIP_DECL_EXPR_OWNERPRINT, SCIP_DECL_EXPR_OWNEREVALACTIVITY, SCIP_DECL_EXPR_OWNERCREATE
1033- added SCIP_DECL_EXPR_INTEVALVAR, SCIP_DECL_EXPR_MAPEXPR
1034- added SCIP_DECL_EXPRCOPYHDLR, SCIP_DECL_EXPRFREEHDLR, SCIP_DECL_EXPRCOPYDATA, SCIP_DECL_EXPRFREEDATA, SCIP_DECL_EXPRPRINT, SCIP_DECL_EXPRPARSE, SCIP_DECL_EXPRCURVATURE, SCIP_DECL_EXPRMONOTONICITY, SCIP_DECL_EXPRINTEGRALITY, SCIP_DECL_EXPRHASH, SCIP_DECL_EXPRCOMPARE, SCIP_DECL_EXPREVAL, SCIP_DECL_EXPRBWDIFF, SCIP_DECL_EXPRFWDIFF, SCIP_DECL_EXPRBWFWDIFF, SCIP_DECL_EXPRINTEVAL, SCIP_DECL_EXPRESTIMATE, SCIP_DECL_EXPRINITESTIMATES, SCIP_DECL_EXPRSIMPLIFY, SCIP_DECL_EXPRREVERSEPROP
1035- removed SCIP_DECL_QUADCONSUPGD
1036- added SCIP_DECL_VERTEXPOLYFUN
1037- added argument nvarexprs to SCIP_DECL_NONLINCONSUPGD to inform upgrade method about number of variables in constraint
1038- removed SCIP_DECL_EXPRGRAPHNODEREFORM
1039- added SCIP_DECL_NLHDLRCOPYHDLR, SCIP_DECL_NLHDLRFREEHDLRDATA, SCIP_DECL_NLHDLRFREEEXPRDATA, SCIP_DECL_NLHDLRINIT, SCIP_DECL_NLHDLREXIT, SCIP_DECL_NLHDLRDETECT, SCIP_DECL_NLHDLREVALAUX, SCIP_DECL_NLHDLRINTEVAL, SCIP_DECL_NLHDLRREVERSEPROP, SCIP_DECL_NLHDLRINITSEPA, SCIP_DECL_NLHDLREXITSEPA, SCIP_DECL_NLHDLRENFO, SCIP_DECL_NLHDLRESTIMATE
1040- replaced BMS_BLKMEM* blkmem argument of SCIP_DECL_NLPICOPY by SCIP* scip, removed targetnlpi argument
1041- added SCIP* scip and SCIP_NLPIDATA** nlpidata arguments to SCIP_DECL_NLPIFREE
1042- added SCIP* scip to SCIP_DECL_NLPIGETSOLVERPOINTER, SCIP_DECL_NLPICREATEPROBLEM, SCIP_DECL_NLPIFREEPROBLEM, SCIP_DECL_NLPIGETPROBLEMPOINTER, SCIP_DECL_NLPIADDVARS, SCIP_DECL_NLPIADDCONSTRAINTS, SCIP_DECL_NLPISETOBJECTIVE, SCIP_DECL_NLPICHGVARBOUNDS, SCIP_DECL_NLPICHGCONSSIDES, SCIP_DECL_NLPIDELVARSET, SCIP_DECL_NLPIDELCONSSET, SCIP_DECL_NLPICHGLINEARCOEFS, SCIP_DECL_NLPICHGOBJCONSTANT, SCIP_DECL_NLPISETINITIALGUESS, SCIP_DECL_NLPISOLVE, SCIP_DECL_NLPIGETSOLSTAT, SCIP_DECL_NLPIGETTERMSTAT, SCIP_DECL_NLPIGETSOLUTION, SCIP_DECL_NLPIGETSTATISTICS
1043- replaced SCIP_DECL_NLPICHGEXPRTREE by SCIP_DECL_NLPICHGEXPR
1044- removed nquadelems, quadelems, exprvaridxs arguments from SCIP_DECL_NLPIADDCONSTRAINTS, changed exprtrees argument to exprs
1045- removed nquadelems, quadelems, exprvaridxs arguments from SCIP_DECL_NLPISETOBJECTIVE, changed exprtree argument to expr
1046- removed SCIP_DECL_NLPICHGQUADCOEFS, SCIP_DECL_NLPICHGNONLINCOEF, SCIP_DECL_NLPISETMESSAGEHDLR
1047- added SCIP_NLPIPROBLEM* problem to SCIP_DECL_NLPIGETSOLVERPOINTER
1049### Deleted and changed API methods
1051- When calling SCIPdelVar() in the SCIP_STAGE_PROBLEM stage, it is now documented as the user's responsibility to ensure
1052 the variable is not present in any constraints. Otherwise, SCIPsolve() now returns SCIP_INVALIDDATA.
1053- removed SCIPselectCuts(), replaced by SCIPselectCutsHybrid() of the hybrid cut selector plugin
1054- If SCIPvarMarkRelaxationOnly() is called for a variable, then this now need to happen before the
1055 variable is added to the transformed problem (SCIPaddVar()).
1056 SCIPvarMarkRelaxationOnly() will automatically call SCIPvarMarkDeletable().
1057- SCIPcomputeOrbitsFilterSym() and SCIPcomputeComponentsSym(): Type of argument componentblocked
1058 changed from SCIP_Shortbool* to unsigned*.
1059- removed SCIPsetParam()
1060- SCIPcreateConsOrbitope() and SCIPcreateConsBasicOrbitope() have two new arguments "usedynamicprop"
1061 and "mayinteract" to encode whether a dynamic reordering of the orbitope rows shall be used in
1062 full orbitope propagation and whether the orbitope might interact with other symmetry handling
1063 methods, respectively.
1064- internal function SCIPgetPropertiesPerm() has been replaced by SCIPisInvolutionPerm()
1065- internal function SCIPgenerateOrbitopeVarsMatrix() has new arguments "storelexorder", "lexorder",
1066 "nvarsorder", "maxnvarsorder" to compute and store the lexicographic order defined by an orbitope
1067- renamed SCIPcomputeArraysIntersection() and SCIPcomputeArraysSetminus() to
1068 SCIPcomputeArraysIntersectionInt() and SCIPcomputeArraysSetminusInt(), respectively, and changed
1069 their return type from SCIP_RETCODE (which _always_ was SCIP_OKAY) to void
1070- removed SCIPincludeDialogDefault(), use SCIPincludeDialogDefaultBasic() instead and check whether you also need SCIPincludeDialogDefaultSet() and SCIPincludeDialogDefaultFix()
1071- removed exprint argument from SCIPaddNlRowGradientBenderscutOpt()
1072- added copyexprhdlrs argument to SCIPcopyPlugins() (19th position)
1073- added copycutselectors argument to SCIPcopyPlugins() (10th position)
1074- removed refpoint argument from SCIPaddSquareSecant()
1075- added argument exprdata to SYMcomputeSymmetryGenerators()
1076- removed SCIPconsNonlinearGetRhs(), SCIPconsNonlinearGetLhs(), SCIPconsNonlinearAddLinearCoef()
1077- removed arguments timelimit, minimprove, itercontingent, and iterused from SCIPapplyHeurSubNlp()
1078- removed SCIPresolveSolHeurSubNlp(), SCIPgetSubScipHeurSubNlp(), SCIPgetVarMappingScip2SubScipHeurSubNlp(), SCIPgetVarMappingSubScip2ScipHeurSubNlp()
1079- SCIPlockVarCons() and SCIPunlockVarCons() are now allowed in stage TRANSFORMED as well
1080- Added functions SCIPsetSepaIsParentsepa(), SCIPsetSepaParentsepa() [in scip_sepa.h], SCIPsepaSetIsParentsepa(), SCIPsepaSetParentsepa() [in sepa.h],
1081 SCIPsepaIsParentsepa(), SCIPsepaGetParentsepa() [in pub_sepa.h]
1082- Added function SCIPpruneTree() to immediately delete nodes that were marked to be deleted with SCIPcutoffNode
1085- SCIPhasNLPContinuousNonlinearity() now returns SCIP_RETCODE and has additional argument result
1086- removed SCIPnlrowGetNQuadVars(), SCIPnlrowGetQuadVars(), SCIPnlrowSearchQuadVar(), SCIPnlrowGetNQuadElems(), SCIPnlrowGetQuadElems(), SCIPnlrowGetQuadData()
1087- renamed SCIPnlrowGetExprtree() to SCIPnlrowGetExpr() and changed return type to SCIP_EXPR*
1088- removed arguments nquadvars, quadvars, nquadelems, quadelems from SCIPcreateNlRow(); argument expr(ession) is now of type SCIP_EXPR*
1089- removed SCIPaddQuadVarToNlRow(), SCIPaddQuadVarsToNlRow(), SCIPaddQuadElementToNlRow(), SCIPaddQuadElementsToNlRow(), SCIPchgNlRowQuadElement(), SCIPsetNlRowExprtreeParam(), SCIPsetNlRowExprtreeParams()
1090- renamed SCIPsetNlRowExprtree() to SCIPsetNlRowExpr() and changed type of expr(tree) argument to SCIP_EXPR*
1091- SCIPenableNLP() is no longer allowed in stages INITSOLVE and SOLVING
1092- removed SCIPaddLinearConsToNlpHeurSubNlp()
1093- SCIPhasNLPSolution() now returns true also if a infeasible solution to the NLP exists; SCIPcreateNLPSol() can now also be used when only an infeasible solution to the NLP exists
1094- renamed SCIPsolveNLP() to SCIPsolveNLPParam() and added parameter SCIP_NLPPARAM param
1095- removed SCIPsolveDiveNLP(), use SCIPsolveNLPParam() instead
1098- removed SCIPnlpiCopy(), SCIPnlpiFree(), SCIPnlpiChgQuadCoefs(), SCIPnlpiChgNonlinCoef(), SCIPnlpiSetMessageHdlr()
1099- removed SCIPnlpiCreate() from public API, use SCIPincludeNlpi() instead
1100- removed SCIPnlpiGetSolverPointer() from public API, use SCIPgetNlpiSolverPointer() instead
1101- removed SCIPnlpiCreateProblem() from public API, use SCIPcreateNlpiProblem() instead
1102- removed SCIPnlpiFreeProblem() from public API, use SCIPfreeNlpiProblem() instead
1103- removed SCIPnlpiGetProblemPointer() from public API, use SCIPgetNlpiProblemPointer() instead
1104- removed SCIPnlpiAddVars() from public API, use SCIPaddNlpiVars() instead
1105- removed SCIPnlpiAddConstraints() from public API, use SCIPaddNlpiConstraints() instead
1106- removed SCIPnlpiSetObjective() from public API, use SCIPsetNlpiObjective() instead
1107- removed SCIPnlpiChgVarBounds() from public API, use SCIPchgNlpiVarBounds() instead
1108- removed SCIPnlpiChgConsSides() from public API, use SCIPchgNlpiConsSides() instead
1109- removed SCIPnlpiDelVarSet() from public API, use SCIPdelNlpiVarSet() instead
1110- removed SCIPnlpiDelConsSet() from public API, use SCIPdelNlpiConsSet() instead
1111- removed SCIPnlpiChgLinearCoefs() from public API, use SCIPchgNlpiLinearCoefs() instead
1112- removed SCIPnlpiChgExprtree() from public API, use SCIPchgNlpiExpr() instead
1113- removed SCIPnlpiChgObjConstant() from public API, use SCIPchgNlpiObjConstant() instead
1114- removed SCIPnlpiSetInitialGuess() from public API, use SCIPsetNlpiInitialGuess() instead
1115- removed SCIPnlpiSolve() from public API, use SCIPsolveNlpiParam() instead
1116- removed SCIPnlpiGetSolstat() from public API, use SCIPgetNlpiSolstat() instead
1117- removed SCIPnlpiGetTermstat() from public API, use SCIPgetNlpiTermstat() instead
1118- removed SCIPnlpiGetSolution() from public API, use SCIPgetNlpiSolution() instead
1119- removed SCIPnlpiGetStatistics() from public API, use SCIPgetNlpiStatistics() instead
1120- removed SCIPnlpiGetWarmstartSize()
1121- removed SCIPnlpiGetWarmstartMemo()
1122- removed SCIPnlpiSetWarmstartMemo()
1123- removed SCIPnlpiGetIntPar()
1124- removed SCIPnlpiSetIntPar()
1125- removed SCIPnlpiGetRealPar()
1126- removed SCIPnlpiSetRealPar()
1127- removed SCIPnlpiGetStringPar(),
1128- removed SCIPnlpiSetStringPar()
1129- removed SCIPnlpiSetPriority() from public API, use SCIPsetNlpiPriority() instead
1130- removed argument nlpi from SCIPincludeNlpi() and added name, description, priority,
1131 nlpicopy, nlpifree, nlpigetsolverpointer, nlpicreateproblem, nlpifreeproblem, nlpigetproblempointer, nlpiaddvars, nlpiaddconstraints, nlpisetobjective, nlpichgvarbounds, nlpichgconssides, nlpidelvarset, nlpidelconsset, nlpichglinearcoefs, nlpichgexpr, nlpichgobjconstant, nlpisetinitialguess, nlpisolve, nlpigetsolstat, nlpigettermstat, nlpigetsolution, nlpigetstatistics, nlpidata
1132- removed SCIPcreateNlpSolverAll(), use SCIPincludeNlpSolverAll() instead
1133- removed SCIPcreateNlpSolverFilterSQP(), use SCIPincludeNlpSolverFilterSQP() instead
1134- removed SCIPcreateNlpSolverIpopt(), use SCIPincludeNlpSolverIpopt() instead
1135- removed SCIPcreateNlpSolverWorhp(), use SCIPincludeNlpSolverWorhp() instead
1136- replaced argument BMS_BLKMEM* blkmem of SCIPnlpiOracleCreate() by SCIP* scip
1137- added argument SCIP* scip to SCIPnlpiOracleFree(), SCIPnlpiOracleSetProblemName(), SCIPnlpiOracleAddVars(), SCIPnlpiOracleAddConstraints(), SCIPnlpiOracleSetObjective(), SCIPnlpiOracleChgVarBounds(), SCIPnlpiOracleChgConsSides(), SCIPnlpiOracleDelVarSet(), SCIPnlpiOracleDelConsSet(), SCIPnlpiOracleChgLinearCoefs(), SCIPnlpiOracleChgObjConstant(), SCIPnlpiOracleGetEvalCapability(), SCIPnlpiOracleEvalObjectiveValue(), SCIPnlpiOracleEvalConstraintValue(), SCIPnlpiOracleEvalConstraintValues(), SCIPnlpiOracleEvalObjectiveGradient(), SCIPnlpiOracleEvalConstraintGradient(), SCIPnlpiOracleGetJacobianSparsity(), SCIPnlpiOracleEvalJacobian(), SCIPnlpiOracleGetHessianLagSparsity(), SCIPnlpiOracleEvalHessianLag(), SCIPnlpiOraclePrintProblem(), SCIPnlpiOraclePrintProblemGams()
1138- removed arguments nquadelems, quadelems, exprvaridxs, exprtrees from SCIPnlpiOracleAddConstraints(), added argument SCIP_EXPR** exprs
1139- removed arguments nquadelems, quadelems, exprvaridxs, exprtree from SCIPnlpiOracleSetObjective(), added argument SCIP_EXPR* expr
1140- replaced arguments isnewx of SCIPnlpiOracleEvalHessianLag() by two arguments isnewx_obj and isnewx_cons
1141- removed SCIPnlpiOracleChgExprtree(), use SCIPnlpiOracleChgExpr() instead
1142- removed SCIPnlpiOracleSetInfinity(), SCIPnlpiOracleGetInfinity(), SCIPnlpiOracleChgQuadCoefs(), SCIPnlpiOracleChgExprParam(), SCIPnlpiOracleGetMaxDegree()
1143- removed SCIPnlpiOracleGetVarDegree() and SCIPnlpiOracleGetVarDegrees(), use SCIPnlpiOracleIsVarNonlinear() and SCIPnlpiOracleGetVarCounts(), respectively, instead
1144- removed SCIPnlpiOracleGetConstraintDegree(), use SCIPnlpiOracleIsConstraintNonlinear() instead
1145- removed argument messagehdlr from SCIPnlpiOraclePrintProblem() and SCIPnlpiOraclePrintProblemGams()
1146- removed SCIPcreateNlpiProb(), use SCIPcreateNlpiProblemFromNlRows() instead
1147- renamed SCIPupdateNlpiProb() to SCIPupdateNlpiProblem() and moved into scip_nlpi.{h,c}
1148- renamed SCIPaddNlpiProbRows() to SCIPaddNlpiProblemRows() and moved into scip_nlpi.{h,c}
1149- removed SCIPsetModifiedDefaultSettingsIpopt()
1150- removed SCIPgetIpoptApplicationPointerIpopt(), use SCIPgetNlpiSolverPointer() instead
1151- removed SCIPnlpStatisticsCreate(), SCIPnlpStatisticsFree(), SCIPnlpStatisticsGetNIterations(), SCIPnlpStatisticsGetTotalTime(), SCIPnlpStatisticsSetNIterations(), SCIPnlpStatisticsSetTotalTime(), the struct is public now
1152- renamed LapackDsyev() to SCIPcallLapackDsyevIpopt()
1153- renamed SCIPsolveLinearProb() to SCIPsolveLinearEquationsIpopt()
1155Expression interpreter:
1156- removed functions that operated with SCIPInterval
1157- changed first argument of SCIPexprintCreate() to SCIP*
1158- added SCIP* as first argument to SCIPexprintFree()
1159- added SCIP* as first argument to SCIPexprintCompile(), changed third argument to SCIP_EXPR*, added fourth argument SCIP_EXPRINTDATA**
1160- added arguments SCIP*, SCIP_EXPRINT*, and SCIP_EXPR* as first arguments to SCIPexprintFreeData()
1161- renamed SCIPexprintGetExprtreeCapability() to SCIPexprintGetExprCapability();
1162 added SCIP* as first argument, changed third argument to SCIP_EXPR*, added fourth argument SCIP_EXPRINTDATA*
1163- removed SCIPexprintNewParametrization()
1164- SCIPexprintEval(): added SCIP* as first argument, changed third argument to SCIP_EXPR*, added fourth argument SCIP_EXPRINTDATA*
1165- removed SCIPexprintEvalInt()
1166- SCIPexprintGrad(): added SCIP* as first argument, changed third argument to SCIP_EXPR*, added fourth argument SCIP_EXPRINTDATA*
1167- removed SCIPexprintGradInt()
1168- removed SCIPexprintHessianSparsityDense() and SCIPexprintHessianDense, use SCIPexprintHessianSparsity() and SCIPexprintHessian() instead
1171- removed SCIPexpropGetName(), use SCIPexprhdlrGetName() instead
1172- removed SCIPexpropGetNChildren()
1173- removed SCIPexprGetOperator(), use SCIPexprGetHdlr() instead
1174- removed SCIPexprGetOpIndex(), SCIPexprGetOpReal(), SCIPexprGetOpData(), use SCIPexprGetData() instead
1175- removed SCIPexprGetRealPowerExponent(), SCIPexprGetIntPowerExponent(), SCIPexprGetSignPowerExponent(), use SCIPgetExponentExprPow() instead
1176- removed SCIPexprGetLinearCoefs(), SCIPexprGetLinearConstant(), use SCIPgetCoefsExprSum() and SCIPgetConstantExprSum() instead
1177- removed SCIPexprGetQuadElements(), SCIPexprGetQuadConstant(), SCIPexprGetQuadLinearCoefs(), SCIPexprGetNQuadElements(), use SCIPexprGetQuadraticData(), SCIPexprGetQuadraticQuadTerm(), SCIPexprGetQuadraticBilinTerm() instead
1178- removed SCIPexprGetMonomials(), SCIPexprGetNMonomials, SCIPexprGetPolynomialConstant(), SCIPexprGetMonomialCoef(), SCIPexprGetMonomialNFactors(), SCIPexprGetMonomialChildIndices(), SCIPexprGetMonomialExponents()
1179- removed SCIPexprGetUserData(), SCIPexprHasUserEstimator(), SCIPexprGetUserEvalCapability()
1180- removed SCIPexprCreate(), use SCIPcreateExpr() instead
1181- removed SCIPexprCopyDeep(), use SCIPduplicateExpr() instead
1182- removed SCIPexprFreeDeep(), use SCIPreleaseExpr() instead
1183- removed SCIPexprFreeShallow()
1184- removed SCIPexprAdd(), SCIPexprMulConstant()
1185- removed SCIPexprCreateLinear(), use SCIPcreateExprSum() instead
1186- replaced SCIPexprAddToLinear() by SCIPappendExprSumExpr()
1187- replaced SCIPexprCreateQuadratic() by SCIPcreateExprQuadratic()
1188- removed SCIPexprSortQuadElems()
1189- removed SCIPexprCreatePolynomial(), SCIPexprAddMonomials(), SCIPexprChgPolynomialConstant(), SCIPexprMultiplyPolynomialByConstant(), SCIPexprMultiplyPolynomialByMonomial(), SCIPexprMultiplyPolynomialByPolynomial(), SCIPexprPolynomialPower()
1190- removed SCIPexprMergeMonomials(), SCIPexprFreeMonomial(), SCIPexprSortMonomialFactors(), SCIPexprFindMonomialFactor(), SCIPexprAreMonomialsEqual(), SCIPexprAddMonomialFactors(), SCIPexprChgMonomialCoef(), SCIPexprMultiplyMonomialByMonomial(), SCIPexprMonomialPower(), SCIPexprMergeMonomialFactors(), SCIPexprSortMonomials()
1191- replaced SCIPexprCreateMonomial() by SCIPcreateExprMonomial()
1192- removed SCIPexprCreateUser(), use SCIPincludeExprhdlr() instead
1193- removed SCIPexprHasParam(), SCIPexprGetMaxDegree(), SCIPexprGetVarsUsage()
1194- replaced SCIPexprAreEqual() by SCIPcompareExpr()
1195- replaced SCIPexprSimplify() by SCIPsimplifyExpr()
1196- replaced SCIPexprEvalShallow() by SCIPcallExprEval()
1197- replaced SCIPexprEval() by SCIPevalExpr()
1198- replaced SCIPexprEvalIntShallow() by SCIPcallExprInteval()
1199- replaced SCIPexprEvalInt() by SCIPevalExprActivity()
1200- removed SCIPexprEvalUser(), SCIPexprEvalIntUser(), SCIPexprEstimateUser()
1201- replaced SCIPexprCheckCurvature() by SCIPcomputeExprCurvature()
1202- removed SCIPexprSubstituteVars(), use SCIPcopyExpr() instead
1203- removed SCIPexprReindexVars(), SCIPexprReindexParams()
1204- replaced SCIPexprPrint() by SCIPprintExpr()
1205- replaced SCIPexprParse() by SCIPparseExpr()
1208- removed SCIPexprtreeGetVars(), SCIPexprtreeSetVars(), SCIPexprtreeAddVars(), SCIPexprtreePrintWithNames(), SCIPexprtreeFindVar()
1209- removed SCIPexprtreeGetRoot(), SCIPexprtreeGetNVars(), SCIPexprtreeGetNParams(), SCIPexprtreeGetParamVals(), SCIPexprtreeSetParamVal(), SCIPexprtreeHasParam()
1210- removed SCIPexprtreeGetInterpreterData(), SCIPexprtreeSetInterpreterData(), SCIPexprtreeFreeInterpreterData()
1211- removed SCIPexprtreeGetMaxDegree()
1212- removed SCIPexprtreeEval(), use SCIPevalExpr() instead
1213- removed SCIPexprtreeEvalInt(), use SCIPevalExprActivity() instead
1214- removed SCIPexprtreePrint(), use SCIPprintExpr() instead
1215- removed SCIPexprtreeCreate()
1216- removed SCIPexprtreeCopy(), use SCIPduplicateExpr() instead
1217- removed SCIPexprtreeFree(), use SCIPreleaseExpr() instead
1218- removed SCIPexprtreeSetParams(), SCIPexprtreeGetVarsUsage()
1219- removed SCIPexprtreeSimplify(), use SCIPsimplifyExpr() instead
1220- removed SCIPexprtreeAddExpr()
1221- removed SCIPexprtreeCheckCurvature(), use SCIPcomputeExprCurvature() instead
1222- removed SCIPexprtreeSubstituteVars(), use SCIPcopyExpr() instead
1223- removed SCIPquadelemSort(), SCIPquadelemSortedFind(), SCIPquadelemSqueeze()
1226- removed SCIPexprgraphCaptureNode(), use SCIPcaptureExpr() instead
1227- removed SCIPexprgraphIsNodeEnabled()
1228- removed SCIPexprgraphGetNodeNChildren(), use SCIPexprGetNChildren() instead
1229- removed SCIPexprgraphGetNodeChildren(), use SCIPexprGetChildren() instead
1230- removed SCIPexprgraphGetNodeNParents(), SCIPexprgraphGetNodeParents(), SCIPexprgraphGetNodeDepth(), SCIPexprgraphGetNodePosition()
1231- removed SCIPexprgraphGetNodeOperator(), use SCIPexprGetHdlr() instead
1232- removed SCIPexprgraphGetNodeOperatorIndex(), SCIPexprgraphGetNodeOperatorReal(), use SCIPexprGetData() instead
1233- removed SCIPexprgraphGetNodeVar(), use SCIPgetVarExprVar() instead
1234- removed SCIPexprgraphGetNodeRealPowerExponent(), SCIPexprgraphGetNodeIntPowerExponent(), SCIPexprgraphGetNodeSignPowerExponent(), use SCIPgetExponentExprPow() instead
1235- removed SCIPexprgraphGetNodeLinearCoefs(), SCIPexprgraphGetNodeLinearConstant(), use SCIPgetCoefsExprSum(), SCIPgetConstantExprSum() instead
1236- removed SCIPexprgraphGetNodeQuadraticConstant(), SCIPexprgraphGetNodeQuadraticLinearCoefs(), SCIPexprgraphGetNodeQuadraticQuadElements(), SCIPexprgraphGetNodeQuadraticNQuadElements(), use SCIPexprGetQuadraticData(), SCIPexprGetQuadraticQuadTerm(), SCIPexprGetQuadraticBilinTerm() instead
1237- removed SCIPexprgraphGetNodePolynomialMonomials(), SCIPexprgraphGetNodePolynomialNMonomials(), SCIPexprgraphGetNodePolynomialConstant(), SCIPexprgraphGetNodePolynomialMonomialCurvature()
1238- removed SCIPexprgraphGetNodeUserData(), SCIPexprgraphHasNodeUserEstimator()
1239- removed SCIPexprgraphGetNodeBounds(), use SCIPexprGetActivity() instead
1240- removed SCIPexprgraphGetNodeVal(), use SCIPexprGetEvalValue() instead
1241- removed SCIPexprgraphGetNodeCurvature(), use SCIPexprGetCurvature() instead
1242- removed SCIPexprgraphCreateNode()
1243- removed SCIPexprgraphCreateNodeLinear(), use SCIPcreateExprSum() instead
1244- removed SCIPexprgraphCreateNodeQuadratic(), use SCIPcreateExprQuadratic() instead
1245- removed SCIPexprgraphCreateNodePolynomial(), SCIPexprgraphNodePolynomialAddMonomials()
1246- removed SCIPexprgraphCreateNodeUser(), removed SCIPexprgraphNodeSplitOffLinear(), SCIPexprgraphMoveNodeParents()
1247- removed SCIPexprgraphReleaseNode(), use SCIPreleaseExpr() instead
1248- removed SCIPexprgraphFreeNode(), use SCIPreleaseExpr() instead
1249- removed SCIPexprgraphEnableNode(), SCIPexprgraphDisableNode()
1250- removed SCIPexprgraphHasNodeSibling(), SCIPexprgraphAreAllNodeChildrenVars(), SCIPexprgraphHasNodeNonlinearAncestor()
1251- removed SCIPexprgraphPrintNode(), SCIPprintExpr() instead
1252- removed SCIPexprgraphTightenNodeBounds()
1253- removed SCIPexprgraphUpdateNodeBoundsCurvature(), use SCIPevalExprActivity() and SCIPcomputeExprCurvature() instead
1254- removed SCIPexprgraphGetDepth(), SCIPexprgraphGetNNodes(), SCIPexprgraphGetNodes(), SCIPexprgraphGetNVars(), SCIPexprgraphGetVars()
1255- removed SCIPexprgraphGetVarNodes(), SCIPexprgraphSetVarNodeValue(), SCIPexprgraphSetVarsBounds(), SCIPexprgraphSetVarBounds(), SCIPexprgraphSetVarNodeBounds(), SCIPexprgraphSetVarNodeLb(), SCIPexprgraphSetVarNodeUb(), SCIPexprgraphGetVarsBounds()
1256- removed SCIPexprgraphCreate(), SCIPexprgraphFree()
1257- removed SCIPexprgraphAddNode(), SCIPexprgraphAddVars(), SCIPexprgraphAddConst(), SCIPexprgraphAddExprtreeSum()
1258- removed SCIPexprgraphReplaceVarByLinearSum(), SCIPexprgraphFindVarNode(), SCIPexprgraphFindConstNode()
1259- replaced SCIPexprgraphPrintDot() by SCIPprintExprDotInit[2](), SCIPprintExprDot(), SCIPprintExprDotFinal()
1260- removed SCIPexprgraphEval(), use SCIPevalExpr() instead
1261- removed SCIPexprgraphPropagateVarBounds(), SCIPexprgraphPropagateNodeBounds()
1262- removed SCIPexprgraphCheckCurvature(), use SCIPcomputeExprCurvature() instead
1263- removed SCIPexprgraphSimplify(), use SCIPsimplifyExpr() instead
1264- removed SCIPexprgraphGetTree(), SCIPexprgraphGetSeparableTrees(), SCIPexprgraphGetSubtreeVarsUsage(), SCIPexprgraphGetSumTreesNSummands(), SCIPexprgraphGetSumTrees()
1266Constraint handlers for NLP:
1267- removed SCIPincludeConshdlrAbspower()
1268- deprecated SCIPcreateConsAbspower() and SCIPcreateConsBasicAbspower(), use SCIPcreateConsBasicSignpowerNonlinear() instead
1269- deprecated SCIPgetNlRowAbspower(), use SCIPgetNlRowNonlinear() instead
1270- removed SCIPgetNonlinearVarAbspower(), SCIPgetLinearVarAbspower(), SCIPgetExponentAbspower(), SCIPgetOffsetAbspower(), SCIPgetCoefLinearAbspower(), SCIPgetLhsAbspower(), SCIPgetRhsAbspower()
1271- removed SCIPgetViolationAbspower(), use SCIPgetAbsViolationNonlinear() instead
1272- removed SCIPisConvexAbspower(), use SCIPhasExprCurvature() instead
1273- removed SCIPincludeConshdlrBivariate(), SCIPcreateConsBivariate(), SCIPcreateConsBasicBivariate()
1274- removed SCIPgetLinearVarBivariate(), SCIPgetLinearCoefBivariate(), SCIPgetExprtreeBivariate(), SCIPgetLhsBivariate(), SCIPgetRhsBivariate()
1275- removed SCIPincludeConshdlrQuadratic(), use SCIPincludeNlhdlrQuadratic() instead
1276- removed SCIPincludeQuadconsUpgrade()
1277- removed SCIPcreateConsQuadratic2(), SCIPcreateConsBasicQuadratic2()
1278- deprecated SCIPcreateConsBasicQuadratic(), use SCIPcreateConsBasicQuadraticNonlinear() instead
1279- deprecated SCIPcreateConsBasicQuadratic(), use SCIPcreateConsQuadraticNonlinear() instead
1280- deprecated SCIPaddConstantQuadratic(), use SCIPgetLhsNonlinear() and SCIPgetRhsNonlinear() instead
1281- deprecated SCIPaddLinearVarQuadratic(), use SCIPaddLinearVarNonlinear() instead
1282- deprecated SCIPaddQuadVarQuadratic(), use SCIPaddLinearVarNonlinear() and SCIPaddExprNonlinear() instead
1283- deprecated SCIPaddQuadVarLinearCoefQuadratic(), use SCIPaddLinearVarNonlinear() instead
1284- deprecated SCIPaddSquareCoefQuadratic(), use SCIPaddExprNonlinear() instead
1285- deprecated SCIPaddBilinTermQuadratic(), use SCIPaddExprNonlinear() instead
1286- deprecated SCIPchgLhsQuadratic(), use SCIPgetLhsNonlinear() instead
1287- deprecated SCIPchgRhsQuadratic(), use SCIPgetRhsNonlinear() instead
1288- deprecated SCIPgetNlRowQuadratic(), use SCIPgetNlRowNonlinear() instead
1289- removed SCIPgetNLinearVarsQuadratic(), SCIPgetLinearVarsQuadratic(), SCIPgetCoefsLinearVarsQuadratic(), SCIPgetNQuadVarTermsQuadratic(), SCIPgetQuadVarTermsQuadratic(), SCIPsortQuadVarTermsQuadratic(), SCIPfindQuadVarTermQuadratic(), SCIPgetNBilinTermsQuadratic(), SCIPgetBilinTermsQuadratic(), SCIPgetLhsQuadratic(), SCIPgetRhsQuadratic()
1290- removed SCIPgetLinvarMayDecreaseQuadratic(), SCIPgetLinvarMayIncreaseQuadratic()
1291- removed SCIPcheckCurvatureQuadratic() and SCIPisConvexConsQuadratic(), use SCIPcomputeExprQuadraticCurvature() instead
1292- removed SCIPisConvexQuadratic(), SCIPisConcaveQuadratic()
1293- removed SCIPgetViolationQuadratic() and SCIPgetFeasibilityQuadratic(), use SCIPgetAbsViolationNonlinear() instead
1294- removed SCIPisLinearLocalQuadratic(), SCIPaddToNlpiProblemQuadratic()
1295- removed SCIPchgLinearCoefQuadratic(), SCIPchgSquareCoefQuadratic(), SCIPchgBilinCoefQuadratic()
1296- renamed SCIPgetNAllBilinearTermsQuadratic() to SCIPgetNBilinTermsNonlinear() and changed argument from SCIP* to SCIP_CONSHDLR*
1297- renamed SCIPgetAllBilinearTermsQuadratic() to SCIPgetBilinTermsNonlinear() and replaced arguments by SCIP_CONSHDLR* and changed return type to SCIP_CONSNONLINEAR_BILINTERM*
1298- removed SCIPaddBilinearIneqQuadratic(), use SCIPinsertBilinearTermImplicitNonlinear() instead
1299- renamed SCIPcreateConsQuadratic() to SCIPcreateConsQuadraticNonlinear() and removed argument stickingatnode
1300- removed SCIPincludeConshdlrSOC()
1301- replaced SCIPcreateConsBasicSOC() by SCIPcreateConsBasicSOCNonlinear()
1302- deprecated SCIPcreateConsSOC(), use SCIPcreateConsBasicSOCNonlinear() instead
1303- deprecated SCIPgetNlRowSOC(), use SCIPgetNlRowNonlinear() instead
1304- removed SCIPgetNLhsVarsSOC(), SCIPgetLhsVarsSOC(), SCIPgetLhsCoefsSOC(), SCIPgetLhsOffsetsSOC(), SCIPgetLhsConstantSOC(), SCIPgetRhsVarSOC(), SCIPgetRhsCoefSOC(), SCIPgetRhsOffsetSOC(), use SCIPisSOCNonlinear() instead
1305- removed SCIPaddToNlpiProblemSOC()
1306- renamed SCIPincludeNonlinconsUpgrade() to SCIPincludeConsUpgradeNonlinear() and removed nodereform argument
1307- removed arguments nlinvars, linvars, lincoefs, nexprtrees, exprtrees, nonlincoefs, stickingatnode from SCIPcreateConsNonlinear() and added SCIP_EXPR* argument
1308- removed arguments nlinvars, linvars, lincoefs, nexprtrees, exprtrees, nonlincoefs from SCIPcreateConsBasicNonlinear() and added SCIP_EXPR* argument
1309- removed SCIPcreateConsNonlinear2(), SCIPcreateConsBasicNonlinear2()
1310- removed SCIPsetExprtreesNonlinear(), use SCIPchgExprNonlinear() instead
1311- removed SCIPaddExprtreesNonlinear()
1312- removed SCIPgetNLinearVarsNonlinear(), SCIPgetLinearVarsNonlinear(), SCIPgetLinearCoefsNonlinear()
1313- removed SCIPgetNExprtreesNonlinear(), SCIPgetExprtreesNonlinear(), SCIPgetExprtreeCoefsNonlinear(), SCIPgetExprgraphNodeNonlinear(), use SCIPgetExprNonlinear() instead
1314- removed argument scip from SCIPgetLhsNonlinear() and SCIPgetRhsNonlinear()
1315- removed SCIPcheckCurvatureNonlinear(), SCIPgetCurvatureNonlinear(), and SCIPgetExprtreeCurvaturesNonlinear(), use SCIPhasExprCurvature() instead
1316- renamed SCIPgetViolationNonlinear() to SCIPgetAbsViolationNonlinear()
1317- added arguments var and coef to SCIPgetLinvarMayDecreaseNonlinear() and SCIPgetLinvarMayIncreaseNonlinear() and changed return type to void
1318- removed SCIPgetExprgraphNonlinear()
1319- removed SCIPcomputeHyperplaneThreePoints(), use SCIPcomputeFacetVertexPolyhedralNonlinear() instead
1321### New API functions
1323- added SCIPallocClearMemory() and SCIPallocClearBlockMemory() to allocate a chunk of (block) memory
1324 that is initialized to zeros
1325- New internal functions for changing the default values of parameters:
1326 SCIPparamsetSetDefaultLongint(), SCIPparamsetSetDefaultReal(), SCIPparamsetSetDefaultChar(),
1327 SCIPparamsetSetDefaultString() and
1328 SCIPparamSetDefaultLongint(), SCIPparamSetDefaultReal(), SCIPparamSetDefaultChar(),
1329 SCIPparamSetDefaultString()
1330- new internal function SCIPisPackingPartitioningOrbitope() to check whether an orbitope is of
1331 packing or partitioning type
1332- new internal function SCIPcomputeOrbitVar() to compute the symmetry orbit of a variable
1333- added SCIPcalcFibHash(SCIP_Real) to hash a floating-point value to an unsigned integer
1334- added SCIPcomputeArraysIntersectionPtr() to compute intersection of two sorted arrays of pointers
1335- new function SCIPinterruptLP() (intended to be called from a different thread) that interrupts ongoing lp solve
1336- added SCIPcreateConsIndicatorGeneric() and SCIPcreateConsIndicatorGenericLinCons()
1337 which copy the interface of SCIPcreateConsIndicator() and SCIPcreateConsIndicatorLinCons() and
1338 add an activeone argument to specify whether the indicator constraint should be activated on 0 or 1.
1339 SCIPcreateConsIndicator() also adds a lessthanineq flag to choose whether the linear constraint is a less-than or greater-than inequality.
1340- added SCIPmarkDoNotAggrVar() to mark that a variable should not be aggregated
1341- added SCIPdoNotAggrVar() to query whether a variable should not be aggregated
1342- added SCIPdecompGetNBorderVars() and SCIPdecompGetNBorderConss() to get number of border variables/constraints
1343- added SCIPdecompGetVarsSize() and SCIPdecompGetConssSize() to get variable/constraint size for each block of a decomposition
1344- added SCIPincludeDialogDefaultBasic()
1345- added SCIPintervalAreDisjointEps(), SCIPintervalIntersectEps()
1346- added SCIPintervalEntropy()
1347- added SCIPintervalPropagateWeightedSum()
1348- added SCIPcalcRootNewton()
1349- added SCIPvarGetImplicVarBounds()
1350- added SCIPcreateRowprep(), SCIPfreeRowprep(), SCIPcopyRowprep(),
1351 SCIProwprepGetNVars(), SCIProwprepGetVars(), SCIProwprepGetCoefs(), SCIProwprepGetSide(), SCIProwprepGetSidetype(), SCIProwprepIsLocal(), SCIProwprepGetName(), SCIProwprepGetNModifiedVars(), SCIProwprepGetModifiedVars(),
1352 SCIProwprepReset(), SCIProwprepAddSide(), SCIProwprepAddConstant(), SCIProwprepSetSidetype(), SCIProwprepSetLocal(), SCIProwprepRecordModifications(),
1353 SCIPprintRowprep(), SCIPprintRowprepSol(), SCIPensureRowprepSize(), SCIPaddRowprepTerm(), SCIPaddRowprepTerms(), SCIPgetRowprepViolation(), SCIPisRowprepViolationReliable(),
1354 SCIPmergeRowprepTerms(), SCIPcleanupRowprep(), SCIPcleanupRowprep2(), SCIPscaleupRowprep(), SCIPscaleRowprep(),
1355 SCIPgetRowprepRowConshdlr(), SCIPgetRowprepRowCons(), SCIPgetRowprepRowSepa()
1356- added SCIPsetClockEnabled()
1357- added SCIPisSolveInterrupted() to check whether SCIPinterruptSolve() has been called
1358- added SCIPgetNPresolRounds()
1359- added SCIPgetNUnfixedLPCols()
1360- moved SCIPhistoryGetInferenceSum() and SCIPhistoryGetAvgConflictlength() from internal to public API
1363- added SCIPincludeExprhdlr(), SCIPgetExprhdlrs(), SCIPgetNExprhdlrs(), SCIPfindExprhdlr()
1364- added SCIPgetExprhdlrVar(), SCIPgetExprhdlrValue(), SCIPgetExprhdlrSum(), SCIPgetExprhdlrProduct(), SCIPgetExprhdlrPower()
1365- added SCIPexprhdlrSetCopyFreeHdlr(), SCIPexprhdlrSetCopyFreeData(), SCIPexprhdlrSetPrint(), SCIPexprhdlrSetParse(), SCIPexprhdlrSetCurvature(), SCIPexprhdlrSetMonotonicity(), SCIPexprhdlrSetIntegrality(), SCIPexprhdlrSetHash(), SCIPexprhdlrSetCompare(), SCIPexprhdlrSetDiff(), SCIPexprhdlrSetIntEval(), SCIPexprhdlrSetSimplify(), SCIPexprhdlrSetReverseProp(), SCIPexprhdlrSetEstimate()
1366- added SCIPexprhdlrGetName(), SCIPexprhdlrGetDescription(), SCIPexprhdlrGetPrecedence(), SCIPexprhdlrGetData(), SCIPexprhdlrHasPrint(), SCIPexprhdlrHasBwdiff(), SCIPexprhdlrHasFwdiff(), SCIPexprhdlrHasIntEval(), SCIPexprhdlrHasEstimate(), SCIPexprhdlrHasInitEstimates(), SCIPexprhdlrHasSimplify(), SCIPexprhdlrHasCurvature(), SCIPexprhdlrHasMonotonicity(), SCIPexprhdlrHasReverseProp()
1367- added SCIPexprhdlrComp()
1368- added SCIPexprhdlrGetNIntevalCalls(), SCIPexprhdlrGetIntevalTime(), SCIPexprhdlrGetNReversepropCalls(), SCIPexprhdlrGetReversepropTime(), SCIPexprhdlrGetNCutoffs(), SCIPexprhdlrGetNDomainReductions(), SCIPexprhdlrIncrementNDomainReductions(), SCIPexprhdlrGetNEstimateCalls(), SCIPexprhdlrGetEstimateTime(), SCIPexprhdlrGetNBranchings(), SCIPexprhdlrIncrementNBranchings(), SCIPexprhdlrGetNSimplifyCalls(), SCIPexprhdlrGetSimplifyTime(), SCIPexprhdlrGetNSimplifications()
1369- added SCIPprintExpressionHandlerStatistics()
1370- added SCIPincludeExprhdlrEntropy(), SCIPcreateExprEntropy(), SCIPisExprEntropy()
1371- added SCIPincludeExprhdlrErf(), SCIPcreateExprErf(), SCIPisExprErf()
1372- added SCIPcreateExprAbs(), SCIPincludeExprhdlrAbs(), SCIPisExprAbs()
1373- added SCIPcreateExprExp(), SCIPincludeExprhdlrExp(), SCIPisExprExp()
1374- added SCIPcreateExprLog(), SCIPincludeExprhdlrLog(), SCIPisExprLog()
1375- added SCIPcreateExprPow(), SCIPcreateExprSignpower(), SCIPincludeExprhdlrPow(), SCIPincludeExprhdlrSignpower(), SCIPisExprSignpower(), SCIPgetExponentExprPow(), SCIPisExprPower()
1376- added SCIPincludeExprhdlrProduct(), SCIPcreateExprProduct(), SCIPgetCoefExprProduct(), SCIPisExprProduct()
1377- added SCIPincludeExprhdlrSum(), SCIPcreateExprSum(), SCIPsetConstantExprSum(), SCIPappendExprSumExpr(), SCIPmultiplyByConstantExprSum(), SCIPgetCoefsExprSum(), SCIPgetConstantExprSum(), SCIPisExprSum()
1378- added SCIPincludeExprhdlrSin(), SCIPcreateExprSin(), SCIPincludeExprhdlrCos(), SCIPcreateExprCos(), SCIPisExprSin(), SCIPisExprCos()
1379- added SCIPincludeExprhdlrValue(), SCIPcreateExprValue(), SCIPgetValueExprValue(), SCIPisExprValue()
1380- added SCIPincludeExprhdlrVar(), SCIPcreateExprVar(), SCIPgetVarExprVar(), SCIPisExprVar()
1381- added SCIPincludeExprhdlrVaridx(), SCIPcreateExprVaridx(), SCIPisExprVaridx(), SCIPgetIndexExprVaridx(), SCIPsetIndexExprVaridx()
1384- added SCIPcaptureExpr(), SCIPreleaseExpr(), SCIPexprGetNUses()
1385- added SCIPexprGetHdlr(), SCIPexprGetData(), SCIPexprSetData(), SCIPexprGetOwnerData()
1386- added SCIPevalExpr(), SCIPgetExprNewSoltag(), SCIPexprGetEvalValue(), SCIPexprGetEvalTag()
1387- added SCIPevalExprGradient(), SCIPevalExprHessianDir(), SCIPexprGetDerivative(), SCIPexprGetDot(), SCIPexprGetBardot(), SCIPexprGetDiffTag()
1388- added SCIPevalExprActivity(), SCIPexprGetActivity(), SCIPexprGetActivityTag(), SCIPexprSetActivity()
1389- added SCIPcomputeExprCurvature(), SCIPexprGetCurvature(), SCIPexprSetCurvature()
1390- added SCIPcomputeExprIntegrality(), SCIPexprIsIntegral(), SCIPexprSetIntegrality()
1391- added SCIPcheckExprQuadratic(), SCIPfreeExprQuadratic(), SCIPevalExprQuadratic(), SCIPprintExprQuadratic(), SCIPcomputeExprQuadraticCurvature()
1392- added SCIPexprGetQuadraticData(), SCIPexprGetQuadraticQuadTerm(), SCIPexprGetQuadraticBilinTerm(), SCIPexprAreQuadraticExprsVariables()
1393- added SCIPcreateExpr(), SCIPcreateExpr2(), SCIPcreateExprQuadratic(), SCIPcreateExprMonomial()
1394- added SCIPappendExprChild(), SCIPreplaceExprChild(), SCIPremoveExprChildren()
1395- added SCIPduplicateExpr(), SCIPduplicateExprShallow(), SCIPcopyExpr()
1396- added SCIPparseExpr()
1397- added SCIPprintExpr(), SCIPdismantleExpr()
1398- added SCIPprintExprDotInit(), SCIPprintExprDotInit2(), SCIPprintExprDot(), SCIPprintExprDotFinal(), SCIPshowExpr()
1399- added SCIPcompareExpr(), SCIPhashExpr()
1400- added SCIPsimplifyExpr(), SCIPreplaceCommonSubexpressions()
1401- added SCIPgetExprNVars(), SCIPgetExprVarExprs()
1402- added SCIPcallExprPrint(), SCIPcallExprCurvature(), SCIPcallExprMonotonicity(), SCIPcallExprEval(), SCIPcallExprEvalFwdiff(), SCIPcallExprInteval(), SCIPcallExprEstimate(), SCIPcallExprInitestimates(), SCIPcallExprSimplify(), SCIPcallExprReverseprop()
1403- added SCIPexprcurvPowerInv(), SCIPexprcurvMonomialInv()
1406- added SCIPcreateExpriter(), SCIPfreeExpriter()
1407- added SCIPexpriterIsInit(), SCIPexpriterInit()
1408- added SCIPexpriterRestartDFS(), SCIPexpriterSetStagesDFS(), SCIPexpriterGetCurrent(), SCIPexpriterGetStageDFS(), SCIPexpriterGetChildIdxDFS(), SCIPexpriterGetChildExprDFS(), SCIPexpriterGetParentDFS()
1409- added SCIPexpriterGetCurrentUserData(), SCIPexpriterGetChildUserDataDFS(), SCIPexpriterGetExprUserData(), SCIPexpriterSetCurrentUserData(), SCIPexpriterSetExprUserData(), SCIPexpriterSetChildUserData()
1410- added SCIPexpriterGetNext(), SCIPexpriterSkipDFS(), SCIPexpriterIsEnd()
1411- added SCIPexprintHessianSparsity(), SCIPexprintHessian()
1413Constraint handlers for NLP:
1414- added SCIPgetCurBoundsTagNonlinear(), SCIPgetLastBoundRelaxTagNonlinear(), SCIPincrementCurBoundsTagNonlinear()
1415- added SCIPgetVarExprHashmapNonlinear()
1416- added SCIPprocessRowprepNonlinear()
1417- added SCIPassumeConvexNonlinear()
1418- added SCIPcollectBilinTermsNonlinear(), SCIPgetBilinTermIdxNonlinear(), SCIPgetBilinTermNonlinear(), SCIPevalBilinAuxExprNonlinear(), SCIPinsertBilinearTermExistingNonlinear(), SCIPinsertBilinearTermImplicitNonlinear()
1419- added SCIPcomputeFacetVertexPolyhedralNonlinear()
1420- added SCIPgetExprNonlinear()
1421- added SCIPcheckQuadraticNonlinear(), SCIPchgLhsNonlinear(), SCIPchgRhsNonlinear(), SCIPchgExprNonlinear(), SCIPaddExprNonlinear()
1422- added SCIPgetRelViolationNonlinear()
1423- added SCIPgetExprNLocksPosNonlinear(), SCIPgetExprNLocksNegNonlinear(), SCIPgetExprAuxVarNonlinear(), SCIPgetExprNEnfosNonlinear(), SCIPgetExprEnfoDataNonlinear(), SCIPsetExprEnfoAuxValueNonlinear()
1424- added SCIPgetExprNPropUsesActivityNonlinear(), SCIPgetExprNSepaUsesActivityNonlinear(), SCIPgetExprNAuxvarUsesNonlinear(), SCIPregisterExprUsageNonlinear()
1425- added SCIPgetExprAbsOrigViolationNonlinear(), SCIPgetExprAbsAuxViolationNonlinear(), SCIPgetExprRelAuxViolationNonlinear()
1426- added SCIPgetExprBoundsNonlinear(), SCIPtightenExprIntervalNonlinear(), SCIPmarkExprPropagateNonlinear()
1427- added SCIPaddExprViolScoreNonlinear(), SCIPaddExprsViolScoreNonlinear(), SCIPgetExprViolScoreNonlinear()
1428- added SCIPgetExprPartialDiffNonlinear(), SCIPgetExprPartialDiffGradientDirNonlinear()
1429- added SCIPevalExprQuadraticAuxNonlinear()
1430- added SCIPincludeNlhdlrNonlinear(), SCIPfindNlhdlrNonlinear(), SCIPgetNNlhdlrsNonlinear(), SCIPgetNlhdlrsNonlinear(), SCIPgetNlhdlrExprDataNonlinear()
1431- added SCIPcreateConsQuadraticNonlinear() and SCIPcreateConsBasicQuadraticNonlinear() to create a nonlinear constraint that is quadratic
1432- added SCIPcreateConsBasicSignpowerNonlinear() to create a nonlinear constraint that looks like the former abspower or signpower constraints
1435- added SCIPincludeNlhdlrBilinear(), SCIPgetExprsBilinear(), SCIPgetExprsdataBilinear(), SCIPgetNExprsBilinear(), SCIPaddIneqBilinear()
1436- added SCIPincludeNlhdlrConvex(), SCIPincludeNlhdlrConcave(), SCIPhasExprCurvature()
1437- added SCIPincludeNlhdlrDefault()
1438- added SCIPincludeNlhdlrPerspective()
1439- added SCIPincludeNlhdlrQuadratic()
1440- added SCIPincludeNlhdlrQuotient()
1441- added SCIPincludeNlhdlrSoc(), SCIPisSOCNonlinear(), SCIPfreeSOCArraysNonlinear()
1442- added SCIPnlhdlrSetCopyHdlr(), SCIPnlhdlrSetFreeHdlrData(), SCIPnlhdlrSetFreeExprData(), SCIPnlhdlrSetInitExit(), SCIPnlhdlrSetProp(), SCIPnlhdlrSetSepa()
1443- added SCIPnlhdlrGetName(), SCIPnlhdlrGetDesc(), SCIPnlhdlrGetDetectPriority(), SCIPnlhdlrGetEnfoPriority(), SCIPnlhdlrIsEnabled(), SCIPnlhdlrGetData()
1444- added SCIPnlhdlrHasIntEval(), SCIPnlhdlrHasReverseProp(), SCIPnlhdlrHasInitSepa(), SCIPnlhdlrHasExitSepa(), SCIPnlhdlrHasEnfo(), SCIPnlhdlrHasEstimate()
1445- added SCIPnlhdlrComp()
1448- added SCIPgetNlpiSolverPointer(), SCIPcreateNlpiProblem(), SCIPfreeNlpiProblem(), SCIPgetNlpiProblemPointer(), SCIPaddNlpiVars(), SCIPaddNlpiConstraints(), SCIPsetNlpiObjective(), SCIPchgNlpiVarBounds(), SCIPchgNlpiConsSides(), SCIPdelNlpiVarSet(), SCIPdelNlpiConsSet(), SCIPchgNlpiLinearCoefs(), SCIPchgNlpiExpr(), SCIPchgNlpiObjConstant(), SCIPsetNlpiInitialGuess(), SCIPsolveNlpiParam(), SCIPgetNlpiSolstat(), SCIPgetNlpiTermstat(), SCIPgetNlpiSolution(), SCIPgetNlpiStatistics()
1449- added SCIPincludeNlpSolverAll()
1450- added SCIPincludeNlpSolverFilterSQP(), SCIPgetSolverNameFilterSQP(), SCIPgetSolverDescFilterSQP(), SCIPisFilterSQPAvailableFilterSQP()
1451- added SCIPincludeNlpSolverIpopt()
1452- added SCIPincludeNlpSolverWorhp()
1453- added SCIPnlpiOracleChgExpr()
1454- added SCIPcreateNlpiProblemFromNlRows()
1455- added SCIPnlpiOracleGetObjectiveConstant()
1456- added SCIPnlpiOracleIsVarNonlinear(), SCIPnlpiOracleGetVarCounts(), SCIPnlpiOracleIsConstraintNonlinear()
1457- added SCIPnlpiGetNProblems(), SCIPnlpiGetProblemTime(), SCIPnlpiGetNSolves(), SCIPnlpiGetSolveTime(), SCIPnlpiGetEvalTime(), SCIPnlpiGetNIterations(), SCIPnlpiGetNTermStat(), SCIPnlpiGetNSolStat(), SCIPnlpiMergeStatistics()
1458- added SCIPmergeNLPIStatistics(), SCIPprintNLPIStatistics()
1459- added SCIPnlpiOracleResetEvalTime(), SCIPnlpiOracleGetEvalTime()
1460- added SCIPaddNlpiProblemNlRows()
1463- added SCIPincludeCutsel(), SCIPincludeCutselBasic(), SCIPsetCutselCopy(), SCIPsetCutselFree(), SCIPsetCutselInit(), SCIPsetCutselExit(), SCIPsetCutselInitsol(), SCIPsetCutselExitsol(), SCIPfindCutsel(), SCIPgetCutsels(), SCIPgetNCutsels(), SCIPsetCutselPriority()
1464- added SCIPcutselGetName(), SCIPcutselGetData(), SCIPcutselGetDesc(), SCIPcutselGetPriority(), SCIPcutselSetData(), SCIPcutselIsInitialized(), SCIPcutselGetSetupTime(), SCIPcutselGetTime()
1466### Command line interface
1467### Interfaces to external software
1469- removed GAMS interface (originally in interfaces/gams) and reading capability of gms reader;
1470 the removed interface was a poorly maintained copy of the GAMS/SCIP interface that is available at
1471 https://github.com/coin-or/GAMSlinks
1472- integrated AMPL interface into main SCIP executable, that is, added possibility to use SCIP executable as solver in AMPL
1473 (AMPL calls solver with name of .nl file and -AMPL as arguments; SCIP will then attempt to solve the problem and write an AMPL solution file)
1474- the ZIMPL interface has been updated to support ZIMPL 3.4.1;
1475 the minimal required ZIMPL version is now 3.4.1
1477### Changed parameters
1479- Extended range of parameter "misc/usesymmetry" from [0,3] to [0,7], changed default from 3 to 5
1480- deleted parameter "constraints/orbitope/usedynamicprop"
1481- changed type of parameter "propagating/symmetry/recomputerestart" from SCIP_Bool to int with range [0,2]
1482- deleted parameter "propagating/symmetry/disableofrestart"
1483- parameter "heuristics/padm/original" is now an advanced parameter
1484- removed constraints/nonlinear/linfeasshift, constraints/nonlinear/reformulate, constraints/nonlinear/maxexpansionexponent, constraints/nonlinear/sepanlpmincont
1485- removed constraints/nonlinear/upgrade/abspower
1486- removed constraints/nonlinear/upgrade/and, use constraints/nonlinear/reformbinprodsand instead
1487- removed constraints/nonlinear/upgrade/bivariate
1488- removed constraints/nonlinear/upgrade/quadratic, use nlhdlr/quadratic/enabled instead
1489- changed default of constraints/nonlinear/maxproprounds from 1 to 10
1490- replaced constraints/nonlinear/enfocutsremovable by constraints/nonlinear/rownotremovable
1491- replaced constraints/nonlinear/cutmaxrange by separating/maxcoefratiofacrowprep
1492- removed constraints/quadratic/sepafreq, constraints/quadratic/propfreq, constraints/quadratic/proptiming, constraints/quadratic/eagerfreq, constraints/quadratic/maxprerounds, constraints/quadratic/delaysepa, constraints/quadratic/delayprop, constraints/quadratic/presoltiming
1493- removed constraints/quadratic/replacebinaryprod, use constraints/nonlinear/reformbinprodsfac instead
1494- removed constraints/quadratic/empathy4and, use constraints/nonlinear/reformbinprodsand instead
1495- removed constraints/quadratic/binreforminitial, constraints/quadratic/binreformbinaryonly, constraints/quadratic/binreformmaxcoef
1496- removed constraints/quadratic/cutmaxrange, constraints/quadratic/mincurvcollectbilinterms, constraints/quadratic/linearizeheursol, constraints/quadratic/checkcurvature, constraints/quadratic/checkfactorable, constraints/quadratic/checkquadvarlocks, constraints/quadratic/linfeasshift
1497- removed constraints/quadratic/maxdisaggrsize, constraints/quadratic/disaggrmergemethod, constraints/quadratic/maxproprounds, constraints/quadratic/maxproproundspresolve, constraints/quadratic/enfolplimit, constraints/quadratic/sepanlpmincont, constraints/quadratic/enfocutsremovable
1498- removed constraints/quadratic/gaugecuts, constraints/quadratic/interiorcomputation, constraints/quadratic/projectedcuts, constraints/quadratic/branchscoring, constraints/quadratic/usebilinineqbranch, constraints/quadratic/bilinineqmaxseparounds,
1499- removed constraints/quadratic/minscorebilinterms, use nlhdlr/bilinear/enabled instead
1500- removed constraints/quadratic/upgrade/linear, constraints/quadratic/upgrade/abspower, constraints/quadratic/upgrade/bivariate, constraints/quadratic/upgrade/bounddisjunction
1501- removed constraints/quadratic/upgrade/soc, use nlhdlr/soc/enabled instead
1502- renamed constraints/quadratic/upgrade/setppc to constraints/nonlinear/upgrade/setppc
1503- removed constraints/abspower/sepafreq, constraints/abspower/propfreq, constraints/abspower/proptiming, constraints/abspower/eagerfreq, constraints/abspower/maxprerounds, constraints/abspower/delaysepa, constraints/abspower/delayprop, constraints/abspower/presoltiming
1504- removed constraints/abspower/cutmaxrange, constraints/abspower/projectrefpoint, constraints/abspower/preferzerobranch, constraints/abspower/branchminconverror, constraints/abspower/addvarboundcons, constraints/abspower/linfeasshift, constraints/abspower/dualpresolve, constraints/abspower/sepainboundsonly, constraints/abspower/sepanlpmincont, constraints/abspower/enfocutsremovable
1505- removed constraints/bivariate/sepafreq, constraints/bivariate/propfreq, constraints/bivariate/proptiming, constraints/bivariate/eagerfreq, constraints/bivariate/maxprerounds, constraints/bivariate/delaysepa, constraints/bivariate/delayprop, constraints/bivariate/presoltiming
1506- removed constraints/bivariate/cutmaxrange, constraints/bivariate/linfeasshift, constraints/bivariate/maxproprounds, constraints/bivariate/ninitlprefpoints, constraints/bivariate/enfocutsremovable
1507- removed constraints/soc/sepafreq, constraints/soc/propfreq, constraints/soc/proptiming, constraints/soc/eagerfreq, constraints/soc/maxprerounds, constraints/soc/delaysepa, constraints/soc/delayprop, constraints/soc/presoltiming
1508- removed constraints/soc/projectpoint, constraints/soc/nauxvars, constraints/soc/glineur, constraints/soc/sparsify, constraints/soc/sparsifymaxloss, constraints/soc/sparsifynzgrowth, constraints/soc/linfeasshift, constraints/soc/nlpform, constraints/soc/sepanlpmincont, constraints/soc/enfocutsremovable, constraints/soc/disaggregate
1509- removed constraints/soc/generalsocupgrade, use nlhdlr/soc/compeigenvalues instead
1510- changed default of presolving/qpkktref/maxrounds from -1 to 0
1511- changed default of propagating/obbt/onlynonconvexvars from FALSE to TRUE
1512- changed default of heuristics/subnlp/resolvetolfactor from 0.001 to 1.0
1513- removed heuristics/subnlp/nlpoptfile, use nlpi/ipopt/optfile instead
1514- removed separating/convexproj/nlptimelimit
1515- removed separating/gauge/nlptimelimit
1516- removed heuristics/subnlp/nlptimelimit and heuristics/subnlp/nlpiterlimit
1517- removed heuristics/subnlp/resolvetolfactor and heuristics/subnlp/resolvefromscratch
1518- changed default of heuristics/subnlp/itermin to 20
1519- renamed heuristics/subnlp/iteroffset to heuristics/subnlp/nodesoffset
1520- renamed heuristics/subnlp/iterquotient to heuristics/subnlp/nodesfactor
1521- removed heuristics/subnlp/runalways, use heuristics/subnlp/nodesoffset=INT_MAX and heuristics/subnlp/successrateexp = 0.0 instead
1522- removed heuristics/subnlp/minimprove, heuristics/multistart/nlpminimpr
1523- Removed parameters for strongcg separator: separating/strongcg/..., i.e.,
1524 maxrounds, maxroundsroot, maxsepacutsroot, maxsepacuts, dynamiccuts. One can control the
1525 strongcg behavior throught the parameters of sepa_gomory.
1526- renamed separating/{minortho,minorthoroot,objparalfac,intsupportfac} to cutselection/hybrid/{minortho,minorthoroot,objparalweight,intsupportweight}
1530- It is now possible to add orbitope constraints to handle symmetries even if not all variables
1531 in a component of the symmetry group are binary. This feature can be enabled using the
1532 parameter "propagating/symmetry/onlybinorbitope".
1534- new parameter "propagating/symmetry/sstleaderrule" to select a rule for selecting the
1536- new parameter "propagating/symmetry/ssttiebreakrule" to select a tiebreak rule for selecting the
1538- new parameter "propagating/symmetry/sstleadervartype" to select the possible variable types
1539 for a leader in SST cuts
1540- new parameter "propagating/symmetry/addconflictcuts" to control whether SST cuts are added if
1541 a binary leader variable is in conflict with a variable in its orbit
1542- new parameter "propagating/symmetry/sstaddcuts" to control whether SST cuts are added
1543- new parameter "propagating/symmetry/sstmixedcomponents" to control whether SST cuts are added
1544 if a symmetry component contains variables of different types
1545- new parameter "propagating/symmetry/detectsubgroups" to search for orbitopes defined by subgroups
1546- new parameter "propagating/symmetry/addweaksbcs" to add Schreier Sims cuts for a single
1547 variable orbit in case an orbitope subgroup is detected
1548- new parameter "propagating/symmetry/addstrongsbcs" to add symretope facets for a single
1549 variable orbit on which the symmetry group acts like a symmetric group
1550- new parameter "propagating/symmetry/maxnconsssubgroup" to control up to which number of
1551 constraints subgroups are detected
1552- new parameter "propagating/symmetry/preferlessrows" to control whether orbitopes with
1553 smallest number of rows shall be computed by the subgroup detection heuristic
1554- new parameter "propagating/symmetry/usedynamicprop" to control if rows of full orbitope
1555 shall be ordered dynamically in propagation
1556- new parameter "separating/filtercutpoolrel" to control whether cutpool uses
1557 a dynamic strategy to separate only cuts with high relative efficacy
1558- if run from AMPL: display/statistics to enable printing detailed solve statistics after solve
1559- if run from AMPL: display/logfile to specify name of file to write SCIP log to (additionally to writing to stdout)
1560- constraints/nonlinear/propauxvars, constraints/nonlinear/varboundrelax, constraints/nonlinear/varboundrelaxamount, constraints/nonlinear/conssiderelaxamount
1561- constraints/nonlinear/vpmaxperturb, constraints/nonlinear/vpadjfacetthresh, constraints/nonlinear/vpdualsimplex
1562- constraints/nonlinear/bilinmaxnauxexprs, constraints/nonlinear/forbidmultaggrnlvar, constraints/nonlinear/checkvarlocks, constraints/nonlinear/violscale
1563- constraints/nonlinear/reformbinprods, constraints/nonlinear/reformbinprodsand, constraints/nonlinear/reformbinprodsfac
1564- constraints/nonlinear/tightenlpfeastol, constraints/nonlinear/propinenforce, constraints/nonlinear/weakcutthreshold, constraints/nonlinear/strongcutmaxcoef, constraints/nonlinear/strongcutefficacy, constraints/nonlinear/forcestrongcut, constraints/nonlinear/enfoauxviolfactor, constraints/nonlinear/weakcutminviolfactor
1565- constraints/nonlinear/branching/aux, constraints/nonlinear/branching/external, constraints/nonlinear/branching/highviolfactor, constraints/nonlinear/branching/highscorefactor, constraints/nonlinear/branching/violweight, constraints/nonlinear/branching/dualweight, constraints/nonlinear/branching/pscostweight, constraints/nonlinear/branching/domainweight, constraints/nonlinear/branching/vartypeweight, constraints/nonlinear/branching/scoreagg, constraints/nonlinear/branching/violsplit, constraints/nonlinear/branching/pscostreliable
1566- constraints/nonlinear/linearizeheursol
1567- nlhdlr/default/enabled
1568- nlhdlr/convex/enabled, nlhdlr/convex/detectsum, nlhdlr/convex/extendedform, nlhdlr/convex/cvxquadratic, nlhdlr/convex/cvxsignomial, nlhdlr/convex/cvxprodcomp, nlhdlr/convex/handletrivial
1569- nlhdlr/concave/enabled, nlhdlr/concave/detectsum, nlhdlr/concave/cvxquadratic, nlhdlr/concave/cvxsignomial, nlhdlr/concave/cvxprodcomp, nlhdlr/concave/handletrivial
1570- nlhdlr/bilinear/enabled, nlhdlr/bilinear/useinteval, nlhdlr/bilinear/usereverseprop, nlhdlr/bilinear/maxseparoundsroot, nlhdlr/bilinear/maxseparounds, nlhdlr/bilinear/maxsepadepth
1571- nlhdlr/perspective/enabled, nlhdlr/perspective/maxproprounds, nlhdlr/perspective/mindomreduction, nlhdlr/perspective/minviolprobing, nlhdlr/perspective/probingonlyinsepa, nlhdlr/perspective/probingfreq, nlhdlr/perspective/convexonly, nlhdlr/perspective/tightenbounds, nlhdlr/perspective/adjrefpoint
1572- nlhdlr/quadratic/enabled, nlhdlr/quadratic/useintersectioncuts, nlhdlr/quadratic/usestrengthening, nlhdlr/quadratic/useboundsasrays, nlhdlr/quadratic/ncutslimit, nlhdlr/quadratic/ncutslimitroot, nlhdlr/quadratic/maxrank, nlhdlr/quadratic/mincutviolation, nlhdlr/quadratic/minviolation, nlhdlr/quadratic/atwhichnodes, nlhdlr/quadratic/nstrengthlimit, nlhdlr/quadratic/ignorebadrayrestriction, nlhdlr/quadratic/ignorehighre
1573- nlhdlr/quotient/enabled
1574- nlhdlr/soc/enabled, nlhdlr/soc/mincutefficacy, nlhdlr/soc/compeigenvalues
1575- propagating/obbt/createlincons
1576- propagating/symmetry/onlybinarysymmetry
1577- separating/minor/priority, separating/minor/freq, separating/minor/maxbounddist, separating/minor/delay, separating/minor/expbackoff, separating/minor/maxminorsconst, separating/minor/maxminorsfac, separating/minor/mincutviol, separating/minor/maxrounds, separating/minor/maxroundsroot, separating/minor/ignorepackingconss
1578- separating/rlt/priority, separating/rlt/freq, separating/rlt/maxbounddist, separating/rlt/delay, separating/rlt/expbackoff, separating/rlt/maxncuts, separating/rlt/maxunknownterms, separating/rlt/maxusedvars, separating/rlt/maxrounds, separating/rlt/maxroundsroot, separating/rlt/onlyeqrows, separating/rlt/onlycontrows, separating/rlt/onlyoriginal, separating/rlt/useinsubscip, separating/rlt/useprojection, separating/rlt/detecthidden, separating/rlt/hiddenrlt, separating/rlt/addtopool, separating/rlt/goodscore, separating/rlt/badscore, separating/rlt/objparalweight, separating/rlt/efficacyweight, separating/rlt/dircutoffdistweight, separating/rlt/goodmaxparall, separating/rlt/maxparall
1579- separating/interminor/usestrengthening, separating/interminor/usebounds, separating/interminor/mincutviol, separating/interminor/maxrounds, separating/interminor/maxroundsroot
1580- table/cons_nonlinear/active, table/nlhdlr/active, table/exprhdlr/active, table/nlpi/active, table/nlhdlr_bilinear/active, table/nlhdlr_quadratic/active
1581- expr/log/minzerodistance, expr/pow/minzerodistance
1582- benders/default/maxslackvarcoef to specify maximal coefficient for slack variables; if exceeded, slack variables are fixed to zero
1583- nlpi/ipopt/optfile to specify name of Ipopt options file to use for every solve with Ipopt
1584- nlpi/ipopt/print_level, nlpi/ipopt/hsllib, nlpi/ipopt/pardisolib, nlpi/ipopt/linear_solver, nlpi/ipopt/linear_system_scaling, nlpi/ipopt/nlp_scaling_method, nlpi/ipopt/mu_strategy, nlpi/ipopt/hessian_approximation
1585- nlpi/ipopt/warm_start_push
1587- heuristics/subnlp/iterinit, heuristics/subnlp/ninitsolves, heuristics/subnlp/successrateexp
1588- heuristics/subnlp/expectinfeas, heuristics/subnlp/opttol, heuristics/subnlp/feastolfactor
1589- heuristics/subnlp/presolveemphasis, heuristics/subnlp/setcutoff
1590- new parameters "branching/inference/conflictprio" and "branching/inference/cutoffprio" that allow
1591 using the different score criteria in inference branching hierarchically
1592- new parameters "heuristics/alns/nodesquotmin", "heuristics/alns/maxcallssamesol" and "heuristics/alns/initduringroot"
1593 to control neighborhoods in ALNS
1594- new parameter "benders/default/benderscut/optimality/mir" to control whether mixed-integer rounding procedure is applied to Benders optimality cuts
1595- new parameter "misc/avoidmemout" to try to avoid running into memory limit
1596- cutselection/hybrid/dircutoffdistweight, cutselection/hybrid/efficacyweight, cutselection/hybrid/intsupportweight, cutselection/hybrid/objparalweight, cutselection/hybrid/priority
1597- new parameter "decomposition/disablemeasures" to disable expensive measures in SCIPcomputeDecompStats()
1598- new parameter "presolving/milp/probfilename" filename to write the problem to a file before MILP presolving starts
1602- removed quadratic terms from NLROWs
1603- removed SCIP_NLPPAR_INFINITY from SCIP_NLPPARAM enum
1604- added types SYM_OPTYPE, SYM_CONSTTYPE, SYM_RHSTYPE, SYM_EXPRDATA
1605- removed class SCIPInterval
1606- removed enum SCIP_EXPROP
1607- removed union SCIP_EXPROPDATA, added SCIP_EXPRDATA
1608- removed struct SCIP_EXPRTREE, use SCIP_EXPR instead
1609- removed structs SCIP_QUADELEM, SCIP_EXPRDATA_QUADRATIC, SCIP_EXPRDATA_MONOMIAL, SCIP_EXPRDATA_POLYNOMIAL, SCIP_EXPRDATA_USER
1610- removed structs SCIP_EXPRGRAPHNODE, SCIP_EXPRGRAPH
1611- removed type SCIP_EXPRBOUNDSTATUS
1612- removed struct SCIP_USEREXPRDATA
1613- added enum SCIP_MONOTONE
1614- added structs SCIP_EXPRHDLR, SCIP_EXPRHDLRDATA
1615- added union SCIP_EXPRITER_USERDATA
1616- added enum SCIP_EXPRITER_TYPE
1617- added structs SCIP_EXPRITERDATA, SCIP_EXPRITER
1618- added type SCIP_EXPRPRINT_WHAT, struct SCIP_EXPRPRINTDATA
1619- removed enum SCIP_BIVAR_CONVEXITY
1620- removed structs SCIP_QUADVAREVENTDATA, SCIP_QUADVARTERM, SCIP_BILINTERM
1621- added structs SCIP_CONSNONLINEAR_AUXEXPR, SCIP_CONSNONLINEAR_BILINTERM
1622- added type SCIP_NLHDLR_METHOD
1623- added structs SCIP_NLHDLR, SCIP_NLHDLRDATA, SCIP_NLHDLREXPRDATA
1624- enum SCIP_NLPPARAM has been changed to a struct that holds values of parameters for an NLP solve
1625- removed SCIP_NLPPAR_OPTFILE/optfile from SCIP_NLPPARAM
1626- added SCIP_NLPTERMSTAT_INTERRUPT to SCIP_NLPTERMSTAT enum; returned from NLP solver if SCIPinterruptSolve() has been called
1627- renamed SCIP_NLPTERMSTAT_TILIM to SCIP_NLPTERMSTAT_TIMELIMIT
1628- renamed SCIP_NLPTERMSTAT_ITLIM to SCIP_NLPTERMSTAT_ITERLIMIT
1629- renamed SCIP_NLPTERMSTAT_LOBJLIM to SCIP_NLPTERMSTAT_LOBJLIMIT
1630- renamed SCIP_NLPTERMSTAT_NUMERR to SCIP_NLPTERMSTAT_NUMERICERROR
1631- renamed SCIP_NLPTERMSTAT_EVALERR to SCIP_NLPTERMSTAT_EVALERROR
1632- renamed SCIP_NLPTERMSTAT_MEMERR to SCIP_NLPTERMSTAT_OUTOFMEMORY
1633- renamed SCIP_NLPTERMSTAT_LICERR to SCIP_NLPTERMSTAT_LICENSEERROR
1634- added evaltime to SCIP_NLPSTATISTICS
1635- added structs SCIP_CUTSEL, SCIP_CUTSELDATA
1640- interfaces/gams/∗
1641- interfaces/ampl/∗
1643- src/scip/cons_bivariate.{c,h}
1644- src/scip/pub_misc_nonlinear.h
1645- src/scip/misc_nonlinear.c
1646- src/scip/scip_nonlinear.{c,h}
1647- src/scip/sepa_strongcg.{h|c}
1652- added cons/linear/nonlinupgd.c
1653- added cons/nonlinear/addcons.c
1654- added cons/nonlinear/bilinhash.c
1655- added cons/nonlinear/check.c
1656- added cons/nonlinear/copy.c
1657- added cons/nonlinear/create_nlrow.c
1658- added cons/nonlinear/curvature.c
1659- added cons/nonlinear/glbconss.c
1660- added cons/nonlinear/hessian.c
1661- added cons/nonlinear/locks.c
1662- added cons/nonlinear/nlhdlr.c
1663- added cons/nonlinear/nlhdlr_bilinear.c
1664- added cons/nonlinear/nlhdlr_concave.c
1665- added cons/nonlinear/nlhdlr_convex.c
1666- added cons/nonlinear/nlhdlr_perspective.c
1667- added cons/nonlinear/nlhdlr_quadratic.c
1668- added cons/nonlinear/nlhdlr_quotient.c
1669- added cons/nonlinear/nlhdlr_soc.c
1670- added cons/nonlinear/parse.c
1671- added cons/nonlinear/presolve.c
1672- added cons/nonlinear/propagate.c
1673- added cons/nonlinear/readers.c
1674- added cons/nonlinear/reformbinprods.c
1675- added cons/nonlinear/repair.c
1676- added cons/nonlinear/transform.c
1677- added cons/nonlinear/vertexpolyhedral.c
1678- removed cons/nonlinear/getCoeffsAndConstantFromLinearExpr.c
1679- removed cons/soc/upgrade.c
1680- added expr/abs/estimation.c
1681- added expr/commonsubexprs.c
1682- added expr/compare.c
1684- added expr/cos/cos.c
1685- added expr/cos/estimation.c
1686- added expr/curvature.c
1687- added expr/derivative.c
1688- added expr/entropy/entropy.c
1689- added expr/entropy/estimation.c
1691- added expr/exp/estimation.c
1693- added expr/getvarexprs.c
1695- added expr/hessian.c
1696- added expr/integrality.c
1697- added expr/iterator.c
1698- added expr/log/estimation.c
1699- added expr/monotonicity.c
1701- added expr/pow/estimation.c
1702- added expr/pow/pow.c
1703- added expr/product/estimation.c
1705- added expr/simplify.c
1706- added expr/sin/estimation.c
1707- added expr/sin/sin.c
1708- added expr/sum/estimation.c
1709- added nlpi/exprinterpret.c
1710- speedup test nlpi:solveQP in nlpi/nlpi.c
1711- added test projection:transitivity in prob/obbt.c
1713- added test intervalarith:sincos in scip/intervalarith.c
1715- added sepa/rlt/cuts.c
1716- added sepa/rlt/product_detection.c
1717- added sepa/rlt/separation.c
1718- added tests test_compute_symmetry:expr{1,2,3,4} in symmetry/compute.c
1723- the separate NLPI library has been integrated into the main SCIP library;
1724 uses of NLPILIBFILE or NLPILIBSRC in Makefiles that use make/make.project
1729- replace flag PARASCIP by THREADSAFE
1730- option AMPL is now ON by default
1731- add -D_XOPEN_SOURCE=600 cflag for compilation on systems other than windows
1732- add compile options directly instead of modifying CMAKE_C_FLAGS and CMAKE_CXX_FLAGS
1736- prefix PKG_CONFIG_PATH with Ipopt's pkgconfig dir instead of postfixing
1737- replace flag PARASCIP by THREADSAFE
1738- flag AMPL is now true by default
1739- libscip has been renamed to libscipbase and libscipsolver has been renamed to libscip
1740 in order to have the same library names for makefiles and cmake. For downward
1741 compatibility libscipsolver still exists (as a link).
1746- fixed handling of multi-aggregation in cons_symresack and cons_orbisack
1747- SCIPgetLowerbound() now consistently returns infinity when status is infeasible
1748- improved the likelihood that a solution that satisfies the nonlinear constraints in the transformed (presolved) problem is also feasible for the original problem
1749- worked around a problem with derivatives of pow at 0 with non-integer exponents in CppAD
1750- fixed that setting of feasiblity and optimiality tolerance for NLP relaxation was overwritten with defaults when solving NLP
1751- fixed variance computation in t-value computation in hypothesis testing of reliability branching
1752- fixed potential overflow in cuts.c:evaluateLiftingFunctionKnapsack()
1753- do not transfer dual reductions to main SCIP in sepa_rapidlearning if strong dual reductions are forbidden
1754- fixed a bug in cons_setppc.c:removeDoubleAndSingletonsAndPerformDualpresolve() which led to wrong variable aggregations
1755- added missing redundancy check to coefficient tightening routine in cons_varbound that led to wrong variable locks
1756- added a check of numerics to avoid wrong reductions in cons_linear.c:simplifyInequalities()
1757- fixed a bug in cons_logicor.c regarding fixed variables that were not removed
1758- presol_milp.c handles variable fixings, suggested by PaPILO, more carefully to cover all cases that can appear
1759- fixed several reproducability bugs that led to different solving paths across multiple runs with one SCIP environment
1760- fixed check of limits/absgap, which was incorrectly applied to the scaled objective of the transformed problem
1765- in LP, use absolute instead of relative tolerances to check whether solutions from LP solver are primal feasible
1766- when a restart occurs, SCIP now asserts (during EXITSOLVE) that all relaxation-only variables are unlocked and
1767 only captured by the transformed problem.
1768- Avoid redundant calls to LP solver when LP is already flushed and solved
1769- In SCIPdebugMsg(), SCIPsetDebugMsg(), SCIPstatDebugMsg() strip directory from filename.
1770- Recompute activity of rows when checking LP solutions instead of trusting the value given by the LP solver
1771- The define NPARASCIP has been replaced by SCIP_THREADSAFE
1772- Parameters are not reset to their default values before activating an emphasis setting; this now allows to combine
1773 different emphasis settings.
1774- If a lazy bound is set to a value that is tighter than the current global bound, then the global bound is now tightened accordingly.
1776@page RN7 Release notes for SCIP 7
1778@section RN703 SCIP 7.0.3
1779*************************
1784### New API functions
1786- added function SCIPwithDebugSol() to determine whether SCIP was compiled with WITH_DEBUG_SOLUTION
1788- New function SCIPcreateConsBounddisjunctionRedundant() and SCIPcreateConsBasicBounddisjunctionRedundant() that allow
1789 the input to contain redundant literals.
1791### Changed API functions
1793- added __attribute__((format(printf,,,))) to variadic SCIP message printing functions;
1794 this enables warnings about mismatches between format string and variadic function arguments if using GCC.
1796### Interfaces to external software
1798- removed MATLAB interface from interfaces/matlab
1803- Compilation will now also work in a raw tarball of the scip git repository
1807- Make find_package more verbose and require packages to be found. Now enabled packages that are not found result in an error.
1812- Fixed numerical bug by creating and checking the empty solution when problem vanishes in presolving.
1813- Fixed several bugs in reoptimization.
1814- Fixed bug in cons_bounddisjunction in which a constraint leads to a cutoff.
1815- Fixed bug in reoptimization by avoiding redundant literals for bound disjunctions.
1816- Replace wrong usage of CMAKE_BINARY_DIR by PROJECT_BINARY_DIR in CMake system
1817- Fixed lpi_glop to use absl flag instead of GFlags
1818- Fixed invalid initialization of limits/softtime parameter in cons_components
1819- Fixed MIN macro not defined in some cases.
1820- Safeguard some API methods for querying solving statistics against segmentation faults after SCIPpresolve()
1821- Fixed unfreed solution in concurrent solving
1822- Make sure that logicor constraints are enforced/separated if genlogicor is true in cons_indicator.
1823 Thus, do not change constraints/logicor/sepafreq anymore, but output warning.
1824- Fixed assert that assumed infeasibility cannot occur in presol_boundshift.
1825- Fixed sign bug during creation of conflict constraints with almost zero left-hand side.
1826- Disabled call of conflict handler for conflict sets that contain relaxation-only variables.
1827- Fixed bug in cons_symresack by initializing all constraint data in constrans
1828- Avoid allowing the upgrade of linear constraints corresponding to indicators in propagation of nodes.
1829- Fixed bug in computing lex. min/max faces in dynamic orbitope propagation.
1830- Limit vbounds propagator to one sweep through all bounds per call in order to avoid an infinite loop.
1831- Fixed mismatches between formatter strings and arguments in calls to SCIP message printing functions.
1836- To avoid performance variablity during reoptimization, the active constraints are now stored in the same order as in the
1838- Added workaround for bug in MSVS 2019 when compiling CppAD source.
1839- The original order of variables is now only restored after presolve if `randomization/permutevars` is set to FALSE.
1841@section RN702 SCIP 7.0.2
1842*************************
1847- Extended check for valid variable and constraint names in PIP writer.
1848- Indicator constraints now write the name of the linear constraint in CIP format. This avoids a complicated
1849 name matching during parsing. The old format is still supported.
1850- The objective scale and offset are now taken into account when reading/writing problems in lp/mps/fzn/pip format.
1851 This often changes the behavior when writing transformed problems.
1853Performance improvements
1854------------------------
1856Examples and applications
1857-------------------------
1859- Add c++ Sudoku example
1864### Deleted and changed API methods
1866- deprecated SCIPsetParam(); use SCIPsetIntParam(), SCIPsetRealParam(), etc, instead
1868### New API functions
1870- new function SCIPcolGetVarProbindex() for accessing the probindex of a variable corresponding to a column
1871- added new sorting functions SCIPsortPtrRealRealBoolBool()
1876- Fixed a sign bug occuring for some cases in the computation of the directed cutoff distance
1877- Fixed overflow in inference information of cumulative constraint handler
1878- Fixed problem with propfreq == 0 in cons_linear.c
1879- Fixed aggregation heuristic in sepa_aggregation.c to not use local rows when that is requested nor modifiable rows
1880- Fixed problem with incompatibility of symmetry handling in Benders decomposition
1881- Fixed parsing of small number in CIP format of nonlinear constraint
1882- Fixed problem in upgrading full orbitopes to partitioning orbitopes
1883- Fixed treatment of negated variables in parsing orbitope constraints
1884- Fixed potential indexing error in prop_vbounds.c
1885- Fixed bug in writing fzn format
1886- Revert to old parameter value when parameter change is rejected in PARAMCHGD callback
1887- Fixed order of linker flags when building AMPL interface with cmake system.
1888- Fixed bug with ofsymcomptiming == 0: now symmetry is actually computed
1889- Improved separation for SOC constraint with multiaggregated variable on right-hand-side.
1890- Fixed bug in presol_boundshift: do not shift non-active variables
1891- Fixed bug in domain propagation for SOC constraints with negative coefficient for variable on right-hand-side.
1892- Fixed bug with multi-aggregated integer variables in cons_xor.
1893- Fixed bug with changed number of variables in storing relaxation solution in probing/diving.
1894- Fixed issues with scip statistics
1895- Fixed issue with multi-aggregated variables
1896- Fixed issue in with buffer memory in cons_cumulative
1898@section RN701 SCIP 7.0.1
1899*************************
1906- Fixed cmake module for Ipopt to support Ipopt 3.13
1907- Added cmake variable BLISS_LIBRARY_DIR to pass a bliss library
1908- Added warning to require minimal GCC version 4.8
1909- Renamed FindCriterion cmake findmodule to FindCRITERION
1913- Updated make/make.project for macOS
1914- Add SANITZERFLAGS (only OPT=dbg) to LDFLAGS also if SHARED=true (and rename SANITZERFLAGS to SANITIZERFLAGS)
1915- Fixed GCC version check in make/make.linux.gnu.dbg
1920- Fixed handling of constant term in quadratic objective of pip-reader
1921- Fixed incorrect value string for parameter estimation/completiontype
1922- Fixed initialization of first LP which led to wrong output about LPs not resolved correctly
1923- Fixed bug in SCIPcutpoolClear() function not clearing internal datastructures properly
1924- Fixed inability to set a value in a solution if it was within epsilon to the current value
1925- Fixed problems for linking optimized code with debug library of SCIP (and vice versa) by moving debug-only members
1926 to end of SCIP structs
1931- Variables that are marked as relaxation-only are no longer checked against debug solutions if
1932 they are captured by the transformed problem only.
1934@section RN700 SCIP 7.0.0
1935*************************
1940- Using the parameter "propagating/symmetry/recomputerestart" one can now decide to recompute symmetries after a
1941 restart or not. Previously one could just turn off symmetry computation after a restart. If orbital fixing
1942 has found a reduction before the restart occured, symmetries have to be updated to ensure correctness.
1943 To this end, the user can decide via "propagating/symmetry/disableofrestart" whether orbital fixing is disabled or
1944 whether symmetries are recomputed.
1946- extended relaxators statistics in solve statistics about information on number of cutoffs, improved bounds, etc.
1948- extends SMPS file reader for the stochastic information, the sto files, to read a lower bound for the discrete
1949 scenarios. The lower bound is used when creating the auxiliary variables for Benders' decomposition.
1951- extended Benders framework to solve NLPs and generate optimality and feasibility cuts from their solution
1952 when the subproblem is convex nonlinear.
1954- extended Benders framework to create copies of Benders decompositions that can be used in a multithreading environment
1956- additional functionality has been added to enable the transfer of Benders' decomposition cuts between different SCIP
1957 instances, e.g., when used in UG
1959- LP rows (SCIP_ROW) can now store pointer to a constraint from which the row originates
1961- Trust region, a new LNS heuristic, has been added to SCIP as both a standalone primal heuristic heur_trustregion.c
1962 and as a neighborhood inside of Adaptive Large Neighborhood Search (heur_alns.c). This heuristic is designed to improve the
1963 heuristic performance of the Benders' decomposition algorithm. It builds upon the successful trust region approaches
1964 applied to Benders' decomposition.
1966- Modularity of symmetry handling has been increased. It is now possible to use orbitopes (i.e., polyhedral symmetry
1967 handling techniques) and orbital fixing on the same instance.
1969- cut strengthening enabled within the Benders' decomposition framework. This uses a mix of the Improved Magnanti-Wong
1970 method and Kelly's method. The cut strengthening is enabled by setting the paramemter
1971 "benders/<bendersname>/cutstrengthenenabled" to TRUE. The parameters "cutstrengthenmult", "noimprovelimit" and
1972 "corepointperturb" control the behavior of the cut strengthening method. Additionally, the parameter
1973 "cutstrengthenintpoint" allows the user to specify the solution that is used to initialize the core point. The options
1974 are the first LP solution, the first integer feasible solution, a relative interior point, a solution vector of all
1975 ones and a solution vector of all zeros. Also, the core point can be reinitialized after each update to the incumbent
1978- added option to adjust weights of different scores in relpscost (hybrid) branching rule based on degeneracy information
1979 and skip strong branching for very high degeneracy rates
1981- added new SCIP_DECOMP* object to store user decompositions. The user can specify one or several decompositions by assigning variable
1982 and/or constraint labels either through the API or by reading a file in DEC format (which is one of the formats that GCG writes).
1983 This format specifies constraint labels, variable labels are inferred from that. The decomposition is transformed after presolving.
1984- statistics regarding the number of blocks, the largest and smallest blocks, the border, and the constraint graph are printed for the original decomposition,
1985 and for each decomposition after presolving.
1986- the decomposition can be used as initial decomposition for the Benders functionality of SCIP.
1987- new subsection "How to provide a problem decomposition" in the SCIP documentation
1989- GINS heuristic can make use of a user-provided decomposition labels in two ways:
1990 1. by selecting a block of variables that maximizes the potential, and randomly selecting a start variable for the neighborhood and/or
1991 2. by selecting an interval of consecutive blocks as neighborhood, until fixing rate is reached. In this case, no variable is randomly selected.
1993- extend potential parameter of GINS to allow computation based on local LP solution, as well
1995- new primal heuristic Adaptive Diving, which registers all publicly available dive sets from other diving heuristics.
1996 At each call, it selects one of the available dive sets based on the user's score type choice (heuristics/adaptivediving/scoretype).
1997 During the solution process, the heuristics learns online which divesets reach the best score, and executes them more frequently.
1998 The statistic output for Diving heuristics has been extended to incorporate the statistics of each dive set within Adaptive diving.
2000- Added new penalty alternating direction method (PADM) primal heuristic that splits the problem into several sub-SCIPs
2001 according to a user-provided decomposition. The sub-SCIPs are solved on an alternating basis until a feasible solution of
2002 the original problem is found.
2004- Symmetry handling constraints (cons_orbisack, cons_orbitope, cons_symresack) now have an additional parameter to encode
2005 whether they are model constraints, i.e., define the problem, or whether they are only present to handle symmetries.
2007- The symmetry code has been completely restructured. The presolvers presol_symbreak and presol_symmetry as well as the propagator
2008 prop_orbitalfixing have been merged into the single propagator prop_symmetry to avoid storing the same information
2009 multiple times. This propagator is now responsible for adding symmetry handling constraints as well as activating orbital
2010 fixing. Moreover, the new file symmetry.c contains general functions for symmetry computations like orbit computations.
2012- Variables can now be marked as "relaxation-only". This flag should be used to introduce new variables that are required
2013 to define a relaxation, but that are not part of any checked constraints. Essentially, these variables should only be used
2014 in the current SCIP solve and disregarded after a restart or in SCIP copies. Hence, these variables are not copied by SCIPcopy and
2015 SCIPgetVarCopy, they are currently not used in conflict constraints, and cuts involving them are not upgraded to linear constraints.
2016 Relaxation-only variables cannot appear in the objective function.
2018- The OSiL reader now supports nonlinear expressions of type "signpower".
2020- Expressions of form abs(x)^p * x in a nonlinear constraint are now sometimes recognized and handled by abspower constraints.
2022- If polyhedral symmetry handling methods are used (cons_orbisack, cons_orbitope, cons_symresack), it is now possible to
2023 recompute symmetries if a restart occured.
2025- upgrade some more quadratic constraints to second-order cone constraints, that is,
2026 handle linear binary variables as if squared in simple upgrade and
2027 do not require bounds for variables that have a zero entry in the computed eigenvectors in the non-simple upgrade
2029- new variable event when changing the variable type
2031- It is no longer necessary to provide a SCIP pointer for the subproblem in SCIPaddBendersSubproblem if custom solving
2032 methods are defined. A NULL pointer can be supplied to SCIPaddBendersSubproblem. In this case, no internal Benders'
2033 cut generation methods can be used.
2035- Using the parameter "constraints/symresack/checkmonotonicity" one can now decide to upgrade to packing/partitioning
2036 symresacks even if the underlying permutation is not monotone.
2038- New branching rule `vanillafullstrong`, mostly for scientific purpose, with the following features:
2039 1) no cutoff or domain reduction: only branching;
2040 2) idempotent (optional): leave SCIP, as much as possible, in the same state before / after the strong branching calls
2041 - basically, do not update any statistic;
2042 3) donotbranch (optional): do no perform branching. So that the brancher can be called as an oracle only
2043 (on which variable would you branch ? But do not branch please);
2044 4) scoreall (optional): keep scoring variables, even if infeasibility is detected;
2045 5) collectscores (optional): store the candidate scores from the last call, which can then be retrieved by calling SCIPgetVanillafullstrongData();
2046 6) integralcands (optional): consider integral candidates for branching,
2047 i.e., get candidates from SCIPgetPseudoBranchCands() instead of SCIPgetLPBranchCands().
2049- If a reference value (misc/referencevalue) is given, the primal-reference and reference-dual integrals are calculated automatically and printed within the SCIP statistics.
2051- Locally valid cuts / rows are now considered for dual proof analysis when `conflict/uselocalrows` is set to TRUE.
2053- Linking variables in the linking constraint handler (cons_linking.{ch}) can now be integer or continuous. The coefficients of the binary variables are therefore now stored as SCIP_Real.
2055- To save memory, it is now possible to remove all variables from the internal symmetry data structures that are
2056 not affected by any symmetry.
2058- Allow to filter first variables from orbits and transfer pseudo cost information to variables in orbit
2060- Add integration of external MILP presolve library as a SCIP presolver plugin that runs on MILP problems
2062- Parallelisation can be used when applying Benders' decomposition. There are two different forms of parallelisation
2063 available. The first is applying Benders' decomposition within a parallel branch-and-bound. This is achieved through
2064 the integration with the UG framework. The second is the use of shared memory parallelisation for solving the Benders'
2065 decomposition subproblems. A priority queue has been added to help with load balancing.
2067- The Benders' decomposition framework can handle MINLPs. If a convex relaxation of the MINLP exists, then this is
2068 solved to generate optimality and feasibility cuts. The extensions to the framework are:
2069 - New generic solving methods to solve convex NLP subproblems.
2070 - Modification to benderscut_opt and benderscut_feas to enable the generation of cuts from convex NLPs.
2071 - Addition of benderscut_feasalt to generate feasibility cuts from an alternative subproblem that minimises the
2072 violation of infeasible problems.
2073 - Better handling of subproblem solution results
2075- Adds a feasibility phase to the Benders' decomposition subproblem solving methods. The feasibility phase adds slack
2076 variables to each of the constraints to ensure feasibility of the subproblem. A large coefficient is given to these
2077 slack variables in the objective function to penalise constraint violations. The coefficients are progressively
2078 increased until all slack variables take the value 0.0.
2080- Improved convexity check for Benders' decomposition subproblems. The constraints of the subproblem are now checked for
2081 convexity in the initialisation of the Benders' decomposition algorithm. This enables the solving of convex NLPs as
2082 Benders' decomposition subproblems.
2084- Benders' decomposition can be applied using decomposition supplied in the DEC format. To apply Benders' decomposition
2085 the parameters decomposition/benderslabels and decomposition/applybenders must be set to TRUE.
2087- new event handler event_estim.c/h that approximates search tree completion and estimates tree size
2088 to trigger restarts; many approximations of search tree completion and estimation, including WBE, SSG, and tree profile method
2089- new display column that reports approx. search tree completion during the search, and an overview in the statistics table
2090- added resources (script, tutorial, test data) to adapt tree size estimation to user instances.
2092- Orbital Fixing uses a list of variables that have been fixed globally since the computation of symmetries to filter
2093 symmetries. Previously, some plugins were disabled, which is not necessary anymore.
2095- A new presolver "dualsparsify" was added. It tries to combine columns (i.e. variables) to cancel nonzero coefficients in the constraint matrix.
2097- The presolver "tworowbnd" was implemented with better performance.
2099- To be able to calculate better bounds for the dual variables, the presolver "dualinfer" was extended by the ability to perform convex combinations of continuous columns.
2101- allow disabling of pricers during solving process
2103- added emphasis setting for numerically challenging instances
2105Performance improvements
2106------------------------
2108- Extended cut presolving by removing variables that been fixed at their bounds
2110- Improved branching point selection when branching on externals branching candidates. Instead of using exactly the
2111 LP solution, a point closer to the middle of the variables domain is chosen.
2113- Matrix presolvers that do not work on incomplete matrices now skip matrix creation if unsupported constraint types are detected.
2115- consLockBenders callback implemented to add down locks on the Benders' decomposition auxiliary variables and
2116 up and down locks per subproblem for all master problem variables. This allows the use of presolving and propagation
2117 with Benders' decomposition.
2119- improved performance of orbital fixing in several ways:
2120 store permutations in transposed form to improve cache efficency;
2121 reverse order to speed up filtering of permutations;
2122 handle variables globally fixed to 1 in list;
2123 use event handler to catch global fixings;
2124 speed up orbit computations;
2125 change handling of restarts;
2126 use only permutations that can contribute to a variable's orbit;
2128- allow rapid learning at local nodes
2130- allow to recompute cut without using fractional values for sepa_cgmip
2132- restrict the number of the clique table nonzeros relative to the number of problem nonzeros, which could be a performance bottleneck.
2134- variable fixings of LP face heuristic are now computed earlier; subproblem creation is skipped if not enough variables are fixed.
2136- Improved domcol presolver to not require a complete representation of all constraints in the matrix
2138- performance improvement of adaptive large neighborhood search heuristic on merely continuous problems. The heuristic
2139 stops if presolving in the sub-SCIP fixes less than 50 % of the current target fixing rate over all variables
2140 (including continuous).
2142- reduce memory usage in symmetry detection by a staggered allocation with decreasing overhead for larger instances
2144- improved full orbitope propagation using a static implementation or a dynamic reordering of orbitope rows by a global rank function
2146- improved detection of packing/partitioning orbitopes
2148- enable an in-tree restart if after a reasonable initialization, the estimated size of the remaining tree is large.
2151Examples and applications
2152-------------------------
2154- added methods to set and get hmin and hmax for optcumulative constraints
2159### New and changed callbacks
2161- new optional callback `SCIP_DECL_DIVESETAVAILABLE` to check preconditions for this dive set, e.g., if an incumbent solution is available,
2162 which is passed as new argument to SCIPcreateDiveset(). SCIPcreateDiveset() has another new parameter "ispublic".
2164- new callback `SCIP_DECL_CONSHDLRCOPY` and `SCIP_DECL_CONSCOPY` in cons_orbisack and cons_symresack
2166- new `idempotent` argument to SCIPgetVarStrongbranchInt() and SCIPgetVarStrongbranchFrac(),
2167 so that statistics are not updated during the call. Likewise, new `updatecol` and `updatestat` arguments to SCIPcolGetStrongbranch().
2169- callback `SCIP_DECL_CONSHDLRENFOLP` can now also return SCIP_SOLVELP as *result, which indicates to the SCIP core that the LP relaxation
2170 should be solved again because the primal feasibility tolerance of the LP has been tightened (using SCIPsetLPFeastol())
2172- extension of SCIP_PQUEUE by a new callback SCIP_DECL_PQUEUEELEMCHGPOS to catch swaps as well as functionality to delete arbitrary elements from the priority queue.
2174### Deleted and changed API methods
2177 + now for all lp interfaces consistent requirements on SCIP_LPPAR:
2178 LPITLIM and BARRIERCONVTOL positive or zero; FEASTOL, DUALFEASTOL, LPTILIM strictly positive
2179 + now projecting SCIP_LPPAR values on feasible values for each lp interface
2180 + add interface to Glop
2181 + fixed mapping between scaling parameter values in Gurobi LPI lpi_grb
2183 + removed method SCIPseparateCoversOrbisack() in cons_orbisack.h since the orbitope constraint
2184 handler has its own implementation of this routine with advanced features now
2185 + renamed SCIPgetGeneratorsSymmetry() to SCIPgetSymmetry() and removed two arguments
2186 + extended method SCIPgetSymmetry(): It is possible to access both the original and
2187 transposed permutations matrix as well as the (independent symmetry) components of a permutation group now.
2188 + arguments of functions SCIPcreateConsOrbisack(), SCIPcreateConsBasicOrbisack(), SCIPcreateConsOrbitope(),
2189 SCIPcreateConsBasicOrbitope(), SCIPcreateConsSymresack(), SCIPcreateConsBasicSymresack(), and SCIPcreateSymbreakCons() extended
2190 by "ismodelcons" to encode whether the constraints are model constraints or not
2191 + the function SCIPgetSymmetry() no longer accepts the parameter recompute, but has parameter permvarmap as new input
2192 + removed SCIPgetPermvarsObjSymmetry(), SCIPsetSymmetryComponentblocked(), SCIPgetSymmetryComponentblocked(),
2193 SCIPgetSyminfoGloballyFixedVars(), SCIPcomputeGroupOrbitsSymbreak, SCIPincludePresolSymmetry(),SCIPincludePresolSymbreak(),
2194 and SCIPincludePropOrbitalfixing()
2195 + add function SCIPcomputeOrbitsComponentsSym() to compute orbits without filtering permutations and indices of orbits for each variable
2196- SCIPallowObjProp() and SCIPallowDualReds() are deprecated and replaced by SCIPallowWeakDualReds() and SCIPallowStrongDualReds(), respectively
2197- Benders' decomposition
2198 + changed SCIPstoreBenderscutCut() in scip_benders.c to SCIPstoreBendersCut(). Where this function used to take a
2199 SCIP_BENDERSCUT pointer, it now accepts a SCIP_BENDERS pointer.
2200 + the functions SCIPsolveBendersSubproblem() no longer accepts the parameter type. The type is not a necessary
2201 argument for the subproblem solving method.
2202 + arguments of functions SCIPbendersSolveSubproblemLP(), SCIPbendersSolveSubproblemCIP(), and SCIPbendersOnlyCheckConvexRelax() changed
2203 - removed SCIPbenderscutGetNAddedCuts() and SCIPbenderscutGetAddedCutData()
2206### New API functions
2208- new argument "onlyifcomplete" in SCIPmatrixCreate() to skip matrix creation right after detecting unsupported constraint types
2209 and new arguments to count statistics when doing a clean-up of inactive variables in the constraints before building the matrix
2211- new argument "threadsafe" in SCIPcopy(), SCIPcopyConsCompression(), SCIPcopyOrig(), SCIPcopyOrigConsCompression and
2212 SCIPcopyBenders(). This argument must only be set to TRUE if the source and target SCIP instances are to be solved in
2213 parallel. Setting this argument to TRUE has a performance cost.
2215- new argument "append" in SCIPsetModifiedDefaultSettingsIpopt()
2216- functions SCIPclearRelaxSolVals(), SCIPsetRelaxSolVal(), SCIPsetRelaxSolVals(), SCIPsetRelaxSolValsSol(), and SCIPmarkRelaxSolValid()
2217 receive an additional argument "relax" to store the relaxation handler as creator of the relaxation solution.
2220 - SCIProwGetOriginCons() now returns a SCIP_CONS* instead of a SCIP_CONSHDLR*, use SCIProwGetOriginConshdlr() for the previous behavior
2221 - SCIPcreateRowCons() and SCIPcreateEmptyRowCons() now expect a SCIP_CONS* instead of a SCIP_CONSHDLR*,
2222 use SCIPcreateRowConshdlr() and SCIPcreateEmptyRowConshdlr(), respectively, for the previous behavior
2223 - deprecated SCIPlpfeastol() and SCIPchgLpfeastol(), use SCIPgetLPFeastol() and SCIPsetLPFeastol()
2225- new parameter "divecontext" for every method that queries statistics for a diveset. The context can be used to distinguish between the dive set
2226 as single (standalone) heuristic or within Adaptive Diving.
2227- new parameters "divecontext" and "iterlim" to SCIPperformGenericDivingAlgorithm() to control in which context (single,adaptive) statistics are updated.
2229- SCIPcopyVars, SCIPcopy, SCIPcopyConsCompression, and SCIPgetVarCopy do not copy variables that are marked as relaxation-only,
2230 thus it cannot be assumed anymore that each active variable from the master SCIP also has a counterpart in the copy.
2231 SCIPcopy, SCIPcopyConsCompression, and SCIPcopyConss can now return *valid=TRUE if some non-checked and non-enforced constraints were not copied, e.g.,
2232 because they involved relaxation-only variables. Thus, a copy is already regarded as valid if all checked or enforced constraints were copied successfully.
2234- linking constraint handler:
2235 - changed type of vals argument from int* to SCIP_Real* in SCIPcreateConsLinking() and SCIPcreateConsBasicLinking()
2236 - SCIPgetIntvarLinking() has been renamed to SCIPgetLinkvarLinking().
2237 - changed return value of SCIPgetValsLinking() from int* to SCIP_Real*.
2238 - new method SCIPgetBinvarsDataLinking().
2240- SCIPbendersCheckSubproblemOptimality() now returns a boolean indicating whether the subproblem is optimal or not.
2241 Previously this result was returned through a parameter. The change was required to facilitate the integration with
2244- deleted SCIPcombineTwoInt(), SCIPcombineThreeInt(), SCIPcombineFourInt(); use the appropriate SCIPhashTwo(), ..., SCIPhashSeven() method instead
2246- SCIPsetupBendersSubproblem takes a parameter of the enforcement type.
2248- SCIPcreateNlpiProb takes a hashmap to store the map between the nlrows and the index in the nlrow array.
2250### New API functions
2252- SCIPallowWeakDualReds() and SCIPallowStrongDualReds() replace the deprecated SCIPallowObjProp() and SCIPallowDualReds(), respectively
2253- methods have been added to facilitate the transfer of Benders' decomposition cuts between solvers in UG. These include
2254 SCIPapplyBendersStoredCuts(), SCIPbendersGetNStoredCuts(), SCIPbendersGetStoredCutData() and
2255 SCIPbendersGetStoredCutOrigData().
2256- added SCIPisConvexAbspower()
2257- new functions SCIPsolGetType(), SCIPsolGetRelax(), SCIPsolSetRelax(), SCIPsolSetLPRelaxation(), SCIPsolSetStrongbranch(),
2258 SCIPsolSetPseudo to set or query the new type attribute of a primal solution. The type attribute gives information
2259 about the origin of the solution, ie, whether it was created by a relaxation handler,
2260 by the LP relaxation, by strong branching, by the current pseudo solution, or by a primal heuristic.
2261 The meaning of the argument 'heur' in all creation methods for primal solutions such as SCIPcreateSol() stays unchanged.
2262- added SCIProwGetOriginConshdlr(), SCIPcreateRowConshdlr(), SCIPcreateEmptyRowConshdlr()
2263- new API functions SCIPsetCommonSubscipParams(), SCIPtranslateSubSol(), and SCIPtranslateSubSols() shared by several Large Neighborhood Search heuristics.
2264- new API function SCIPgetLPDualDegeneracy() to get two measures for the dual degeneracy of the current LP
2265- new API functions SCIPdivesetIsAvailable() to check preconditions of a dive set and SCIPdivesetIsPublic() to check if the dive set can be used
2266 by other primal heuristics.
2267- new API functions SCIPcomputeOrbitsSym(), SCIPcomputeOrbitsFilterSym(), SCIPgetPropertiesPerm(), SCIPdetermineBinvarAffectedSym(),
2268 SCIPdetermineNVarsAffectedSym(), SCIPcomputeComponentsSym(), and SCIPextendSubOrbitope(), SCIPgenerateOrbitopeVarsMatrix() for symmetry computations
2269- new API functions SCIPvarIsRelaxationOnly() and SCIPvarMarkRelaxationOnly() to query and set, resp., whether a variable is marked as relaxation-only
2270- new API functions SCIPconshdlrGetNUpdateConss() and SCIPconshdlrGetUpdateConss(), for expert users only
2271- new API function SCIPgetNConflictDualproofsApplied()
2272- new API functions SCIPeventGetOldtype() and SCIPeventGetNewtype() for the new event when changing the variable type
2273- new API function SCIPisConvexConsQuadratic() to check whether a quadratic constraint is convex when a given set of variables would be fixed
2274- new API functions SCIPgetLPFeastol(), SCIPsetLPFeastol(), and SCIPresetLPFeastol() to get, set, and reset (to the default), respectively, the primal
2275 feasibility tolerance for the LP relaxation
2276- new API functions SCIPcleanupConss{Linear,Varbound,Setppc,Logicor,Knapsack}() to clean up inactive variables from those types of linear constraints
2277- new API function SCIPsetBendersSubproblemComp() used to add a custom comparison method for ordering the Benders'
2278 decomposition subproblem solves. The comparison method is used to help with load balancing.
2279- new API function SCIPgetRowObjParallelism to get the objective parallelism of a row
2280- new API function SCIPcolGetAge to get the age of a column
2281- added SCIPhashThree(), SCIPhashFive(), SCIPhashSix(), and SCIPhashSeven() that complement SCIPhashTwo(), SCIPhashFour() to combine 32bit integers to
2283- new API function SCIPgenerateAndApplyBendersOptCut is used to generate a Benders' optimality cut using the dual
2284 solutions. This function can be supplied vectors for the primal and dual solution for generating an optimality cut.
2285 This avoids the need for a SCIP instance to solve the Benders' decomposition subproblem and generating cuts.
2286- new API function SCIPconsAddCoef used for adding a coefficient to a linear-type constraint.
2287- new API functions SCIPconsNonlinearGetRhs, SCIPconsNonlinearGetLhs and SCIPconsNonlinearAddLinearCoef for getting the
2288 RHS and LHS from a nonlinear-type constraint and adding a linear coefficient to the constraint.
2289- new API function SCIPbendersSolSlackVarsActive for checking whether any slack variables from the feasibility phase are
2290 active in the subproblem solution.
2291- new API functions SCIPbendersSetSubproblemType and SCIPbendersGetSubproblemType sets and gets the subproblem type.
2293 - Convex constraints with continuous variables
2294 - Convex constraints with discrete variables
2295 - Non-convex constraints with continuous variables
2296 - Non-convex constraints with discrete variables
2297- new API functions SCIPbendersSetSubproblemIsNonlinear() and SCIPbendersSubproblemIsNonlinear() for setting and
2298 identifying whether the Benders' decomposition subproblems contain nonlinear constraints. Similarly, the functions
2299 SCIPbendersSetMasterIsNonlinear() and SCIPbendersMasterIsNonlinear() sets and identifies whether the Benders'
2300 decomposition master problem contains nonlinear constraints.
2301- new API function SCIPapplyBendersDecomposition for applying Benders' decomposition given a decomposition in the DEC
2303- new API function SCIPwasNodeLastBranchParent to query if a node has been the parent of the most recent branching in the tree
2304- new API functions SCIPtreemodelInit(), SCIPtreemodelFree(), SCIPtreemodelIsEnabled(), SCIPtreemodelSelectCandidate() related to the new
2305 treemodel way of comparing branching candidates. These functions are only currently used for reliability pscost branching, but they can be used
2306 in other parts of the code.
2307- New function SCIPcalcChildEstimateIncrease() to compute the increase in the child estimation
2308- new API functions SCIPisOrbitalfixingEnabled() and SCIPgetSymmetryNGenerators() to check whether orbital fixing is
2309 enabled and to get the number of generators of the current symmetry group, respectively
2310- new API function SCIPdelNlRow() to remove a row from the NLP
2314- new event type SCIP_EVENTTYPE_NODEDELETE to react on nodes that are about to be deleted from the tree
2316### Changed parameters
2318- renamed parameter "propagating/orbitalfixing/enableafterrestart" to ".../symmetry/recomputerestart"
2319- Parameter "misc/allowdualreds" is now called "misc/allowstrongdualreds"
2320- Parameter "misc/allowobjprop" is now called "misc/allowweakdualreds"
2321- changed default values of propagation (new value: 1, old value: 5) and separation frequency (new value: -1, old value: 5) in cons_orbitope.c
2322- all primal heuristics that use sub-SCIPs are disabled within the heuristics fast emphasis setting
2323- deleted parameter heuristics/localbranching/useuct, use heuristics/useuctsubscip instead
2324- changed default value of "presolving/symbreak/detectorbitopes" (new value: TRUE, old value: FALSE)
2325- extended range of "misc/usesymmetry" (new range: [0,3], old range: [0,2])
2326- deleted parameter "constraints/orbisack/checkalwaysfeas"
2327- deleted parameter "constraints/orbitope/checkalwaysfeas"
2328- deleted parameter "constraints/symresack/checkalwaysfeas"
2329- deleted parameter "presolving/symmetry/maxgenerators"
2330- deleted parameter "presolving/symmetry/checksymmetries"
2331- deleted parameter "presolving/symmetry/displaynorbitvars"
2332- deleted parameter "presolving/symbreak/conssaddlp"
2333- deleted parameter "presolving/symbreak/addsymresacks"
2334- deleted parameter "presolving/symbreak/computeorbits"
2335- deleted parameter "presolving/symbreak/detectorbitopes"
2336- deleted parameter "presolving/symbreak/addconsstiming"
2337- deleted parameter "propagating/orbitalfixing/symcomptiming"
2338- deleted parameter "propagating/orbitalfixing/performpresolving"
2339- deleted parameter "propagating/orbitalfixing/recomputerestart"
2340- changed default value of "heuristics/coefdiving/freq" (old: 10, new: -1)
2341- changed default value of "heuristics/conflictdiving/freq" (old: -1, new: 10)
2342- changed default value of "heuristics/conflictdiving/lockweight" (old: 1.0, new: 0.75)
2343- replaced parameter "numerics/lpfeastol" by "numerics/lpfeastolfactor" to specify which factor should be applied to the SCIP feasibility
2344 tolerance to initialize the primal feasibility tolerance of the LP solver
2345- enabling aggressive presolving now activates all available presolving plugins,
2346 and decreases the presolving/restartfac parameter correctly with respect to default.
2347- changed default value of heuristics/rins/nodesquot to 0.3 (was 0.1), to compensate
2348 the removal of a hard coded factor of 3.0 in the code without affecting the default behavior
2349 of the RINS heuristic.
2350- changed default value of "constraints/quadratic/empathy4and" (old: 0, new: 2)
2351- changed default value of "propagating/redcost/useimplics" (old: TRUE, new: FALSE)
2355- the possibility to define the Benders' decomposition auxiliary variables as implicit integer is provided. This
2356 behavior is controlled with an additional parameter in the Benders' decomposition framework.
2357- added parameter benders/<bendersname>/cutcheck to enable the generation of Benders' decomposition cuts during solution
2359- constraints/orbitope/usedynamicprop: the possibility to propagate orbitope constraints by reordering the rows based on the
2360 branching strategy is provided (only possible for non-model constraints)
2362- new parameters heuristics/shiftandpropagate/minfixingratelp and heuristics/locks/minfixingratelp to stop the
2363 heuristics after propagating integer fixings if no sufficient fixing of the all variables (including continuous)
2364 could be achieved. These parameters help to avoid solving LP's that are comparable in hardness to the main root LP.
2366- Added parameters branching/midpull and branching/midpullreldomtrig to control by how much to move
2367 the branching point for an external branching candidate closer to the middle of the candidates domain. The
2368 default of 0.75 and 0.5, respectively, uses a point that is 75*alpha% closer to the middle of the domain, where
2369 alpha is the relative width of the candidates domain (width of local domain divided by width of global domain),
2370 if the latter is below 0.5, and alpha=1.0 otherwise. That is, with the default settings, a branching point is
2371 chosen closer to the middle of the candidates domain if the variables local domain is still similar to its
2372 global domain, but is chosen closer to the LP solution if the local domain is much smaller than the global
2375- Added parameter lp/minmarkowitz to set the Markowitz stability threshold (range 0.0001 to 0.9999).
2376 High values sacrifice performance for stability.
2378- Added parameters benders/<bendersname>/lnsmaxcalls and benders/<bendersname>/lnsmaxcallsroot to the Benders'
2379 decomposition core. These parameters limit the number of Benders' decomposition subproblem checks, for the full
2380 branch-and-bound tree and root node respective, when solving the auxiliary problem of LNS hueristics. These
2381 parameters only have effect if the lnscheck parameter is set to TRUE.
2383- Added parameter cons/linear/maxmultaggrquot to limit the maximum coefficient dynamism of an equation on which
2384 multiaggregation is performed. This replaces a compiler define of the same name.
2385 Default value is 1000, smaller values make multiaggregations numerically more stable.
2386- new global parameter heuristics/useuctsubscip that affects all LNS heuristics using common sub-SCIP parameters
2388- new parameter branching/relpscost/degeneracyaware to switch degeneracy-aware hybrid branching
2390- new parameter separation/rapidlearning/checkexec to check whether rapid learning is allowed to run locally
2391- new parameters separation/rapidlearning/check{degeneracy,dualbound,leaves,nsols,obj} to enable checking the respective feature for local rapid learning
2392- new parameter separation/rapidlearning/maxcalls to limit the number of rapid learning executions
2393- new parameter separation/rapidlearning/nwaitingnodes to set the number of waiting nodes before the dual bound is checked
2394- new parameter separation/rapidlearning/mindegeneracy to set the minimal threshold of degenerate basic-variables
2395- new parameters separation/rapidlearning/minvarconsratio to set the minimal ratio of unfixed variables in relation to basis size
2397- new parameters to control the Benders' decomposition two-phase method.
2398 - constraints/benderslp/depthfreq: after the maxdepth is reached, then the two-phase method will only be called at
2399 nodes at a depth divisible by depthfreq.
2400 - constraints/benderslp/stalllimit: after the maxdepth is reached, if there has been no improvement in the dual bound
2401 for stalllimit number of nodes, then the two-phase method is executed for the next fractional LP solution that is
2403 - constraints/benderslp/iterlimit: after the root node, only iterlimit fractional LP solutions are used at each node
2404 to generate Benders' decomposition cuts.
2406- new parameters for symmetry handling
2407 - new parameter "propagating/symmetry/maxgenerators"
2408 - new parameter "propagating/symmetry/checksymmetries"
2409 - new parameter "propagating/symmetry/displaynorbitvars"
2410 - new parameter "propagating/symmetry/conssaddlp"
2411 - new parameter "propagating/symmetry/addsymresacks"
2412 - new parameter "propagating/symmetry/detectorbitopes"
2413 - new parameter "propagating/symmetry/addconsstiming"
2414 - new parameter "propagating/symmetry/ofsymcomptiming"
2415 - new parameter "propagating/symmetry/performpresolving"
2416 - new parameter "propagating/symmetry/recomputerestart"
2417 - new parameter "constraints/symresack/checkmonotonicity"
2418 - new parameter "propagating/symmetry/compresssymmetries"
2419 - new parameter "propagating/symmetry/compressthreshold"
2420 - new parameter "propagating/symmetry/disableofrestart"
2421 - new parameter "propagating/symmetry/symfixnonbinaryvars"
2423- new parameter for enabling shared memory parallelisation for solving Benders' decomposition subproblems. The parameter
2424 benders/<bendersname>/numthreads sets the number of threads used for parallel subproblem solving.
2426- new parameters to control enhancements for solving MINLPs by Benders' decomposition
2427 - benders/<bendersname>/execfeasphase: enables the feasibility phase for solving the Benders' decomposition
2429 - benders/<bendersname>/slackvarcoef: the initial coefficient of the slack variable for the feasibility phase
2430 - benders/<bendersname>/checkconsconvexity: should the constraints be checked for convexity. This can be set to FALSE
2431 if you are certain that the NLP subproblem is convex.
2433- new parameter presolving/clqtablefac (default value 2.0) as limit on number of entries in clique table relative to number of problem nonzeros
2435- new parameter conflict/uselocalrows (default: TRUE) to incorporate locally valid cuts / rows for dual proof analysis
2437- new return code SCIP_NOTIMPLEMENTED for functions, e.g., in the LPI that have not been implemented (yet)
2439- new parameter separating/cgmip/genprimalsols that allows to generate initial primal solutions from Gomory cuts
2441- new parameter branching/relpscost/filtercandssym to allow filtering from orbits
2443- new parameter branching/relpscost/transsympscost to transfer pseudo cost information to orbit
2445- new parameters for tree size estimation and restarts:
2446 - estimation/restarts/restartpolicy (default value n)
2447 - estimation/method (default value c)
2448 - estimation/restarts/restartlimit (default value 1)
2449 - estimation/restarts/minnodes (default value 1000)
2450 - estimation/restarts/countonlyleaves (default value FALSE)
2451 - estimation/restarts/restartfactor (default value 2)
2452 - estimation/coefmonoprog (default value 0.3667)
2453 - estimation/coefmonossg (default value 0.6333)
2454 - estimation/restarts/hitcounterlim (default value 50)
2455 - estimation/reportfreq (default value -1)
2456 - estimation/regforestfilename (default value "-")
2457 - estimation/completiontype (default value a)
2458 - estimation/treeprofile/enabled (default value FALSE)
2459 - estimation/treeprofile/minnodesperdepth (default value 20)
2460 - estimation/useleafts (default value TRUE)
2461 - estimation/ssg/nmaxsubtrees (default value -1)
2462 - estimation/ssg/nminnodeslastsplit (default value 0)
2464- new parameter constraints/linear/extractcliques to turn clique extraction off
2466- new emphasis setting emphasis/numerics to increase numerical stability of (mostly) presolving operations such as (multi-)aggregations at the cost of performance.
2468- new parameters for treemodel:
2469 - new parameter branching/treemodel/enable to enable the treemodel in reliability pscost branching and possible
2470 future parts of the code where it could be used.
2471 - new parameter branching/treemodel/highrule to specify which branching rule to use when treemodel thinks the node
2472 is high in the tree.
2473 - new parameter branching/treemodel/lowrule to specify which branching rule to use when treemodel thinks the node
2475 - new parameter branching/treemodel/height to specify at which (estimated) height a node is high or low in the tree.
2476 - new parameter branching/treemodel/filterhigh to specify whether to filter dominated candidates in nodes which are
2478 - new parameter branching/treemodel/filterlow to specify whether to filter dominated candidates in nodes which are
2480 - new parameter branching/treemodel/maxfpiter to specify the maximum number of fixed-point iterations to use when
2481 computing the ratio of a variable using the fixed-point method.
2482 - new parameter branching/treemodel/maxsvtsheight to specify the maximum height to compute the SVTS score exactly
2483 before approximating it using the ratio.
2484 - new parameter branching/treemodel/fallbackinf defines the fallback strategy to use when the tree size estimates
2485 obtained by SVTS are infinite.
2486 - new parameter branching/treemodel/fallbacknoprim defines the fallback strategy to use when no primal bound is known
2487 and thus SVTS would not be able to compute a tree size (it would be infinite).
2488 - new parameter branching/treemodel/smallpscost defines the value under which pscosts are considered too small to be
2489 the deciding factor for branching, in which case it may be better not to use the treemodel.
2491- new parameters for symmetry handling constraint handlers to enforce that also non-model constraint are copied:
2492 - new parameter "constraints/orbisack/forceconscopy"
2493 - new parameter "constraints/orbitope/forceconscopy"
2494 - new parameter "constraints/symresack/forceconscopy"
2499- small changes in constants of hash functions
2500- added fast 2-universal hash functions for two to seven 32bit elements with 32bit output
2501- extended SCIPpqueueCreate() by additional callback argument SCIP_DECL_PQUEUEELEMCHGPOS to catch position changes
2502- new methods SCIPpqueueDelPos() to delete elements at a specific position in the priority queue and SCIPpqueueFind() to
2503 find a specific position. It is recommended to track position changes using the new callback SCIP_DECL_PQUEUEELEMCHGPOS.
2504 In contrast, using SCIPpqueueFind() can be slow because it needs to compare the element it searches for
2505 with each slot in the queue.
2509- The default value for DFLAGS in the non-cmake buildsystem has changed from -MM to -MMD. This will break the
2510 generation of depend.* files if that was done by a compiler call that relied on -MM. The new preferred way
2511 to handle compilation dependencies is to additionally use $(DFLAGS) when compiling the object files (.o) and
2512 to include the generated .d files in the Makefile, see also "Build system / Makefile" below.
2516 - new unit test for treemodel.
2521 - fixed an issue that may have lead to wrong status reports in the evaluation scripts
2528- avoid problem with doubly defined object together with CPLEX
2532- Removed static object compilation dependency files (depend.*). If using a GCC compatible compiler, then dependency
2533 files are now dynamically created and updated during build. The new dependency files (*.d) reside next to each object
2534 file (.o) in the corresponding obj subdirectory.
2535- added support for building against Ipopt >= 3.13
2536- unify compiler switches for Intel compiler and avoid problem with doubly defined object together with CPLEX
2541- fix and improve memory handling in symmetry computation
2542- fix shown number of applied conflicts in solving statistics
2543- fix wrongly skipping strong branching call and using old information if LP was solved with 0 iterations
2544- fix minor bug in cut score calculation
2545- fixed several bugs related to rounding locks of variables not being updated correctly
2546- small fix in cons_varbound.c to skip changing bounds of multi-aggregated variables in separation callback
2547- fixed issue in SCIPtightenVar* and SCIPinferVar* that occurs for small bound changes
2548- fixed rejecting minimal boundchange that changed sign of variable, even though SCIPisLb/UbBetter approved it
2549- fixed issue in generateCutNonConvex() which is triggered when adding quadratic constraints during the solving process
2550- fixed bug in freeing the reoptimization data if no problem exists
2551- fixed bug in SCIPreoptReleaseData() when freeing all stored constraints
2552- fixed bug when freeing the transformed problem via interactive shell if reoptimization is enabled
2553- fixed two issues related to (near-)redundant logicor constraints in presolving
2554- fixed counting of aggregations in XOR constraint handler
2555- fixed handling of unbounded solutions
2556- fixed update of LP size information when an LP error occured during probing
2557- handle special case of variable bound constraints during aggregating variables
2558- tighten sides of linear constraints before trying to upgrade them to more specialized constraints (knapsack, logic-or etc.) when calling SCIPupgradeConsLinear()
2559- fixed an issue in repair heuristic in the case of loose (noncolumn) variables
2560- allow user to correctly set heuristics/alns/(un)fixtol
2561- fixed an issue in heur_completesol which is triggered during bound widening of unbounded continuous variables
2562- fixed bug in cons_indicator if addopposite is true
2563- fixed bug in sepa_disjunctive: treat case that conflictgraph is empty
2564- added safety check in conversion to rational number to avoid overflow
2565- fixed bug in interval evaluation with power-operator in certain situations
2566- fixed behavior of SCIPmatrixCreate() regarding memory management and column generation
2567- SCIPmatrixCreate() returns complete=FALSE when locks do not add up
2568- fixed bug in sepa_oddcylce when variables are fixed
2569- fixed numerical issues related to tighter constraint sides in varbound constraint handler
2570- fixed update of watchedvars in logicor constraint handler in case of a restart during the tree
2571- fixed treatment of multi-aggregated variables in logicor constraint handler
2572- handle special case of redundant implications
2573- fixed numerical issue related to almost-0-values in pseudosolution conflict analysis
2574- fixed numerical issue related to very large greatest common dividers in linear constraint handler
2575- avoid using implications on multiaggregated variables when propagating implications
2576- fixed creation of (Lagrangian) variable bounds in the OBBT propagator
2577- fixed sorting of primal solutions
2578- fixed cleaning of clean buffer in conflict analysis
2579- avoid probing on variables with huge bounds in shift and propagate heuristic
2580- fix issue in printing solutions for variables that have been added by the dual sparsify presolver
2581- fix issue related to fixing redundant logic-or constraints after presolving
2582- fixed bug when parsing logic-or and and-constraints
2583- fixed wrong assert in updateLazyBounds()
2584- fixed bug in pricestore, which resulted in too many problem variables being added
2585- fixed bug in cons_knapsack where weight of clique was not reset after an infeasibility was detected
2586- fixed bug in presol_inttobinary which did not take into account that the aggregation could be rejected due to numerics
2587- fixed bug in debug solution mechanism in connection to variables created by presol_inttobinary
2588- fixed wrong indexing while undoing the implications from a redundant variable in SCIPshrinkDisjunctiveVarSet
2589- redundancy checks in SCIPnodeAddBoundinfer now take a possible change to an active variable into account
2590- fixed adding already added quadratic rows to NLP relaxation during solve
2591- fixed issue related to variable locks in the varbound constraint handler
2592- fixed bug in the quadratic constraint handler when changing infinite constraint sides
2593- fixed sorting of variables in linear constraint handler
2594- added additional checks to ensure numerical stability of dual proofs
2595- fixed a case when activities of a linear constraint got unreliable but where still used for reductions
2596- ensure that lhs <= rhs for linear constraints (without tolerances)
2597- make handling of read errors in SCIPfread() consistent between version with and without ZLIB
2598- correctly drop variable events in cons_indicator in restart
2599- fixed bug in cons_orbitope with upgrading of orbitope constraints
2600- additional checks in some presolvers for time limit being exceeded
2601- fixed bug in presolving of cons_varbound with multi-aggregated variables
2602- improve numerics in conflict analysis by using double-double arithmetic
2603- fixed bound acceptance condition to avoid inconsistencies
2604- fixed numerics in pseudoobj propagator by using double-double arithmetic
2609- modified display column for memory usage ("mem"), which reports the memory usage most of the time, but shows the creator name
2610 (heuristic, relaxation handler, LP relaxation, strong branching, pseudo solution) of every new incumbent solution. Together with this change,
2611 heuristic display characters have been unified to represent the type of the heuristic
2612 (diving, Large neighborhood search, propagation, etc.), see also type_heur.h.
2613- added assert that ensures that the locks of a variable have been decreased to 0 when it is freed
2614- added more output for completing a partial solution
2615- checks in debug mode that clean buffer memory is really clean when being freed are now disabled by default
2616- don't compute symmetries if reoptimization is enabled
2617- prefer integral values when fixing an almost-fixed continuous variable in the trivial presolver
2618- changed the name of the variable that is added by the OSiL reader to represent the quadratic or nonlinear parts of the objective function
2619- SCIP_EXPORT is now defined as __attribute__((__visibility__("default"))) if GCC and no SCIP config header is used
2621@page RN6 Release notes for SCIP 6
2623@section RN602 SCIP 6.0.2
2624*************************
2629- The abspower constraint handler now passes more accurate convexity
2630 information to the NLP relaxation.
2632Examples and applications
2633-------------------------
2635- added parsing functionality for optcumulative constraints in CIP format
2640### Interfaces to external software
2642- Updated the Mosek LP solver interface to support Mosek 9.0.
2649- new target to 'doc' to build documentation
2650- ctests now fail if parameter file not found
2651- add flag STATIC_GMP and improve GMP find module
2652- remove non-API methods from library (API methods use new macro SCIP_EXPORT)
2653- increase minimal required CMake version to 3.3
2654- correct paths and dependency information when installing SCIP
2658- fixed SCIP-Jack presolving bug that could lead to wrong results for Steiner arborescence problems
2659- fixed wrong unboundedness result in case not all constraints were already in the LP and enforcement was
2660 skipped because an optimal solution was found
2661- fixed wrong enforcement of constraints in the disjunction constraint handler
2662- fixed wrong behavior of concurrent solve ignoring initial solutions
2663- fixed bug in concurrent solve when problem was already solved in presolving
2664- aggregate non-artificial integer variable for XOR constraints with two binary variables and delete constraint
2665- copy the objective offset when copying the original problem
2666- fixed bug in SCIPlpiGetBInvARow in lpi_cpx using wrong size of resulting vector
2667- fixed quadratic runtime behavior in sepa_aggregation
2668- fixed statistics of separators
2669- improve numerical stability in varbound constraint handler by using double-double arithmetic
2670- fixed bug in propagation of dual proofs
2671- fixed bugs that arise for multiaggregated indicator variables by disallowing multiaggregation for them
2672- improve numerical stability in SCIPcomputeBilinEnvelope* by using double-double arithmetic
2673- fixed bug related to releasing pending bound changes in tree.c
2674- set STD FENV_ACCESS pragma to on in code that changes floating-point rounding mode
2675- disable GCC optimizations in main interval arithmetic code to prevent wrong optimizations
2676- fixed wrong assert in cons_xor concerning the variable type
2677- fixed different behavior of SCIPisLbBetter and SCIPisUbBetter between having NDEBUG defined or not
2678- correctly handle bound disjunctions in symmetry detection
2679- fixed issue in reliability branching related to the LP error flag not being reset
2680- fixed treatment of near-infinite bounds in shiftandpropagate's problem transformation
2681- fixed handling of infinite values in SCIPcomputeHyperplaneThreePoints()
2682- fixed comparisons of infinite values in heur_intshifting.c and heur_shifting.c
2683- fixed bug related to updating unprocessed cuts in the cutpool
2684- fixed bug related to enabling quadratic constraints during `CONSINITLP`
2685- add missing SCIP_EXPORT for functions used by GCG
2686- fixed memory leak and wrong initialization for trival cases in cons_symresack.c
2687- fixed bug with upgrading to packing/partitioning orbitopes
2688- fixed bug with the status while upgrading in presol_symbreak.c
2689- fixed wrong stage while clearing the conflict store
2690- fixed behavior of SCIPfixVar() by setting infeasible pointer to TRUE if fixval lies outside variable domain
2691- allow tightenVar() in SCIP_STAGE_PROBLEM stage
2692- fixed bug in cumulative constraint handler when separating the LP solution
2693- fixed issues with integer overflow in cumulative constraint handler
2694- fixed bug where the convexity of Benders' decomposition subproblems was checked even when users defined subproblem
2695 solving methods. Now, as per the documentation, the user must explicitly state whether the subproblem is convex
2696- fixed wrong indexing in heur_dualval
2697- fixed issue with basis status in SoPlex LPi
2702- statistics now output primal/dual bounds if objective limit is reached
2703- memory check in debug mode is now disabled by default
2704- message is now provided to the user to inform that automatic Benders' auxiliary variable lower bound computations are
2705 not activated when user defined subproblem solving methods are present
2706- corrected documentation of the primalgap in SCIP; describe when it will be infinite
2708@section RN601 SCIP 6.0.1
2709*************************
2714- when using a debug solution every (multi-)aggregation will be checked w.r.t. this solution
2716Performance improvements
2717------------------------
2719- try greedy solution first before solving knapsack exactly using dynamic programming in SCIPsolveKnapsackExactly,
2720 compute greedy solution by weighted median selection.
2721- don't consider implied redcost by default in the reduced cost propagator
2726### Deleted and changed API methods and macros
2728- The preprocessor macro NO_CONFIG_HEADER now needs to be defined when
2729 including SCIP header files from a SCIP build or installation that
2730 has been build via the Makefile-only build system.
2732- The following preprocessor macros have been renamed:
2733 WITH_ZLIB to SCIP_WITH_ZLIB, WITH_GMP to SCIP_WITH_GMP, WITH_READLINE
2734 to SCIP_WITH_READLINE, NO_SIGACTION to SCIP_NO_SIGACTION, NO_STRTOK_R
2735 to SCIP_NO_STRTOK_R, ROUNDING_FE to SCIP_ROUNDING_FE, ROUNDING_FP to
2736 SCIP_ROUNDING_FP, ROUNDING_MS to SCIP_ROUNDING_MS. Note, however, that
2737 the names of macros NO_RAND_R and NO_STRERROR_R have not been changed
2740### New API functions
2742- SCIPhashmapInsertInt(), SCIPhashmapSetImageInt(), and SCIPhashmapGetImageInt() to use integer values as images in hashmaps
2744### Command line interface
2746- warn about coefficients in MPS files with absolute value larger than SCIP's value for infinity
2748### Changed parameters
2750- default clock type for timing is now wallclock
2755- added unit tests for exact knapsack solving and (weighted) median selection algorithms
2762- add missing GMP dependency when compiling with SYM=bliss
2763- add DL library when linking to CPLEX to avoid linker errors
2764- new config.h header defining the current build configuration, e.g. SCIP_WITH_GMP
2769- fixed handling of weights in cons_sos1 and cons_sos2 (NULL pointer to weights)
2770- fixed handling of unbounded LPs in SCIP and in several LPIs; added heuristic method to guess solution
2771- the STO reader is capable of handling scenarios defined using lower case "rhs"
2772- fixed OPB reader for instances without explicit plus signs
2773- correct dual solution values for bound constraints
2774- fixed recognition of variable with only one lock in cons_bivariate, cons_quadratic, and cons_nonlinear
2775- fixed update of constraint violations in solution repair in cons_bivariate, cons_quadratic, and cons_nonlinear
2776- print error message and terminate if matrix entries of a column are not consecutive in mps format
2777- fixed incorrect handling of fixed variables when transfer of cuts from LNS heuristic for Benders' decomposition
2778- fix returning local infeasible status by Ipopt interface if Ipopt finds problem locally infeasible
2779- skip attempt to apply fixings in linear constraint handler during solving stage as LP rows cannot change anymore
2780- fixed bug when reading >= indicator constraints in MPS format
2781- fix issue with nodes without domain changes if we ran into solution limit in prop_orbitalfixing
2782- fixed unresolved reference to CppAD's microsoft_timer() function on builds with MS/Intel compilers on Windows
2783- ignore implications added through SCIPaddVarImplication() that are redundant to global bounds also in the
2784 special case of an implication between two binary variables; also, use implications instead of cliques in the case
2785 of a binary implied variable with nonbinary active representative
2786- fixed bug with aggregated variables that are aggregated in propagation of cons_sos1
2787- fixed some special cases in SCIPselect/SCIPselectWeighted methods
2788- relaxed too strict assertion in Zirounding heuristic
2789- fixed the upgrade routine to XOR constraints: aggregate integer variable if its coefficient has the wrong sign
2790- fixed handling of nonartificial parity variables when deleting redundant XOR constraints
2791- earlier deletion of trivial XOR constraints (at most 1 operator left)
2792- fixed wrong hashmap accesses and added sanity check for the correct hashmap type
2793- avoid copying of unbounded solutions from sub-SCIPs as those cannot be checked completely
2794- corrected the output of the first LP value in case of branch-and-price
2795- fixed possible integer overflow, which led to wrong conclusion of infeasibility, in energetic reasoning of cons_cumulative.c
2800- do not scale linear constraints to integral coefficients
2802@section RN600 SCIP 6.0.0
2803*************************
2808- new diving heuristic farkasdiving that dives into the direction of the pseudosolution and tries to construct Farkas-proofs
2809- new diving heuristic conflictdiving that considers locks from conflict constraints
2810- restructuring of timing of symmetry computation that allows to add symmetry handling components within presolving
2811- `lp/checkstability` is properly implemented for SoPlex LPI (spx2)
2812- new branching rule lookahead that evaluates potential child and grandchild nodes to determine a branching decision
2813- limits on the number of presolving rounds a presolver (maxrounds) or propagator/constraint handler (maxprerounds)
2814 participates in are now compared to the number of calls of the particular presolving method, not the number of
2815 presolving rounds in general, anymore
2816- new miscellaneous methods for constraints that have a one-row linear representation in pub_misc_linear.h
2817- a Benders' decomposition framework has been added. This framework provides the functionality for a user to solve a
2818 decomposed problem using Benders' decomposition. The framework includes classical optimality and feasibility cuts,
2819 integer optimality cuts and no-good cuts.
2820- add statistic that presents the number of resolves for instable LPs
2821- new readers for stochastic programming problems in SMPS format (reader_sto.h, reader_smps.h)
2823Performance improvements
2824------------------------
2826- cuts generated from certain quadratic constraints with convex feasible region are now global
2827- performance improvements for Adaptive Large Neighborhood Search heur_alns.c
2828 + all neighborhoods now start conservatively from maximum fixing rate
2829 + new default parameter settings for bandit selection parameters
2830 + no adjustment of minimum improvement by default
2831- improved bound tightening for some quadratic equations
2832- constraint handler checking order for original solutions has been modified to check those with negative check priority
2833 that don't need constraints after all other constraint handlers and constraints have been checked
2834- deactivate gauge cuts
2836Examples and applications
2837-------------------------
2839- new example `brachistochrone` in CallableLibrary examples collection; this example implements a discretized model to
2840 obtain the trajectory associated with the shortest time to go from point A to B for a particle under gravity only
2841- new example `circlepacking` in CallableLibrary examples collection; this example models two problems about packing
2842 circles of given radii into a rectangle
2843- new price-and-branch application for the ringpacking problem
2844- new stochastic capacitated facility location example demonstrating the use of the Benders' decomposition framework
2849### New and changed callbacks
2851- added parameter locktype to `SCIP_DECL_CONSLOCK` callback to indicate the type of variable locks
2853### Deleted and changed API methods
2856 + removed function SCIPgetTimingSymmetry() in presol_symmetry.h since this presolver does not compute symmetries independent
2857 of other components anymore
2858 + additional argument `recompute` to SCIPgetGeneratorsSymmetry() to allow recomputation of symmetries
2861 + the seed of SCIPinitializeRandomSeed() is now an unsigned int
2862 + the seed of SCIPsetInitializeRandomSeed() is now an unsigned int and it returns an unsigned int
2863 + new parameter for SCIPcreateRandom() to specify whether the global random seed shift should be used in the creation of
2864 the random number generator
2867 + additional arguments `preferrecent`, `decayfactor` and `avglim` to SCIPcreateBanditEpsgreedy() to choose between
2868 weights that are simple averages or higher weights for more recent observations (the previous default).
2869 The last two parameters are used for a finer control of the exponential decay.
2870 + functions SCIPintervalSolveUnivariateQuadExpression(), SCIPintervalSolveUnivariateQuadExpressionPositive(), and
2871 SCIPintervalSolveUnivariateQuadExpressionPositiveAllScalar() now take an additional argument to specify already
2872 existing bounds on x, providing an entire interval ([-infinity,infinity]) gives previous behavior
2874### New API functions
2876- SCIPintervalSolveUnivariateQuadExpressionNegative()
2877- SCIPvarGetNLocksDownType() and SCIPvarGetNLocksUpType()
2878- SCIPaddConsLocksType()
2879- SCIPconsIsLockedTypePos(), SCIPconsIsLockedTypeNeg(), SCIPconsIsLockedType(), SCIPconsGetNLocksTypePos() and SCIPconsGetNLocksTypeNeg()
2880- SCIPstrncpy(), a safe version of strncpy()
2882### Changed parameters
2884- Removed parameters:
2885 - `heuristics/alns/stallnodefactor` as the stall nodes are now controlled directly by the target node limit within the heuristic
2886 - `presolving/symmetry/computepresolved` since this presolver does not compute symmetries independent of other components anymore
2887 - `separating/maxincrounds`
2891- `lp/checkfarkas` that enables the check of infeasibility proofs from the LP
2892- `heuristics/alns/unfixtol` to specify tolerance to exceed the target fixing rate before unfixing variables, (default: 0.1)
2893- `propagating/orbitalfixing/symcomptiming` to change the timining of symmetry computation for orbital fixing
2894- `lp/alwaysgetduals` ensure that the dual solutions are always computed from the recent LP solve
2895- `display/relevantstats` indicates whether the small relevant statistics are displayed at the end of solving
2896- `propagating/orbitalfixing/performpresolving` that enables orbital fixing in presolving
2897- `presolving/symbreak/addconsstiming` to change the timining of symmetry computation for symmetry handling inequalities
2898- `propagating/orbitalfixing/enabledafterrestarts` to control whether orbital fixing is enabled after restarts
2899- `benders/∗` new submenu for Benders' decomposition related settings. This includes the settings related to the
2900 included Benders' decompositions and the general Benders' decomposition settings.
2901- `benders/<decompname>/benderscuts/∗` submenu within each included Benders' decomposition to control the Benders'
2902 decomposition cuts. The cuts are added to each decomposition separately, so the setting are unique to each
2907- new enum `SCIP_LOCKTYPE` to distinguish between variable locks implied by model (check) constraints (`SCIP_LOCKYPE_MODEL`)
2908 and variable locks implied by conflict constraints (`SCIP_LOCKYPE_CONFLICT`)
2909- expression interpreter objects are now stored in the block memory
2914- removed presolving plugin presol_implfree
2915- separated scip.c into several smaller implementation files scip_*.c for better code overview; scip.c was removed,
2916 but the central user header scip.h remains, which contains includes of the separated headers
2921- fixed bug in gcd reductions of cons_linear regarding an outdated flag for variable types
2922- fixed bug in heur_dualval regarding fixing routine for integer variables
2923- suppress debug solution warnings during problem creation stage
2924- fixed check for activated debugging solution in components constraint handler
2925- fixed potential bug concerning solution linking to LP in SCIPperformGenericDivingAlgorithm()
2926- fixed reward computation in ALNS on continuous, especially nonlinear, problems
2927- fixed bug in freeing reoptimization data if problem was solved during presolving
2928- fixed check of timing in heur_completesol
2929- fixed wrong propagation in optcumulative constraint handler
2930- fixed non-deterministic behavior in OBBT propagator
2931- don't disable LP presolving when using Xpress as LP solver
2932- fixed possible `NULL` pointer usage in cons_pseudoboolean
2933- ensured that SCIPgetDualbound() returns global dual bound instead of the dual bound of the remaining search tree
2934- fixed rare division-by-zero when solving bivariate quadratic interval equation
2935- use total memory for triggering memory saving mode
2936- fix parsing of version number in the CMake module for Ipopt
2937- fixed handling of implicit integer variables when attempting to solve sub-MIP in nlpdiving heuristic
2938- added workaround for bug when solving certain bivariate quadratic interval equations with unbounded second variable
2939- fixed bug with releasing slack variable and linear constraint in cons_indicator
2940- fixed problem when writing MPS file with indicator constraints with corresponding empty linear constraints
2941- fixed bug in heur_vbound triggered when new variables were added while constructing the LP
2942- fixed bug with unlinked columns in SCIProwGetLPSolCutoffDistance()
2947- updated CppAD to version 20180000.0
2948- remove LEGACY mode, compiler needs to be C++11-compliant
2950@page RN5 Release notes for SCIP 5
2952@section RN501 SCIP 5.0.1
2953*************************
2958- SCIP executable handles the `SIGTERM` signal. If the process receives a `SIGTERM`, SCIP terminates the solution process with a
2959 new `SCIP_STATUS` code `SCIP_STATUS_TERMINATE` and displays all relevant statistics before exiting.
2960- add number of conflict constraints found by diving heuristics to statistics
2961- allow output of lower bounds for visualization
2962- added symmetry detection for linking constraints
2964Performance improvements
2965------------------------
2967- disable disaggregation of quadratic constraints by changing the default for `constraints/quadratic/maxdisaggrsize` to 1
2968 (disaggregation can still be very helpful on some instances, but also seems hurtful on others)
2971 - increased threshold when to scale up cuts that are generated by nonlinear constraint handlers
2972 - test additional scaling factors in CMIR cut generation heuristic
2973 - cleaned up implementation of the cut selection procedure and added new cut quality measure
2974 - use random tie-breaking in cut selection
2979### New API functions
2981- new methods SCIPtryTerminate() and SCIPterminated() in scip/interrupt.h for handling of SIGTERM signals.
2982- new method SCIPselectCuts() to run SCIP's cut selection procedure on a given array of cuts
2984### Changed parameters
2986- rename parameter `constraints/orbisack/orbisack/coverseparation` to `constraints/orbisack/coverseparation`
2990- `visual/displb` that enables output of lower bounds for visualization
2991- `presolving/symmetry/displaynorbitvars` (whether we display the number of affected variables in the statistics)
2992- `separating/efficacyfac` to change the weight of the efficacy in cut score calculation
2993- `separating/dircutoffdistfac` to change the weight of the directed cutoff distance in cut score calculation
2997- new `SCIP_STATUS` code `SCIP_STATUS_TERMINATE` in scip/interrupt.h for handling of SIGTERM signals.
3002- expanded unit tests of the lpis
3003- added check to unit tests that problem is not solved after every change
3008- fixed LP status to unsolved when marking LP to be resolved if objective limit has changed
3009- copy parameter settings to sub-SCIPs in SCIPcopyLargeNeighborhoodSearch() also when copying only LP rows
3010- fixed a check for fixed variables in Binpacking example
3011- generate deprecation warnings when using SCIPaddCut
3012- fix bug in sepa_gomory if cut is a bound change
3013- fixed handling of infinite bounds in cons_sos1
3016 - fixed bug while scaling linear constraints
3017 - don't delete conflict constraints that were transformed into model constraints during a restart
3018 - fixed treatment of variable aggregations in knapsack constraint handler that led to wrong propagations
3021 - fixed LPI status after changing objective in lpi_cpx, lpi_grb, lpi_xprs, lpi_msk
3022 - fixed and unified asserts in LPIs
3023 - retrieve interior solution instead of (possibly non-existing) basic solution from mosek after using barrier without crossover in lpi_msk
3024 - fixed bug with `NULL` pointer handling in LPIs
3027 - fixed wrong cast in LP iteration limit computation in proximity search heuristic
3028 - fixed check for time limit in heur_nlpdiving
3029 - improved numerics and fixed stop criterion in zirounding heuristic
3031@section RN500 SCIP 5.0.0
3032*************************
3037- new numerical solution violations get printed when checksol is called
3038- added analysis of the clique table which identifies possible aggregations via the search for
3039 strongly connected components and may detect infeasible assignments on the way
3040- added macros to do computations with a higher precision by using double-double arithmetic
3041- extended conflict analysis by analyzing dual solutions of boundexceeding LPs
3042- revised internal debugging mechanism to check against a user given debug solution (debug.h)
3045 - add new heuristic MPEC that solves a MPEC reformulation of a mixed-binary nonlinear problem by regularized NLP reformulations
3046 - new primal heuristic ALNS that orchestrates eight different LNS heuristics adaptively
3047 using algorithms for the multi-armed bandit problem
3048 - three bandit selection algorithms to face sequential decision problems under uncertainty
3050- Presolving and symmetry:
3051 - added presol_symmetry.c for computing and storing symmetry information of a MIP
3052 - added presol_symbreak.c to detect special symmetry structures and to add symmetry handling constraints
3053 - SCIP can now automatically detect and compute symmetries in MIPs (if a graph automorphism code is linked in)
3054 - added cons_symresack.c to handle permutation symmetries in a binary programs via inequalities and propagation
3055 - added cons_orbisack.c to handle special permutation symmetries in a binary programs via inequalities and propagation
3056 - cons_orbitope.c can now handle full orbitopes as well
3059 - added new propagator orbital fixing
3060 - utilizing linear inequalities to compute stronger linearizations for bilinear terms; the inequalities are computed in
3064 - added API for aggregating rows for generating cuts which uses double-double arithmetic internally
3065 - added filtering of parallel cuts in the cut pool
3068 + added new plugin type `table` for adding user-defined statistics tables
3069 + new presolving plugin presol_sparsify that tries to cancel nonzero coefficients in linear constraints by adding
3070 multiples of linear equalities
3072Performance improvements
3073------------------------
3075- use disjoint set to reduce peak memory usage and time to compute of clique table connectedness information
3076- add and use RESTRICT macro for some pointers
3077- improved the implementation of SCIPvarGetActiveRepresentatives
3078- speed-up reverse propagation
3079- removed bestrelaxsol and directly access relaxation solution instead to decrease overhead when using relaxation handlers
3080- for fast presolving emphasis, disable use of implications in logicor presolving
3081- use limit on the total number of nonzeros added to the clique table during the greedyCliqueAlgorithm of cons_knapsack.c
3082- revised disaggregation of quadratic constraints: the number of created constraints can now be controlled and the
3083 disaggregated constraints are scaled in order to increase numerical accuracy
3084- disabled reformulation of products of a binary variable with a linear term that does not solely involve binary variables
3085- speed up creation of LP in the computation of relative interior points
3086- improved dual ray analysis
3087- drop events of disabled linear constraints to reduce event processing effort
3090 - new implementation of zerohalf separator
3091 - enabled cutting plane separation in the tree
3092 - improved cut selection and management
3093 - improved cut post-processing: apply coefficient tightening, enforce maximal dynamism
3096 - improved selection of rows in CMIR aggregation heuristic
3097 - generate lifted flowcover cuts in CMIR cut generation heuristic
3098 - faster implementation of CMIR cut generation heuristic
3099 - use LP solution polishing during probing and diving mode to activate it during many primal heuristics; remains disabled
3100 during strong branching and OBBT
3101 - improved versions of the clique and variable bound pre-root heuristics that are often able to fix many more variables
3106### New and changed callbacks
3109 - added new abstract selection algorithm `SCIP_BANDIT` together with callbacks
3110 - added new types for symmetry handling
3113 - dropped NLP termination status `SCIP_NLPTERMSTAT_UOBJLIM`
3116 - added parameter `objval` to `SCIP_DECL_NLPIGETSOLUTION` for returning the optimal objective value (can be set to `NULL`)
3118- Separation callbacks:
3119 - added parameter `allowlocal` to `SCIP_DECL_SEPAEXECLP` and `SCIP_DECL_SEPAEXECSOL` to switch generation of locally valid cuts
3120 - added parameter `dstatssize` to `SCIP_DECL_NLPIDELVARSET` and `SCIP_DECL_NLPIDELCONSSET`
3122### Deleted and changed API methods
3125 - removed parameter `allowaddcons` from SCIPselectVarPseudoStrongBranching(), SCIPselectVarStrongBranching(), and
3126 SCIPincludeBranchruleRelpscost()
3128- Constraint Handlers:
3129 - generalized SCIPcreateConsOrbitope() and SCIPcreateConsBasicOrbitope() method to three orbitope types (full, partitioning, packing)
3131- Cutting plane separation methods:
3132 - changed function signature of SCIPcalcMIR()
3133 - changed function signature of SCIPcalcStrongCG()
3134 - new method SCIPaddRow() to replace deprecated SCIPaddCut()
3135 - removed parameter `scaling` from SCIPgetRowprepViolation()
3136 - added parameter `allowlocal` to SCIPseparateSol()
3139 - replaced LP parameters `SCIP_LPPARAM_LOBJLIM` and `SCIP_LPPARAM_UOBJLIM` by `SCIP_LPPARAM_OBJLIM`
3142 - SCIPnlpStatisticsCreate() and SCIPnlpStatisticsFree() now require a pointer to blockmemory as parameter
3143 - added parameter `objval` to SCIPnlpiGetSolution() of NLPIs for returning the optimal objective value (can be set to `NULL`)
3144 - added parameter `varnameslength` to SCIPexprParse()
3145 - added parameter `dstatssize` to SCIPnlpiDelVarSet() and SCIPnlpiDelConsSet()
3146 - added modifier const to `exprtree` parameter of SCIPnlpiChgExprtree()
3149 - SCIPheurPassIndicator() has a new parameter which allows to pass the objective of the solution
3152 - added parameter `includeslp` to SCIPmarkRelaxSolValid(), SCIPsetRelaxSolVals() and SCIPsetRelaxSolValsSol();
3153 - removed parameter `includeslp` from SCIPrelaxCreate() and SCIPincludeRelax()
3154 - removed functions SCIPrelaxIncludesLp() and SCIPrelaxSetIncludesLp()
3155 - replaced method SCIPgetRelaxFeastolFactor() by SCIPrelaxfeastol() and added SCIPchgRelaxfeastol()
3158 - changed return type of SCIPcliqueGetId() from `int` to `unsigned int`
3159 - removed SCIPvarGetCliqueComponentIdx(); the connectedness information of the clique table is now stored as a
3160 `SCIP_DISJOINTSET` member of the clique table and cannot be publicly accessed
3161 - added parameter `copytables` to SCIPcopyPlugins()
3162 - SCIPsolveParallel() has been deprecated, use the new method SCIPsolveConcurrent() instead
3163 - allowed SCIPgetNConss() in stage `SCIP_STAGE_INITSOLVE`
3165### New API functions
3167- SCIPaddRow() to replace deprecated SCIPaddCut()
3168- methods to display linear constraint classification types; use SCIPclassifyConstraintTypesLinear()
3169 after reading a problem to classify linear constraint types
3170- public methods SCIPvariableGraphBreadthFirst() and SCIPvariableGraph{Create,Free}() to
3171 perform breadth-first search on the variable constraint graph used by the GINS and ALNS heuristics
3172- SCIPsetProbingLPState() to install given LP state and/or norms at the current probing node
3173- SCIPbranchcandGetLPMaxPrio() and SCIPbranchcandGetExternMaxPrio() to query the maximal branching priority of given
3174 branching candidates; also added SCIPbranchcandGetNPrioLPCands() to access the number of LP candidates with this priority.
3175- SCIPupdateSolIntegralityViolation(), SCIPupdateSolBoundViolation(), SCIPupdateSolLPRowViolation(),
3176 SCIPupdateSolConsViolation() and SCIPupdateSolLPConsViolation() for updating numerical solution violations, as well as
3177 SCIPactivateSolViolationUpdates() and SCIPdeactivateSolViolationUpdates() for activating/deactivating violation updates globally
3178- SCIPsetSubscipDepth() to set the depth of SCIP as a copied subproblem during problem stage
3179- SCIPdivesetGetNSols() to query the number of found solutions from a diveset.
3180- SCIPnextafter() that wraps different nextafter methods to return the next representable value after a given value
3181- SCIPlinConsStats{Create,Free,GetTypeCount,GetSum}() and SCIPprintLinConsStats() to work with linear constraint classification through the C API
3182- SCIPgetRowNumIntCols() that returns the number of integer columns in a row
3183- SCIPsetSlackVarUb() to control upper bound of slack variable in cons_indicator
3186 - methods SCIPrandomCreate() and SCIPrandomFree() are no longer public and should be replaced by SCIPcreateRandom() and
3187 SCIPfreeRandom(), respectively (the new methods respect the global parameter `randomization/randomseedshift` automatically)
3188 - methods SCIPdigraphCreate() and SCIPdigraphCopy() are no longer public and should be replaced by SCIPcreateDigraph() and
3189 SCIPcopyDigraph(), respectively, which receive a SCIP argument and are more robust towards future interface changes
3192 - SCIPgetAllBilinearTermsQuadratic() to access data of all existing bilinear terms in quadratic constraints
3193 - SCIPaddBilinearIneqQuadratic() to propose an inequality with two variables that appear in a bilinear term
3194 - SCIPcomputeBilinEnvelope{1,2}() to compute a linearization of a bilinear term when considering at most two linear inequalities
3197 - SCIPcliqueGetIndex() which returns the unique identifier for the given clique
3198 - SCIPgetNCliquesCreated() which returns the number of cliques created so far
3200- Cutting plane separation methods:
3201 - SCIPisCutNew() that returns whether a cut is already present in the global cut pool
3202 - SCIPgetSepaMinEfficacy() to access separating/minefficacy(root)
3205 - interface methods to create and use bandit algorithms implemented as SCIP core plugins
3206 - interface methods for aggregating rows and computating MIP cuts, see cuts.h
3207 - interface method SCIPsetRandomSeed() to (re)set a random number generator seed
3209### Command line interface
3211- new interactive shell functionality to display linear constraint classification types;
3212 use `display linclass` after reading a problem to classify linear constraint types
3213- new command line parameter `-r` to pass a nonnegative integer as random seed.
3215### Interfaces to external software
3217- added interface to the NLP solver WORHP
3218- added interface to the NLP solver FilterSQP
3219- added interface to graph automorphism algorithms in `src/symmetry/` (initially only to BLISS)
3220- unify handling of objective limit in LPIs by replacing LPI parameters `SCIP_LPPAR_LOBJLIM` and `SCIP_LPPAR_UOBJLIM` by
3222- dropped support for MOSEK < 7.0.0.0
3224### Changed parameters
3226- changed and removed several parameters for zerohalf separator
3227- replaced `constraints/quadratic/disaggregate` by `constraints/quadratic/maxdisaggrsize` to bound
3228 the total number of created constraints when disaggregating a quadratic constraint
3229- new value 3 for parameter `lp/solutionpolishing` to enable LP polishing only during probing and diving mode
3230- parameter `conflict/useboundlp` has new values `d` (only dual solution analysis) and `b` (both, conflict and dual solution analysis)
3233 - fixed typo `heuristics/completesol/maxunkownrate` has changed to `heuristics/completesol/maxunknownrate`
3234 - replaced parameter `heuristics/{clique,vbounds}/minfixingrate` by `heuristics/{clique,vbounds}/minintfixingrate` and
3235 `heuristics/{clique,vbounds}/minmipfixingrate`, which check the fixing rate before LP solving and after sub-MIP presolve
3238 - parameter `separating/maxstallrounds` only applies to nodes in the tree (not the root node, anymore); use the new
3239 parameter `separating/maxstallroundsroot` for the root node
3240 - moved parameters for flowcover and cmir separators to `separating/aggregation`
3242- Removed parameters:
3243 - `constraints/{abspower,bivariate,nonlinear,quadratic,soc}/scaling`
3244 - `constraints/{abspower,bivariate,quadratic,nonlinear}/mincutefficacysepa`
3245 - `constraints/{abspower,bivariate,quadratic,nonlinear}/mincutefficacyenfofac`
3246 - `constraints/soc/minefficacy`
3248 - `conflict/prefermir`
3249 - `heuristics/clique/{multiplier,initseed}`
3250 - `separating/feastolfac`
3251 - `separating/orthofac`
3252 - `separating/cgmip/allowlocal` (use parameter passed to separation callback instead)
3253 - `separating/{gomory,strongcg}/maxweightrange`
3257- `conflict/prefinfproof` (prefer infeasibility proof to boundexceeding proof)
3258- `conflict/sepaaltproofs`
3259- `constraints/indicator/maxsepanonviolated` to stop separation after separation of non violated cuts
3260- `constraints/orbisack/coverseparation` (whether orbisack cover inequalities should be separated)
3261- `constraints/orbisack/orbiSeparation` (whether facet defining inequalities for orbisack should be separated)
3262- `constraints/orbisack/coeffbound` (maximal value of coefficients in orbisack facet inequalities)
3263- `constraints/orbisack/checkpporbisack` (check whether orbisacks can be strengthened by packing/partitioning constraints)
3264- `constraints/orbisack/checkalwaysfeas` (whether conscheck returns always `SCIP_FEASIBLE`)
3265- `constraints/orbitope/checkpporbitope` (check packing/partitioning orbitopes)
3266- `constraints/orbitope/sepafullorbitope` (separate full orbitopes)
3267- `constraints/orbitope/checkalwaysfeas` (whether conscheck returns always `SCIP_FEASIBLE`)
3268- `constraints/quadratic/{usebilinineqbranch,minscorebilinterms,bilinineqmaxseparounds}`
3269- `constraints/quadratic/disaggrmergemethod` to change the strategy of how to merge independent blocks of quadratic constraints
3270- `constraints/quadratic/mincurvcollectbilinterms` to change the minimal curvature of constraints
3271 to be considered when returning bilinear terms to other plugins
3272- `constraints/quadratic/binreformbinaryonly` to disable reformulation of products of binary and non-binary variables
3273- `constraints/symresack/ppsymresack` (check whether symresacks can be strengthend by packing/partitining constraints)
3274- `constraints/symresack/checkalwaysfeas` (whether conscheck returns always `SCIP_FEASIBLE`)
3275- `expbackoff` to all separators which increases the frequency exponentially over the depth in the tree
3276- `heuristics/completesol/{beforepresol,maxlpiter,maxcontvars}`
3277- `heuristics/{clique,vbounds}/maxbacktracks` to limit the number of backtracks in the fix-and-propagate phase
3278- `heuristics/{clique,vbounds}/uselockfixings` to enable fixing of additional variables based on variable locks
3279- `heuristics/vbounds/{feasvariant,tightenvariant}` to specify the fixing variants used by the vbounds heuristic
3280- `lp/refactorinterval` to change the refactorization interval of the LP solver
3281- `misc/debugsol` to specify a debug solution that should be checked during the solve
3282- `misc/usesymmetry` to determine whether symmetry handling should be used
3283- `presolving/symbreak/conssaddlp` (whether symmetry handling inequalities should be added to the LP)
3284- `presolving/symbreak/addsymresacks` (whether symresacks should be used to handle symmetries)
3285- `presolving/symbreak/computeorbits` (whether symmetry orbits should be computed)
3286- `presolving/symbreak/detectorbitopes` (whether it should be checked if some symmetries can be handled by orbitopes)
3287- `presolving/symmetry/computepresolved` (Whether symmetries are computed after presolving)
3288- `presolving/symmetry/maxgenerators` (maximal number of generators generated by symmetry detection)
3289- `presolving/symmetry/checksymmetries` (whether validity of computed symmetries should be verified)
3290- `propagating/obbt/{itlimitfactorbilin,minnonconvexity,createbilinineqs}`
3291- `propagating/vbounds/minnewcliques` to specify the minimum number of new cliques to trigger another clique table analysis
3292- `propagating/vbounds/{maxcliquesmedium,maxcliquesexhaustive}` to limit the number of cliques relative to the
3293 number of binary variable for performing clique table analysis
3294- `separating/maxincrounds`
3295- `separating/maxlocalbounddist`, `separating/maxcoefratio` and `separating/intsupportfac`
3296- if PaPILO >= 2.1: `presolving/milp/maxbadgesizepar` to limit the maximal badge size if PaPILO is called in parallel mode
3297- if PaPILO >= 2.1: `presolving/milp/maxbadgesizeseq` to limit the maximal badge size if PaPILO is called in sequential mode
3301- new type `SCIP_Shortbool` (equal to uint8_t) for storing Boolean values in a more compact manner
3302- new disjoint set data structure `SCIP_DISJOINTSET` to incrementally update connectedness information for a graph on nodes {0,...,n-1}
3303- new red black tree data structure defined in `src/scip/rbtree.{c,h}`
3304- new object `SCIP_LINCONSSTATS`, see type_cons.h, to work with linear constraint classification through the C API
3305- added new type `SCIP_TABLE` together with callbacks to output SCIP statistics
3310- added several tests for the LP interface
3311- added tests that cover nonempty linear constraint classification types
3312- added tests for the double double arithmetic, the new red black tree data structure, the nlpi, obbt, interval arithmetics,
3313 symmetry computation, objective function changes in probing, computing envelopes of bilinear function, relaxation enforcement
3318- added interface to the NLP solver WORHP; set `WORHP=true` in order to link to WORHP
3319- added interface to the NLP solver FilterSQP; set `FILTERSQP=true` in order to link to FilterSQP
3323- added support for sanitizers in debug mode and options SANITIZE_ADDRESS, SANITIZE_MEMORY, SANITIZE_UNDEFINED, SANITIZE_THREAD
3324- added option SYM to specify which graph automorphism package (bliss, none) should be used, if available
3325- disable non-standard compliant floating point optimizations in combination with intel compilers
3326- improve Visual Studio compilation
3327- only accept IPOPT version 3.12.0 or higher
3328- preserve correct rpath in library (e.g. path to libipopt) when installing
3332- new flag `DEBUGSOL={true,false}` to enable checks against a user given debug solution
3333- added flag SYM to specify which graph automorphism package (bliss, none) should be used
3334- default value for ZIMPL in the Makefile is now `false`
3339- fix wrong statistic display of diving leaf solutions
3340- fixed order of SCIPcalcCliquePartition() in corner case where no cliques are available
3341- fix treatment of infinite lower bound in proximity objective cutoff
3342- fixed minor issue in expression graph simplification
3345 - fix linear knapsack relaxation during separation if a binary variable does not have a solution value in [0,1].
3346 - fixed potential ressource leaks in SCIPsolveLinearProb(), expr.c, sepa_eccuts, cons_cumulative.c, cons_nonlinear.c
3347 - fixed bug in cons_orbitope.c, where wrong terminating index in separation of SCIs was used
3348 - fixed wrong mapping of permuted basis indices in gomory separator
3349 - fixed integer objective separator for objective scales < 1
3352 - fixed numerical issues in boundshift presolver when aggregating integer variables
3353 - fixed aggregation of variables in boundshift presolver that contain large variable bounds
3356 - fixed bug in feasibility pump heuristic when switching on the `usefp20` parameter
3357 - fixed handling of LOOSE variables in locks heuristic
3358 - fixed creation of conflicts in clique heuristic for incomplete LPs
3361 - fixed bug in mps reader. Reader now prints `OBJSENSE` section and tries to generate unique names of constraints
3362 - fixed upgrade to a varbound constraint if abspower constraint contains a multi-aggregated variable
3363 - fixed several bugs related to hashing of constraints/rows in cutpool.c and cons_linear.c
3364 - fixed registration of almost fixed nonlinear variables in abspower constraints
3367 - fixed releasing of variables in the genvbounds propagator in case the problem could be solved during presolving of a restart
3368 - fixed numerical issues in bound widening of variable bound constraint handler and vbound propagator during conflict analysis
3370@page RN4 Release notes for SCIP 4
3372@section RN401 SCIP 4.0.1
3373*************************
3378- added parsing functionality to cardinality constraint handler for CIP format
3379- allow to relax objective limit in reoptimization in presolved stage
3380- suppress excessive printing about numerical troubles in LP on default verblevel (high)
3382Performance improvements
3383------------------------
3385- only accept passed improving solutions in heur_indicator
3386- add and use RESTRICT macro for some pointers
3387- sorting of parents and children for some expression types is now independent of memory layout
3390 - widened a bottleneck in simplifying long signomial sums in a nonlinear constraint
3391 - unified and extended code that improves numerics of cuts generated by nonlinear constraint handlers
3394 - stop separation in cons_indicator after maxsepanonviolated many non violated separated cuts
3395 - improve choice of variable to enter support in separation of cons_indicator
3400### New API functions
3402- SCIPvalidateSolve() to compare solving result with an external primal and dual reference value
3403- SCIPisObjChangedProbing() to check whether the objective function has changed during probing mode
3404- SCIPgetDualSolVal() to get the dual solution value of a constraint
3405- SCIPisLPPrimalReliable() and SCIPisLPDualReliable() to check whether the current primal / dual LP solution
3406 were successfully checked for feasibility
3408### Command line interface
3410- New option in the interactive shell to validate the solution against an external primal and dual reference value
3411- added command line option `-o` and command `validatesolve` in interactive shell
3412 to validate the solution against an external primal and dual reference value.
3414### Interfaces to external software
3416- Updated and new interfaces to Mosek 8.1, GAMS and Gurobi
3417- new LP interface to Glop (Google OR tools); CMake only
3419### Changed parameters
3421- renamed parameter `heuristics/completesol/maxunkownrate` to `heuristics/completesol/maxunknownrate`
3426- add options to make test target (see Makefile section)
3433- New CMake build system alongside the usual Makefile setup
3437- added make options for specifying EXECUTABLE and OUTPUTDIR variables for the make test target
3442- fixed unintended behavior of interrupt signal handler inside SCIP copies
3443- fixed uninitialized values in SCIP's digraph data structure after calling SCIPdigraphResize()
3444- fixed issue related to SCIPcreateFiniteSolCopy() not being able to remove all infinite fixings
3445- fixed issue in SCIPcopyLimits() w.r.t. soft time limit
3446- fixed bug in dynamic resizing of hashtables and hashmaps
3447- added workaround for bug in primal simplex of cplex 12.7.1.0 occuring when attempting to solve LPs without rows without presolving
3448- fixed bug in binpacking example that might have led to doing the same branching several times
3449- fixed memory issue in binpacking example
3450- in GAMS writer, forbid also various parenthesis characters in gams symbol names
3451- added missing definition of `SCIP_UNUSED` in memory.h if def.h is not included
3452- treat reopt bugs: Avoid numerical problems with changing objective; fix check for changed objective
3453- fixed reading issue in mps reader: integer variables fixed to 0 or 1 are treated as binaries now,
3454 allowing to use them as indicator variables
3455- afternode heuristics are now called even if the node limit was reached and the solving process will be stopped
3456 after the current node
3457- fixed bug when activating probing mode with a non-empty separation storage
3460 - fixed guard against using old Gurobi versions in lpi_grb.c: Gurobi 7.5 was not permitted
3461 - fixed wrong handling of unboundedness status in lpi_grb.c
3462 - fixed wrong handling of row basis status in lpi_grb.c
3465 - fixed bug in shift and propagate--variable information with a negation transformation is correctly reset after backtracking
3466 - fixed bug in genvbounds propagator when applying a restart after the root node
3469 - fixed bug in varbound coefficient tightening: if a varbound constraint only contained one variable afterwards,
3470 it may have been deleted without applying the induced bound, if the change was too small, this is now forced
3471 - fixed potential wrong locks update after a varbound constraint became redundant in coefficient tightening
3472 - fixed potentially wrong cleanup of fixed variables in nonlinear constraint handler
3473 - fixed memory leak in OSiL reader when using SOS constraints
3476 - improved handling of infinite values in a primal solution in quadratic and nonlinear constraints
3477 - fixed bug in computing violation and cut for certain nonlinear constraints when LP solution is slightly out of bounds
3478 - fixed debug solution check that appeared in probing mode when the objective function has changed
3479 - relaxed a too strong assert concerning solutions close to the objective limit
3481@section RN400 SCIP 4.0.0
3482*************************
3487- Introduced support for partial or infeasible user solutions, which SCIP tries to complete/repair heuristically
3488- implemented linear time methods for (weighted) median selection for joint arrays of various types
3489- added adaptive solving behavior of SCIP based on solving phases and heuristic transitions, if enabled via `solvingphases/enabled`
3490- can now solve relaxations within probing
3491- in case of multiple relaxators the best solution is saved instead of the last one
3492- added write callback for reader_bnd
3493- added possibility to use a reference value for advanced analysis of the tree search. If a finite reference value
3494 (an objective value in original objective space) is passed via misc/referencevalue, SCIP keeps track of the
3495 number of nodes exceeding the reference value and the number of early backtracks -- path switches in the tree when
3496 a child node with lower bound smaller than the reference value was available.
3497- added reading capabilities for partial solutions with extension *.mst
3498- new global shift off all random seeds (randomization/randomseedshift) and unification of all existing random seeds
3499- use new macros SCIPdebugMsg(), SCIPsetDebugMsg(), SCIPstatDebugMsg() at all places where it makes sense
3500- new random number generator in pub_misc.h
3501- add check whether variables have been released when freeing SCIP
3502- a print callback can now be specified for user expressions
3505 - will now enforce relaxation solution instead of lp or pseudosolution if lowerbound is better and the whole lp is included in the relaxation
3506 - new feature solution polishing to improve integrality of LP solutions
3509 - new constraint handler for cardinality constraints
3510 - added interval-evaluation of sine and cosine
3511 - allow to create constraints of constraint handlers that don't need constraints
3512 - New constraint handlers cardinality and components
3515 - implement a storage for conflicts to have more control over active conflicts
3516 - Improved conflict analysis through central conflict pool and dual ray analysis for primal infeasible LPs; can now analyze dual
3517 unbounded rays of primal infeasible LPs
3520 - New presolvers that disaggregate SOC constraints and reformulate QP's by adding KKT conditions
3521 - new presolving step for variables contained in a single quadratic constraint with proper square coefficients
3522 - add new presolving step to disaggregate second order cone constraints
3523 - new presolving method presol_qpkktref to add the KKT conditions of a QP
3524 - implemented and extended stuffing presolving in linear constraint handler
3525 - new components constraint handler which replaces the components presolver; it searches for independent subproblems
3526 and solves small ones as sub-SCIPs during presolve, larger ones are solved alternatingly during the main solving process
3527 - new presolving timing FINAL: presolving methods with this timing are only called once after all other presolvers with timings
3528 FAST, MEDIUM and EXHAUSTIVE are finished; during this timing only reductions are allowed that are self-contained, e.g.,
3529 fixing all variables and deleting all constraints of an independent component; note that reductions found in this timing
3530 do not trigger a new presolving round
3532- Separation and Cuts:
3533 - can now separate perspective cuts for indicator constraints
3534 - add sepa_convexproj, a separator which projects onto convex relaxation and build gradient cuts at the projection
3535 - add sepa_gauge, a separator which computes an interior point of a convex relaxation and performs a binary search in the segment joining
3536 the interior point and the point to separate until it finds a point in the boundary of the feasible region where to build a gradient cut
3537 - changed handling of coupling constraints in cons_indicator; the cuts will not be added to the pool, but are separated by default
3538 - concurrent solving mode that allows to run multiple SCIP instances, that share solutions and global variable bounds, in parallel
3539 - Revised pseudo random number generation and introduced central random seed for all plugins
3542 - new Graph induced neighborhood search (GINS) primal heuristic that uses neighborhoods
3543 based on distances in the variable constraint connectivity graph.
3544 In addition, the heuristic supports a rolling horizon-like procedure to solve auxiliary problems
3545 for neighborhoods with increasing distance from the starting neighborhood.
3546 - new primal heuristic LP face that tries to find an integer solution inside the optimal LP face.
3547 - new heuristic that tries to complete partial solutions
3548 - the subnlp heuristic now gives ownership of a found solution to the heuristic that constructed the starting point, if any;
3549 as a consequence, MIP heuristics may now be shown more frequently for having found a solution when solving MINLPs, even
3550 though the solutions required an additional NLP solve
3551 - new multistart heuristic for NLPs
3554 - add prop_nlobbt, a nonlinear optimization-based bound propagator solving two convex NLP relaxations for each variable
3555 - nodes can now be postponed; currently, this can only be triggered by BEFORELP propagation callbacks
3558 + Extended statistic output displayable via the interactive shell
3559 + new statistic computed: `Root LP Estimate` that shows the root LP best-estimate with every pseudo-cost update
3560 + added leaf statistics about LP objective limit|feasible|infeasible leaves to the statistics output and
3561 to the callable library: SCIPgetNObjlimLeaves(), SCIPgetNFeasibleLeaves(), SCIPgetNInfeasibleLeaves()
3562 + next to the number of found solution, also the number of new best solutions is now printed for each heuristic
3563 (and relaxation solutions) in the statistics in the `Primal Heuristic` section.
3565Performance improvements
3566------------------------
3568- Extended the presolving timings by an additional timing FINAL for self-contained reductions
3569- Randomized tie-breaking in different parts of the code to reduce performance variability
3570- use connectedness information of the clique table to speed up the clique partitioning algorithm
3571- knapsack approximation algorithms use linear-time weighted median selection instead of sorting
3572- improved greedy solution in SCIPsolveKnapsackApproximatelyLT() for the flow cover separation
3573- reduce performance variability by using random numbers as tie-breaker for external branching candidates
3576 - adjusted most Large Neighborhood Search heuristics such that they collect their variable fixings first in an array,
3577 and only create and populate a sub-SCIP if enough variables will be fixed.
3578 - reduce performance variability by using a small perturbation in the undercover heuristic
3579 - 1-opt heuristic can now be repeatedly executed as long as new incumbents are found
3582 - Improved and extended stuffing inside of linear constraint handler
3583 - Changed handling of coupling constraints in cons_indicator
3584 - SCIP supports constraint compression for problem copies; constraint compression denotes the immediate
3585 removal of fixed variables from constraint data at creation time to reduce memory requirements.
3588 - rewrote the propagate-and-cut-and-price loop so that successful propagations with DURINGLPLOOP timing, bound changes found by separation,
3589 and new primal solutions now trigger a new round of node solving, starting with propagation; improved tuning of propagation and heuristic timings
3590 - tuned propagation methods of several constraint handlers
3591 - make more use of SCIPmarkConsPropagate() to mark constraints for propagation and improved the internal handling of marked constraints
3592 - improve propagation of absolute-value expression in the case that the sign of the argument is fixed
3597### New and changed callbacks
3600 - extended interface to support concurrent solving mode
3602- Constraint Handlers:
3603 - new optional callback `CONSENFORELAX` to enforce a relaxation solution, see \ref CONS
3604 - `CONSINITLP` callback now has a new parameter `infeasible`, which is a pointer to store whether infeasibility
3605 was detected while building the initial LP relaxation
3607### Deleted and changed API methods
3609- setting a parameter to a non-valid value now produces an error message instead of a warning
3610- bound reader uses angle bracket around variable names
3611- the parameters of SCIPlpiChgObj(), SCIPlpiSetBase(), SCIPlpiSetState(), SCIPlpiSetNorms() have been declared as const
3612- SCIPapplyHeurSubNlp() can now return the solution found by the sub-NLP heuristic
3615 - methods SCIPrandomGetInt() substitutes SCIPgetRandomInt() (marked to be deprecated)
3616 - methods SCIPrandomGetReal() substitutes SCIPgetRandomReal() (marked to be deprecated)
3617 - methods SCIPrandomPermuteArray() substitutes SCIPpermuteRandomArray() (marked to be deprecated)
3618 - methods SCIPrandomPermuteIntArray() substitutes SCIPpermuteRandomIntArray() (marked to be deprecated)
3619 - method SCIPrandomGetSubset() substitutes SCIPgetRandomSubset() (marked to be deprecated)
3622 - added parameters `conftype` and `iscutoffinvolved` to SCIPinitConflictAnalysis()
3623 that indicate the type of the conflict and whether the current cutoff bound is used or not
3625- Constraint Handlers:
3626 - added parameter `infeasible` to SCIPinitlpCons()
3629 - added parameters `fixedvars`, `fixedvals`, `nfixedvars` to SCIPcopyVars()
3630 - added parameters `fixedvars`, `fixedvals`, `nfixedvars` to SCIPcopyOrigVars()
3631 - renamed parameter `success` to `valid` in SCIPgetConsCopy()
3633- Hashmap and Hashtable:
3634 - removed function SCIPcalcHashtableSize() since not required anymore for `SCIP_HASHTABLE` and `SCIP_HASHMAP`
3635 - based on the initial size `SCIP_HASHTABLE` and `SCIP_HASHMAP` choose an appropriate size internally to allow insertion of that
3636 many elements without resizing
3637 - `SCIP_MULTIHASH` behaves like the old `SCIP_HASHTABLE` and SCIPcalcMultihashSize() should be used as replacement for
3638 SCIPcalcHashtableSize()
3640- Nonlinear Relaxation:
3641 - added parameter `curvature` to SCIPcreateNlRow()
3644 - the following new methods return a bool indicating whether the given value is valid for the parameter instead of printing a warning
3645 message and returning an error code if the value is invalid
3646 - renamed method SCIPcheckBoolParam() to SCIPisBoolParamValid()
3647 - renamed method SCIPcheckLongintParam() to SCIPisLongintParamValid()
3648 - renamed method SCIPcheckCharParam() to SCIPisCharParamValid()
3649 - renamed method SCIPcheckStringParam() to SCIPisStringParamValid()
3650 - renamed method SCIPcheckRealParam() to SCIPisRealParamValid()
3651 - in param.c/h: the new methods return a bool whether the given value is valid for the parameter instead of printing a warning message
3652 and returning an error code if the value is invalid
3653 - rename SCIPparamCheckBool() to SCIPparamIsValidBool()
3654 - rename SCIPparamCheckString() to SCIPparamIsValidString()
3655 - rename SCIPparamCheckChar() to SCIPparamIsValidChar()
3656 - rename SCIPparamCheckLongint() to SCIPparamIsValidLongint()
3659 - added parameter `initialseed` to SCIPcreateDiveset()
3660 - introduced new type `SCIP_HEURTIMING` for primal heuristic timing masks
3661 - changed type of parameter `timingmask` from unsigned int to `SCIP_HEURTIMING` in SCIPincludeHeur(), SCIPincludeHeurBasic()
3664 - new parameter `includeslp` for SCIPincludeRelax() and SCIPincludeRelaxBasic()
3665 to indicate whether relaxation includes all linear rows and can be enforced
3668 - rename method SCIPgetReopSolsRun() to SCIPgetReoptSolsRun()
3671 - added parameter `completely` to SCIPtrySol(), SCIPtrySolFree(), SCIPcheckSol() to check all constraints when
3675 - removed SCIPvarGetLbAtIndex() and added SCIPgetVarLbAtIndex()
3676 - removed SCIPvarGetUbAtIndex() and added SCIPgetVarUbAtIndex()
3677 - removed SCIPVarGetBdAtIndex() and added SCIPgetVarBdAtIndex()
3678 - removed SCIPvarWasFixedAtIndex() and added SCIPgetVarWasFixedAtIndex()
3679 - Removed method SCIPvarGetNBinImpls()
3681### New API functions
3683- added functions for concurrent solving mode (see concurrent.h, concsolver.h)
3684- SCIPcreateNlpiProb(), SCIPupdateNlpiProb() and SCIPaddNlpiProbRows() to create and update a nonlinear relaxation
3685- SCIPgetNObjlimLeaves(), SCIPgetNFeasibleLeaves(), SCIPgetNInfeasibleLeaves() for statistics output
3686 about LP objective leaves
3687- SCIPcheckCopyLimits() which can be used to check that enough time and memory is left to run a sub-SCIP after
3688 subtracting time and memory used by the main-SCIP and SCIPcopyLimits() which copies these limits accordingly and disables
3689 all other limits (need to be set by the plugin, if needed)
3690- SCIPcopyLargeNeighborhoodSearch() in heuristics.h that supports compressed copying and two kinds of problem copy: the MIP-relaxation or
3691 a 1-1 problem copy (by copying the constraints and not the LP relaxation)
3692- SCIPsolveProbingRelax() to solve a relaxation within probing
3693- SCIPgetLastStrongbranchingLPSolstat() to query the LP statuses after strong branching on a variable
3694- SCIPinitializeRandomSeed()
3695- SCIPswapReals() to swap two real values
3696- SCIPgetNNZs() to get the number of active non-zeros in the transformed/presolved problem
3699 - SCIPprintDebugMessage(), SCIPsetPrintDebugMessage(), SCIPstatPrintDebugMessage() that output debug messages and also print the
3700 subscip depth; the first two output via the message handler; also added macros SCIPdebugMsg(), SCIPsetDebugMsg(), SCIPstatDebugMsg()
3701 - SCIPdebugMsgPrint()/SCIPsetDebugMsgPrint() that output a message without `[debug]` prefix via the message handler (compare SCIPdebugPrintf())
3704 - SCIPisDualSolAvailable() to query the dual solution availability
3705 - SCIPlpiSetIntegralityInformation() to improve SoPlex' solution polishing
3708 - library methods SCIPcopyConsCompression(), SCIPcopyOrigConsCompression() that accept an array of variables that are immediately
3709 fixed in the copy. Alternatively, local instead of global bounds can be used for compression.
3710 - library methods SCIPenableConsCompression(), SCIPisConsCompressionEnabled(), SCIPcopyConsCompression(), SCIPcopyOrigConsCompression()
3711 - SCIPgetIntVarXor() to access integer variable of XOR constraints
3712 - SCIPcreateConsCardinality() to create a cardinality constraint
3713 - SCIPcreateConsBasicCardinality() to create a basic cardinality constraint
3714 - SCIPchgCardvalCardinality() to changes cardinality value of cardinality constraint (i.e., right hand side of cardinality constraint)
3715 - SCIPaddVarCardinality() to add a variable to a cardinality constraint
3716 - SCIPappendVarCardinality() to append a variable to a cardinality constraint
3717 - SCIPgetNVarsCardinality() to get the number of variables in a cardinality constraint
3718 - SCIPgetVarsCardinality() to get the array of variables in a cardinality constraint
3719 - SCIPgetCardvalCardinality() to get the cardinality value of a cardinality constraint (i.e., right hand side of cardinality constraint)
3720 - SCIPgetWeightsCardinality() to get the array of weights of a cardinality constraint
3721 - SCIPgetLinvarMay{Decrease,Increase}Quadratic() to get index of a variable in linear term of quadratic constraint that may be decreased
3722 without making any other constraint infeasible
3725 - add SCIPparamIsValidInt() and SCIPparamIsValidReal() to param.c/h
3726 - add missing functions SCIPisIntParamValid() and SCIPisRealParamValid() to scip.c/h
3728### Command line interface
3730- new command line parameter `-v` to print detailed build options
3732### Interfaces to external software
3734- Interfaces for Python and Java are, among others, now available via http://www.github.com/scip-interfaces
3735- Revised documentation of the SCIP C-API to group methods more comprehensively by topics
3736- dropped support for Ipopt < 3.11
3737- Additional I/O-functionalities for debugging and logging in SCIP and in the AMPL interface
3738- updated CppAD to 20160000
3739- for users of the ampl interface, the display/logfile option has been added to set the name of a
3740 file to write the SCIP log to (additionally to stdout)
3743 - SCIP uses the lpi_spx2 interface by default
3744 - Improved Gurobi interface that can handle ranged rows (requires Gurobi >= 7.0.2)
3745 - the CPLEX LPI now also compiles with CPLEX 12.7.0.0
3747### Changed parameters
3749- setting a value for a fixed parameter will no longer return with an error, if the new value equals the one to which the parameter is fixed
3750- changed value of parameter `separating/clique/cliquedensity` to 0.0 such that the separator always constructs a dense clique table
3751 which proved to be faster on the benchmarks MMM and stableset.
3752- parameters `misc/permutationseed`, `misc/permuteconss` and `misc/permutevars` changed to `randomization/permutationseed`,
3753 `randomization/permuteconss` and `randomization/permutevars`
3754- parameters `conflict/useinflp` and `conflict/useboundlp` are now of type char (before bool)
3755- all parameters of the components presolver (starting with `presolving/components/`) are now parameters of the components
3756 constraint handler (starting with `constraints/components/`)
3760- class randomization
3761- `branching/sumadjustweight` to adjust branching scores by adding a sum epsilon in order to keep score differences
3762 near zero, which are otherwise completely disregarded (they are adjusted to at least sum epsilon)
3763- `concurrent/∗ ` and `parallel/∗ ` for configuring the concurrent solving mode
3764- `constraints/cardinality/branchbalanced` to decide whether to use a balanced branching scheme in the enforcing of cardinality
3766- `constraints/cardinality/balanceddepth` to set the maximal depth until balanced branching is turned off
3767- `constraints/cardinality/balancedcutoff` to determine that balanced branching is only used if the branching cut off value
3768 w.r.t. the current LP solution is greater than a given value
3769- `constraints/indicator/sepaperspective` to turn on separation of perspective cuts for indicator constraints
3770- `constraints/indicator/sepapersplocal` to decide whether local cuts can be used for perspective cuts for indicator constraints
3771- `constraints/quadratic/projectedcuts` to enable convex quadratics to generate gradients cuts at the
3772 projection of the point onto the region described by the constraint, which is supporting
3773- `lp/solutionpolishing` to enable LP polishing only at the root LP or always
3774- `misc/referencevalue` to pass a reference value for further analysis of the tree search, see also in `features`
3775- `presolving/qpkktref/addkktbinary` to allow the presence of binary variables for the KKT update
3776- `presolving/qpkktref/updatequadbounded` to add the KKT conditions to QPs only if all variables are bounded
3777- `presolving/qpkktref/updatequadindef` to add the KKT conditions to QPs only if the quadratic matrix is indefinite
3778- `randomization/lpseed` to set the initial seed of the LP solver
3779- `solvingphases/enabled` to activate adaptive behavior during the solution process; several further parameters
3780 in the solvingphases-section to control how to switch the parameters and whether a restart should be performed between the phases.
3784- new `SCIP_REGRESSION` data structure in pub_misc.h to incrementally compute a best-fit line through pairs of observations
3785- add maximum branch-and-bound tree depth constant `SCIP_MAXTREEDEPTH` (replaces SCIPgetDepthLimit() and SCIPtreeGetDepthLimit())
3786- new files heuristics.c/heuristics.h to collect methods that are frequently used by heuristics
3787- merged dive.c/pub_dive.h with heuristics.c/heuristics.h, removed dive.c/pub_dive.h
3788- separated header pub_misc.h from repeated methods for sorting and (weighted) median selection;
3789 those are also available in separate headers pub_misc_sort.h
3790 and pub_misc_select.h, but included into pub_misc.h
3795- New unit testing system built on the Criterion framework
3802- All makefiles in `examples/` and `applications/` have been updated.
3803- `make.project` defines a variable `SCIP_VERSION` containing the SCIP version number
3804- revise sub-makefiles for MSVC on MinGW
3805- make shared libraries aware of their dependencies
3806- sub-makefile for CrayXC systems added
3809 - All objective files are now placed in `obj/static` or `obj/shared`, depending on `SHARED=false` or `SHARED=true`, respectively.
3810 - All internal and external libraries are placed in `lib/static` and `lib/shared`, the include files are in `lib/include`.
3811 - The binaries now contain an rpath to the SCIP directory, such that shared libraries are found.
3814 - link binary to shared libs when compiling with `SHARED=true`
3815 - External projects (including make.project) can use the makefile variable LINKCXXSCIPALL or LINKCCSCIPALL to link all SCIP libraries.
3816 - Building with `SHARED=true` automatically generates the combined library libscipsolver.so for easier linking
3819 - Running `make help` lists all makefile options.
3820 - `make install` copies now all header files
3821 - new target `dll` to build Windows dlls with MSVC
3822 - rename `dll` target to `windowslib`
3827- fixed bug in event system: bound change events of the new focus node must be processed, even if the bound
3828 is the same as at the last focus node
3829- avoid numerically unstable (multi-)aggregations
3830- fixed bug in XML reader concerning comments
3831- the AMPL interface now writes a solve status (solve_result_num) into the .sol file
3832- in the cmpres.awk (allcmpres.sh) output, the counts in the time column are now with respect to the
3833 whole set of processed instances (as with fail and solv), while before it was with respect to the
3834 set of instances where no solver failed (eval set); thus, now proc = fail + time + solv.
3835- writing of solutions or parameters to a file now works also with the message handler set to quiet
3836- ignore lower and upper bound tightenigs beyond +/-infinity during solving
3837- time limit of SCIP-infinity is converted to LPI-infinity when setting it
3838- fix LP activity of a row that has been modified
3841 - fixed possible segmentation fault in genvbounds propagator
3842 - fixed bug with sorting of propagators in presolving: the order can be changed by calling probing; thus, there is a copy of the
3843 propagators, which is sorted by presolving priority
3844 - added missing capturing and releasing mechanism in genvbounds propagator
3845 - fix wrong propagation of product expressions
3848 - fixed wrong representation of SOC constraints in NLP
3849 - fixed a few issues within redundant constraint detection of (specialized) linear constraint handlers
3850 - fixed issue in reader_opb concerning writing of fixed variables contained in no constraints
3853 - fixed memory bug in `SCIP_DIGRAPH`
3854 - improved counting of memory consumption by using more block memory and counting all allocated memory
3855 - fix memory leaks in TSP example
3856 - return `SCIP_ERROR` when a memory exception is caught in SoPlex (was `SCIP_LPERROR`)
3857 - fixed memory leak in OSiL reader
3860 - fixed bug while changing the objective value of an original value after transforming the problem
3861 - fixed bug with solutions from previous runs not satisfying an objective limit
3862 - SCIPisObjIntegral() now works correctly in `SCIP_STAGE_PROBLEM`
3865 - fixed two bugs in heur_indicator: use improvesols parameter now and update pointer to indicator constraint handler
3866 - fix wrong NLP representation of logic-or constraints in the dual value heuristic
3867 - correct handling of implicit integer variables with fractional solution value in simplerounding heuristic
3868 - fixed bug in heur_octane with uninitialized ray direction
3870@page RN3_2 Release notes for SCIP 3.2
3872@section RN321 SCIP 3.2.1
3873*************************
3878- new `force` parameter in (root)redcost propagator to run the propagator also with active pricers
3880Performance improvements
3881------------------------
3883- do not transfer solutions to original space, if SCIP is being freed
3884- modified implication graph analysis of SOS1 constraint handler; a new component allows to deduce zero fixings of variables
3885- made SOS1 constraint handler specific diving selection rule faster for the case that the SOS1 constraints do not overlap
3886- improved disjunctive cuts by the `monoidal cut strengthening` procedure of Balas and Jeroslow
3888Examples and applications
3889-------------------------
3891- several improvements of SCIP-Jack (STP application): extended presolving for STP variants, STP-specific branching
3892 rule, dual heuristic to generate initial LP relaxation
3893 SCIP-Jack is now competitive with problem specific state-of-the-art solvers on several well-known STP variants,
3894 e.g., the (rooted) prize-collecting Steiner tree problem.
3895- MultiObjective application renamed to PolySCIP; several improvements: better command line argument processing,
3896 overhaul of much of the source code, installation via CMake
3901- made debug solution functionality thread safe (see debug.h for further information)
3903### Deleted and changed API methods
3905- add SCIPcomputeHyperplaneThreePoints() to compute a hyperplane containing three given 3-dimensional points
3906- SCIPsolveLinearProb() now uses a 1-dimensional matrix representation
3908### Command line interface
3910- added interactive shell command `display finitesolution` to print solution with infinite fixings removed,
3911 added reference to that method to `display solution` output if there are infinite fixings
3912- new interactive shell command `write history` to write the command line history (only when compiled with Readline)
3914### Interfaces to external software
3916- significantly improved Python interface to support user callbacks as well as linear and quadratic expressions
3920- `constraints/sos1/branchingrule` to decide whether to use neighborhood, bipartite, or SOS1 branching (this parameter
3921 replaces the old parameters `constraints/sos1/neighbranch`, `constraints/sos1/bipbranch`, and `constraints/sos1/sos1branch`)
3922- `constraints/sos1/depthimplanalysis` to limit the number of recursive calls of implication graph analysis
3923- `constraints/sos1/perfimplanalysis` to perform an implication graph analysis to deduce variable fixings and
3924 additional SOS1 constraints (this parameter replaces the old parameter `constraints/sos1/updateconflpresol`)
3925- `misc/transsolorig` for transfering transformed solutions to the original space (default: true)
3926- `propagating/rootredcost/onlybinary` to propagate root reduced costs of binary variables only
3930- renamed MIP matrix structure to `SCIP_MATRIX`
3931- changed the numeric values for `PRESOLTIMING` flags
3938- new target `dll` to build Windows dlls with MSVC
3939- add new compiling flag OPENSOURCE to allow/forbid the usage of third party software
3944- fixed wrong objective sense when copying the original problem
3945- fixed a bug in merge step of cliques during clean up phase; method did not correctly handle infeasibility in the case of multiple
3946 variable-negation pairs
3947- fixed a previously untreated case in the linear cons simplification where coefficients only differ by slightly more than an epsilon
3948- fixed bug in parsing emphasis parameters which formerly led to completely wrong results
3949- fixed bug in the computation of the Wilcoxon test
3950- do not use the relative and absolute gap limit if no primal solution has been found so far
3951- fixed bug in conflict.c with wrong reset of bounds used
3952- fixed bug with transferring solutions to new runs (need to recompute objective before checking)
3953- fixed issue with infinite values when checking cuts for redundancy
3954- fixed library problems on Windows operating systems
3957 - fixed wrong check when computing cuts for factorable quadratic functions bound tightening of a single variable
3958 - fixed wrong handling of loose variables in OBBT
3959 - fixed freeing of hash for binary variables
3960 - fixed bug during the computation of branching points for continuous variables which are almost fixed to +/- SCIPinfinity()
3961 - treated the case of integer variables as intermediate variables in the process of obtaining the active variable for a
3962 given binary variable
3965 - fixed a bug in dive.c that occurred when lpsolvefreq was set to 1; after a cutoff, the solution values of the
3966 linked LP solution might have become invalid
3967 - do not analyse an infeasible LP for conflicts during diving mode when LHS/RHS of rows were changed
3968 - use LPi infinity when reverting bound changes in conflict analysis
3971 - fixed bug in heur_simplerounding in connection with relaxators
3972 - fixed bug in feaspump heuristic where last solution candidates were not updated correctly
3973 - fixed bug with infinite shift values in heur_shifting
3974 - fixed bug in shiftandpropagate heuristic: the heuristic did not correctly handle intermediate, global bound changes of the selected variable
3975 after its tentative fixing led to a cutoff.
3978 - (root) reduced cost propagators are not run anymore when doing branch-and-price,
3979 since they may install upper bounds on variables which might interfere with the
3980 pricing (they may be enabled again by their force parameters)
3981 - fixed too hard assertion in pseudoobj propagator
3982 - fixed a bug in shiftandpropagate where column positions after sorting are now correctly linked to their variables after sorting
3983 - fixed potential memory leak in genvbound propagator
3986 - fixed inconsistency in knapsack constraint handler data during presolving
3987 - fixed some problem with reoptimization when the problems are infeasible or have been solved in presolving
3988 - fixed endless loop in knapsack constraint handler when continuous variables change their types to binary during presolving
3989 - squares of binary variables might not have been replaced by the binary variable itself in presolve,
3990 if the variable was originally general integer and only became binary during presolve (due to bound tightening)
3991 - fixed bug in dive.c avoiding a check of constraints in the presence of indicator constraints
3994 - fixed numerical problems in computation of cuts for bivariate functions in quadratic constraint handler
3995 - fixed bug in quadratic constraint handler when computing lifted-tangent inequalities
3996 - fixed bug in nonlinear constraint handler when replacing a violated nonlinear constraint leads to an infinite
3997 - fixed bug in SOS1 constraint handler with inconsistent data structure after restart
3998 - fixed wrong handling of negated variables in bound tightening procedure of SOS1 constraint handler
3999 - fixed bug in simple fixing heuristic of SOS1 constraint handler
4000 - fixed two bugs in pseudoboolean constraint handler with wrong sorting of and constraints
4001 - fixed issue: constraints being parallel to objective function (after restart) sometimes led to wrongly stating infeasible
4002 - fixed bug during coefficient tightening in varbound constraint handler
4003 - handle cutoffs in cons_indicator detected by infeasible inequalities
4004 - fixed late change of type of slack variables in cons_indicator, if the bounds are not integral
4005 - fixed initsol and exitsol of cons_indicator, if problem has already been solved
4006 - fixed bug in cons_indicator with changing type of slackvariable
4008@section RN320 SCIP 3.2.0
4009*************************
4014- added reoptimization feature for optimization problems with changed objective function or tighter feasible region
4015- the original problem can now be permuted directly after reading (if `misc/permutationseed` has value >= 0)
4016- added methods to compute strongly connected components with Tarjan's Algorithm
4017- added method to propagate implications of SOS1 variables
4018- convex quadratic contraints can now generate gradient cuts which are supporting to the feasible region
4019- SoPlex interface can now (re)store dual steepest edge weights
4020- extended expression parsing to support power, realpower and signpower operators; started support for user-defined operators
4021 in expression trees/graphs
4022- possibility to set a soft time limit which becomes active only after the first primal solution was found
4023- added matrix module for getting access to the internal mixed inter linear problem matrix
4024- better handling of large values returned by the LP solver
4025- added more checks to SCIP{alloc,realloc,duplicate}BufferArray() to handle overflows properly
4026- new plugin for reoptimizing a sequence of optimization problem that differ in the objective function, e.g., sequences arising from
4028- new plugin `compr` for rearranging the search tree, currently this only works on the reoptimization tree
4029- moved assertions in comparison methods from scip.c to set.c
4032 - we can now upgrade quadratic constraints with one bilinear term to SOC constraints
4033 - we can also upgrade general quadratic constraints with a single negative eigenvalue to SOC constraints
4036 - tighter reliability notions introduced for reliability branching, based on pseudo-cost relative errors
4037 and comparing candidates with the best pseudo-candidate using a 2-sample student-T test. These methods
4038 are used in disjunction with the existing reliability notion that uses a fixed number as reliability
4039 threshold for every variable before turning off strong-branching. This means, the classical method
4040 must be turned off by setting parameters minreliable and maxreliable to 0. The behavior is
4041 controlled through several parameters.
4042 - new distribution branching rule to base decisions on row activity (normal) distribution over domain space
4043 - can now output information for BAK: Branch-and-bound Analysis Kit
4044 - new score in hybrid reliability pseudocost branching that prefers nonlinear variables when solving MINLPs
4045 - new branching rule multaggr which allows to branch on general disjunctions defined by fractional multi-aggregated variables
4046 - new branching rules for SOS1 constraints for branching on a neighborhood or a complete bipartite subgraph of
4047 the conflict graph. In addition to variable domain fixings, it is sometimes also possible to add complementarity
4048 constraints to the branching nodes. This results in a nonstatic conflict graph, which may change dynamically
4049 with every branching node.
4050 - new branching rule nodereopt to reconstruct the tree after changing the objective function
4053 - the MPS reader can now read semi-integer variables, they are handled by creating bound disjunction constraints
4054 - the MPS reader can now handle objective constants given as (the negation of) the RHS of the objective row
4057 - obbt propagator applies now additional separation and propagation in order to learn stronger and more bound tightenings
4058 - extended probing mode to allow separation and objective coefficient changes
4059 - improved separation procedure of SOS1 constraint handler, including bound (clique) cuts and implied bound cuts
4060 - new disjunctive cut separator for SOS1 constraints
4061 - new edge-concave cut separator for quadratic constraints
4064 - Improved coordination of presolvers. There are three timings for presolvers now, FAST, MEDIUM and EXHAUSTIVE.
4065 Each presolving callback can specify one or more of these timings in which it will be called later.
4066 Within a presolving method, the current timing can be checked and the algorithms to be performed selected based on
4067 the timing. In one presolving round, first all presolving methods with timing FAST are called, sorted by priority.
4068 If they found enough reductions, a new round is started, otherwise, all presolving methods with timing MEDIUM are
4069 called. Again, with enough reductions, a new presolving round is started, too few reductions lead to running
4070 the EXHAUSTIVE presolvers. Similar to the delay concept used before, we are not neccessarily running all EXHAUSTIVE
4071 presolvers but stop as soon as one of them found enough reductions, starting a new presolving round immediately.
4072 - new presolving components for SOS1 constraints, including bound tightening and clique extension
4073 - new presolver tworowbnd for improving variable bounds and detecting redundant constraints added
4074 - new presolver dualagg for aggregating single up-/downlocked variables by a binary variable added
4075 - new presolver implfree for aggregating implied free variables added
4076 - new presolver redvub which can detect redundant variable upper bound constraints added
4077 - new presolver stuffing for fixing of singleton continuous variables added
4080 - improved clique and variable bound heuristics
4081 - new heuristic distribution diving that bases its score function on the changes regarding solution density
4082 - variable histories can be transferred between sub-SCIPs solved by LNS heuristics and the component presolver
4083 and the main SCIP to reuse this information.
4084 - new heuristic heur_indicator that tries to make partial solutions with indicator constraints feasible. It also
4085 tries to improve them (or external solutions) by a one-opt local search.
4086 - new heuristic (heur_bound) which fixes all integer variables to their lower/upper bounds and solves the remaining LP
4087 - modified diving heuristics to handle SOS1 constraints
4088 - new primal heuristic for reoptimization 'ofins': objective function induced neighborhood heuristic
4089 - new heuristic for reoptimization which constructs solutions based in the changes between the objective function and the optimal
4090 solution before changing the objective function
4093 - extended variable branching statistics in the interactive shell by sample variance of unit gains
4094 - extended statistic output of interactive shell by more information on diving heuristic behavior
4096Performance improvements
4097------------------------
4099- improved treatment of nonlinearities in hybrid reliability pseudo cost branching
4100- using sparsity information of the SoPlex LP
4103 - improved vartype upgradability from continuous to implicit variables in cons_linear.c, depending on their objective coefficients
4104 - improved propagation of SOS1 constraint handler using the information from a conflict
4107 - zi rounding heuristic uses buffer data structures, thereby decreasing total memory usage of SCIP
4108 - adjusted (hard) diving heuristics to solve fewer LPs. LP's are resolved only if a parameter-defined
4109 percentage of the variable bounds changed through domain propagation or at a predefined frequency.
4110 - some of the diving heuristics additionally consider indicator variables and SOS1 variables as candidate variables and try to
4111 make these constraint types feasible before passing a rounded solution to SCIPtrySol()
4114 - new presolving/propagation algorithm using the gcd for ranged rows and equations in cons_linear
4115 - added presolving levels (FAST, MEDIUM and EXHAUSTIVE) to allow better balancing of presolvers
4118 - improved separation procedure of SOS1 constraint handler
4119 - improved separation procedure for convex quadratic constraints
4121Examples and applications
4122-------------------------
4124- two new applications for multi-objective optimization (PolySCIP) and the Steiner Tree Problem in Graphs
4125- new application for solving Steiner tree problems: SCIP-Jack can handle both the classical Steiner tree problem in graphs
4126 and 10 of its variants
4131### New and changed callbacks
4133- new callback function `SCIP_DECL_CONSGETDIVEBDCHGS` to provide
4134 constraint handler method to suggest dive bound changes during the generic diving algorithm, see type_cons.h for details
4135- new callback `SCIP_DECL_DIVESETGETSCORE` to implement scoring function to guide diving
4137### Deleted and changed API methods
4139- avoid potential comparisons of different infinity values by adjusting the LP solution value
4140- SCIPintervalSign(), SCIPintervalAbs(), SCIPintervalMax(), SCIPintervalMin(), SCIPexprgraphGetNodePolynomialMonomialCurvature(),
4141 and SCIPexprgraphTightenNodeBounds() need an infinity value to decide whether an interval is empty or not
4142- SCIPgetFeasibilityQuadratic() and SCIPgetActivityQuadratic() returns now a `SCIP_RETCODE` and needs an additional `SCIP_Real*` to
4144- methods which support statistical tests in pub_misc.h, SCIPstudentTGetCriticalValue(), SCIPcomputeTwoSampleTTestValue() etc.
4145- SCIPsolveLinearProb() solves a linear problem of the form Ax=b for a regular square matrix A
4146- Added parameter `freesubscip` to SCIPapplyProximity()
4149 - Renamed method SCIPdigraphGetSuccessorsDatas() to SCIPdigraphGetSuccessorsData()
4150 - Renamed method SCIPdigraphGetNodeDatas() to SCIPdigraphGetNodeData()
4151 - Renamed method SCIPdigraphSetNodeDatas() to SCIPdigraphSetNodeData()
4153- Constraint Handlers:
4154 - Renamed method SCIPconshdlrGetPropTimingmask() to SCIPconshdlrGetPropTiming()
4155 - new method SCIPconshdlrSetPropTiming()
4156 - Removed method SCIPconshdlrIsPresolvingDelayed()
4157 - Removed method SCIPconshdlrWasPresolvingDelayed()
4158 - SCIPmakeSOS1sFeasible() based on solution values, fixes variables to zero to turn all SOS1 constraints feasible
4159 - removed `delay(presol)` parameter from SCIPinclude{Conshdlr,Presol,Prop}() and added `(presol)timing` parameter
4160 - new parameter `presoltiming` for method SCIPpresolCons()
4161 - SCIPvarIsSOS1() returns whether some variable is involved in an SOS1 constraint
4162 - SCIPgetConflictgraphSOS1() gets conflict graph of SOS1 constraints
4163 - Added parameter `presoltiming` to SCIPpropCumulativeCondition()
4164 - Removed parameter `delaypos` from SCIPsetConshdlrPresol()
4165 - Added parameter `presoltiming` to SCIPsetConshdlrPresol()
4166 - Removed parameter `delaypos` from SCIPincludeConshdlr()
4167 - Added parameter `presoltiming` to SCIPincludeConshdlr()
4168 - Added parameter `consgetdivebdchgs` to SCIPincludeConshdlr() to provide a divebdchg-callback for the constraint handler
4172 - Added parameter `forcestrongbranch` to SCIPselectVarStrongBranching()
4173 - Added parameter `executebranching` SCIPexecRelpscostBranching()
4174 - Added parameters `ndomredsdown` and `ndomredsup` to SCIPgetVarStrongbranchWithPropagation()
4176- LP and Cutting Planes:
4177 - Added parameters `inds` and `ninds` to SCIPgetLPBInvRow(), SCIPgetLPBInvCol(), SCIPgetLPBInvARow(), SCIPgetLPBInvACol(), and
4179 - Added parameters `maxweight`, `weightinds`, `nweightinds`, and `rowlensum` to SCIPcalcMIR()
4182 - SCIPvarGetNodeSOS1() returns node of SOS1 variable in the conflict graph
4183 - SCIPnodeGetVarSOS1() returns SOS1 variable associated to some given node in the conflict graph
4184 - Removed method SCIPvarGetNBinImpls()
4187 - Removed parameter `delaypos` from SCIPincludePresolBasic()
4188 - Added parameter `presoltiming` to SCIPincludePresolBasic()
4189 - Removed parameter `delaypos` from SCIPincludePresol()
4190 - Added parameter `presoltiming` to SCIPincludePresol()
4191 - Removed parameters `presoldelay` and `presoltiming` from SCIPincludePresol()
4192 - Removed parameters `presoldelay` and `presoltiming` from SCIPsetPropPresol()
4195 - Added parameter `isequation` to SCIPaddClique()
4196 - Removed parameter `writeimplications` from SCIPwriteCliqueGraph()
4197 - Removed method SCIPallocBufferSize()
4198 - Removed method SCIPduplicateBufferSize()
4199 - Removed method SCIPreallocBufferSize()
4200 - Removed method SCIPfreeBufferSize()
4201 - Removed method callback SCIPdialogExecConflictgraph()
4203### New API functions
4205- started support for user-defined operators in expression trees/graphs (see SCIPexprCreateUser()),
4206 interface will likely change again in future SCIP versions
4207- new methods for mixed inter linear matrix access (see pub_matrix.h) added
4208- SCIPcomputeArraysIntersection() to compute the set intersection of two ordered arrays
4209- SCIPcomputeArraysSetminus() to compute the set difference of two ordered arrays
4210- SCIPcutGetLPActivityQuot() in pub_cutpool.h to get the potion of LP's where this cut was sharp in an optimal basis.
4211- SCIPpresolGetTiming(), SCIPpresolSetTiming(), SCIP{conshdlr,prop}GetPresolTiming(), and SCIP{conshdlr,prop}SetPresolTiming()
4212- SCIPdigraphSetNSuccessors() sets the number of successors of some digraph node to a given value
4215 - SCIPcreateDiveset() to add a diveset to a heuristic. Heuristics may have multiple divesets under different names
4216 - SCIPperformGenericDivingAlgorithm() that performs diving with periodic LP resolve according to the diveset argument.
4219 - new setter function SCIPsetConshdlrGetDiveBdChgs() in scip.h to set dive bound change callback for this constraint handler
4220 - SCIPaddDiveBoundChange() to add a diving bound change to the diving bound change storage of SCIP together with the information if this is a
4221 bound change for the preferred direction or not, to be used by constraint handlers inside the getDiveBdChgs-callback
4222 - SCIPchgCoefLinear() and SCIPdelCoefLinear() to modify linear constraint during problem creation
4225 - BMSallocClearBlockMemoryArray()/SCIPallocClearBlockMemoryArray() and
4226 BMSallocClearBufferMemoryArray(), SCIPallocClearBufferArray() to allocate arrays that are initialized to 0
4227 - SCIPbuffermem() to get buffer memory;
4230 - added new sorting functions SCIPsortRealRealRealBoolBoolPtr(), SCIPsortDownRealRealRealBoolBoolPtr()
4231 - added new sorting functions SCIPsortIntIntIntReal(), SCIPsortDownIntIntIntReal(), SCIPsortRealIntInt(), SCIPsortDownRealIntInt()
4234 - SCIPwriteParam() to write a single parameter to a file
4235 - SCIPcheckParam{Bool,Char,...}() to check whether a parameter value is within the feasible domain
4238 - SCIPchgLhsQuadratic(), SCIPchgRhsQuadratic(), SCIPchgLinearCoefQuadratic(), SCIPchgSquareCoefQuadratic(),
4239 and SCIPchgBilinCoefQuadratic() to modify quadratic constraints during problem creation
4240 - SCIPgetFeasibilityQuadratic() and SCIPgetActivityQuadratic() to get the feasibility and activity of a quadratic constraint in a given solution
4241 - SCIPaddSquareLinearization(), SCIPaddSquareSecant(), SCIPaddBilinLinearization() and SCIPaddBilinMcCormick()
4242 in cons_quadratic.h to compute linear under- and overestimation for bilinear and quadratic terms
4244### Command line interface
4246- extended variable branching statistics and statistic output in the interactive shell (see Statistic section)
4247- submenu for setting `vbc` settings renamed to `visual`
4248- at the end of a command line run the best solution can now be output in the orignal space
4250### Interfaces to external software
4252- in the AMPL interface, variable and constraint attributes (flags) can now be set via suffixes, where 0 (unset) stands
4253 for the default, 1 for TRUE and other values for FALSE; see SCIPcreateVar() and SCIPcreateCons() for their meaning;
4254 for variables, `initial` and `removable` are recognized;
4255 for constraints, `initial`, `separate`, `enforce`, `check`, `propagate`, `dynamic` and `removable` are recognized
4256- the AMPL interface now passes an initial guess, if specified, as a solution (that will be checked for feasibility) to SCIP
4258### Changed parameters
4260- rowrepswitch set to 2.0, so row representation is activated if LP has at least 2 times more rows than columns
4261- one can now set emphasis parameters at the beginning of a settings file; it should start with `emphasis:` and
4262 the contain the emphasis string, e.g., `emphasis: feasibility` or `emphasis: heuristics off`.
4264- Renamed parameters:
4265 - `vbc/filename` to `visual/vbcfilename`
4266 - `vbc/realtime` to `visual/realtime`
4267 - `vbc/dispsols` to `visual/dispsols`
4271- added parameter to switch pseudo cost update in diving heuristics (enabled by default)
4272- `branching/relpscost/confidencelevel` to set the confidence level to be used by statistical tests
4273- `branching/relpscost/higherrortol` to define the highest reliability threshold for relative error based reliability
4274- `branching/relpscost/lowerrortol` to define a lower reliability threshold for relative error based reliability
4275- `branching/relpscost/nlscoreweight` for weight of nonlinear score when branching on MINLPs
4276- `branching/relpscost/usedynamicconfidence` to use a dynamic confidence level based on the amount of
4277 strong-branching simplex-iterations compared to the overall simplex iterations (default is FALSE)
4278- `branching/relpscost/usehyptestforreliability` to enable strong branching decisions based on a 2-sample student-T test of all prior
4279 pseudo-cost observations between the best pseudo-candidate and the candidate for which to decide whether strong-branching should be applied
4280- `branching/relpscost/userelerrorreliability` to enable relative error based reliability
4281- `branching/relpscost/skipbadinitcands` for skipping strong-branching candidates whose estimated gain
4282 is significantly worse than the one of the locally best (sb or pseudo) candidate
4283- `constraints/linear/multaggrremove` to perform multi-aggregations in linear constraint handler only if the constraint can be removed afterwards
4284- `constraints/linear/rangedrowpropagation` to disabled newly implemented propagtion algorithm for ranged rows and equations
4285- `constraints/quadratic/advanced/interiorcomputation` to select the way of computing and interior point for gauge cuts
4286- `constraints/quadratic/gaugecuts` to enable convex quadratics to generate gradients cuts which are supporting
4287- `constraints/soc/generalsocupgrade` to allow general quadratics to be upgraded to soc
4288- `constraints/SOS1/addcomps` to add local complementarity constraints to the branching nodes (can be used in combination
4289 with neighborhood or bipartite branching)
4290- `constraints/SOS1/addbdsfeas` to define a minimal feasibility value for local bound (clique) inequalities in order to be
4291 added to the branching node
4292- `constraints/SOS1/addcompsdepth` to define the maximal depth for adding complementarity constraints
4293- `constraints/SOS1/addcompsfeas` to define a minimal feasibility value for local complementarity constraints in order to be
4294 added to the branching node
4295- `constraints/SOS1/autocutsfromsos1` to automatically switch to separating bound cuts from SOS1 constraints if the SOS1
4296 constraints do not overlap
4297- `constraints/SOS1/autosos1branch` to switch to SOS1 branching if the SOS1 constraints do not overlap
4298- `constraints/SOS1/conflictprop` to define whether to use conflict graph propagation
4299- `constraints/SOS1/bipbranch` to branch on a complete bipartite subgraph of the conflict graph
4300- `constraints/SOS1/boundcutsdepth` to define the node depth of separating bound (clique) cuts
4301- `constraints/SOS1/boundcutsfreq` to define the frequency for separating bound (clique) cuts
4302- `constraints/SOS1/boundcutsfromgraph` to define whether to separate bound (clique) inequalities from the conflict graph
4303- `constraints/SOS1/boundcutsfromsos1` to define whether to separate bound (clique) inequalities from SOS1 constraints
4304- `constraints/SOS1/fixnonzero`: If neighborhood branching is used, then fix the branching variable (if positive in sign)
4305 to the value of the feasibility tolerance
4306- `constraints/SOS1/implcutsdepth` to define the node depth of separating implied bound cuts
4307- `constraints/SOS1/implcutsfreq` to define the frequency for separating implied bound cuts
4308- `constraints/SOS1/implprop` to define whether to use implication graph propagation
4309- `constraints/SOS1/maxaddcomps` to define the maximal number of complementarity constraints added per branching node
4310- `constraints/SOS1/maxboundcuts` to define the maximal number of bound (clique) cuts separated per branching node
4311- `constraints/SOS1/maxboundcutsroot` to define the maximal number of bound (clique) cuts separated per iteration in the root node
4312- `constraints/SOS1/maximplcuts` to define the maximal number of implied bound cuts separated per branching node
4313- `constraints/SOS1/maximplcutsroot` to define the maximal number of implied bound cuts separated per iteration in the root node
4314- `constraints/SOS1/maxextensions` to define maximal number of extensions that will be computed for each SOS1 constraint in presolving
4315- `constraints/SOS1/maxsosadjacency` to define that the adjacency matrix of the conflict graph is not created in presolving if
4316 the number of SOS1 variables is too large
4317- `constraints/SOS1/maxtightenbds` to define the maximal number of bound tightening rounds per presolving round
4318- `constraints/SOS1/neighbranch` to branch on a neighborhood of the conflict graph
4319- `constraints/SOS1/nstrongiter` to define the maximal number LP iterations to perform for each strong branching round
4320- `constraints/SOS1/nstrongrounds` to define the maximal number of strong branching rounds to perform for each node (only
4321 available for neighborhood and bipartite branching)
4322- `constraints/SOS1/sos1branch` to branch on a single SOS1 constraint, i.e., a clique of the conflict graph
4323- `constraints/SOS1/sosconsprop` to define whether to use SOS1 constraint propagation
4324- `constraints/SOS1/strthenboundcuts` to define whether to strengthen bound (clique) cuts in case bound variables are available
4325- `constraints/SOS1/updateconflpresol` to update the conflict graph during the presolving procedure
4326- `display/allviols` to print all violated constraints of the best solution during checksol in the scip shell
4327- `heuristics/indicator/improvesols` that turns on the improvement of external solutions by one-opt
4328- `heuristics/∗diving/lpresolvedomchgquot` to determine the percentage of changed domains since previous LP to trigger
4329 an LP resolve [default: 0.15] (* stands for eight diving heuristics to support this feature)
4330- `heuristics/∗diving/lpsolvefreq` to determine the frequency for resolving LP's during the execution of
4331 this heuristic [default: 1, use 0 for a dynamic setting based on the number of domain reductions]
4332 (* stands for eight diving heuristics to support this feature)
4333- `heuristics/shiftandpropagate/binlocksfirst` to set if binaries without locks should be preferred in ordering
4334- `heuristics/shiftandpropagate/maxcutoffquot` to select a maximum percentage of allowed cutoffs before stopping the heuristic (default is 0.0)
4335- `heuristics/shiftandpropagate/selectbest` to trigger if shiftandpropagate should select the best candidate in every round
4336 (set to FALSE for static order) (default is FALSE)
4337- `limits/autororestart` for triggering an automatic restart after this many nodes, or -1 for no auto restart [default is -1]
4338- `limits/softtime` to set a soft time limit (active only after first primal solution was found)
4339- `misc/allowobjprop` to allow objective function propagation
4340- `misc/allowdualreds` to allow dual reductions
4341- `misc/outputorigsol` to control whether at the end of a command line run the solution should be output in the orignal space
4342- `numerics/checkfeastolfac` to scale feasibility tolerance when checking the feasibility of best found solution
4343 after the solving process finished (e.g., checksol in scip shell)
4344- `separating/cutselrestart` for cut selection during restart copy process (`a`ge, activity `q`uotient) [default is `a`]
4345- `separating/cutselsubscip` for cut selection for sub SCIPs (`a`ge, activity `q`uotient) [default is `a`]
4346- `separating/disjunctive/maxconsdelay` to delay separation of disjunctive cuts if number of SOS1 constraints is larger than predefined value
4347- `separating/disjunctive/maxdepth` to define the node depth of separating disjunctive cuts
4348- `separating/disjunctive/maxinvcuts` to define the maximal number of disjunctive cuts investigated per iteration in a branching node
4349- `separating/disjunctive/maxinvcutsroot` to define the maximal number of disjunctive cuts investigated per iteration in the root node
4350- `separating/disjunctive/maxrank` to define the maximal permissible rank of a disjunctive cut that could not be scaled to integral coefficients
4351- `separating/disjunctive/maxrankintegral` to define the maximal permissible rank of a disjunctive cut that could be scaled
4352 to integral coefficients
4353- `separating/disjunctive/maxrounds` to define the maximal number of separation rounds of disjunctive cuts in a branching node
4354- `separating/disjunctive/maxweightrange` to define the maximal valid range of simplex tableau row weights
4358- new enum `SCIP_CONFIDENCE_LEVEL` for different levels of confidence for statistical tests.
4359- new struct `SCIP_DIVESET` that bundles options for SCIP's diving heuristics; all hard diving heuristics (those
4360 without `obj` at the beginning) include diveset and implement only the scoring callback.
4361- rename all file `*_vbc.?` to the more generic `*_visual.?`
4362- moved buffer memory handling to blockmemory/memory.?;
4363 remove files type_buffer.h, struct_buffer.h buffer.h buffer.c;
4364 removed functions SCIP*buffer*() from scip.? and replaced them by macros;
4365 redesigned buffer interface to be similar to block memory; added checks for strange sizes
4370- added scripts and targets for testing with xpress (see Makefile section)
4377- new parameter `DELHEADERS` for `uninstall`-target: scip headers are only removed when invoking `make uninstall DELHEADERS=true`
4378- added scripts check_xpress.awk, check_xpress.sh, evalcheck_xpress.sh and check_cluster_xpress.sh and target
4379 `testclusterxpress` and `testxpress`
4384- fixed bug in primal.c and tree.c by using SCIPinfinity() as a cutoffbound to delete child nodes
4385- fixed bug in lp.c which leads to wrong primal and dual feasibility
4386- fixed wrong handling of infinite activities and primal values in sepastore.c and lp.c
4387- fixed bug that led to an erroneous warning about the clock type
4388- fix behavior of `make install` which now sets symbolic links and short links to binaries and libraries
4389- fix bug which lead to wrong global bound tightenings in prop_genvbounds.c
4390- fix call to random generator for Windows operating systems in misc.c
4391- fixed again a bug in backward propagation of linear expressions in expression graph
4392- fixed bug in prop_symmetry.c, where an incorrect weak symmetry handling constraint got added.
4395 - fixed bug in heur_nlpdiving.c: wrong counting of fix variables
4396 - fix wrong handling of `SCIP_NLPSOLSTAT_LOCALINFEASIBLE` solution status in nlp.c
4397 - fix characterization of logic or constraints in SCIP's NLP relaxation
4400 - fixed wrong comparison when executing branching rule for external branching candidates
4401 - fix spatial branching on implicit integer variables
4402 - fix wrong comparisons of values larger/less than +/- SCIPinfinity() in branch.c, lp.c and sol.c
4403 - fixed problem with lpisrelax flag in probing mode when doing branch-and-price
4405- Constraint Handlers:
4406 - try to handle fixings of multi-aggregated variable in cons_sos1 presolving and avoid error
4407 - fixed bug in pseudoboolean constraint handler about negated variables
4408 - fixed assert in cons_soc.c: now soc with 1 lhs variable are allowed
4409 - fixed wrong assert in cons_indicator (slack variables might be replaced by active variables that have nonzero objective)
4410 - fix late creation of auxiliary LP in cons_nonlinear.c, which lead to a segmentation fault with lpi_spx2.cpp
4411 - fixed bug in cons_abspower.c: do not generate cuts with infinity right-hand-side anymore
4412 - fixed setting of enforcement flag for constraints created by reformulation in nonlinear constraint handlers
4413 - fixed bug in cons_indicator with handling local bounds
4416 - fix potential memory leak in SoPlex LP interfaces when setting invalid basis
4417 - fix potential memory leak in method SCIPgetConsCopy()
4418 - fix potential memory leak in method detectRedundantConstraints() of the knapsack constraint handler
4420- Interval arithmetic:
4421 - fix handling of infinite intervals in SCIPintervalIsEmpty()
4422 - fixed bug in intervalarith.c: bivariate quadratic equations may have been solved wrongly if second variable is unbounded
4424- Quadratic Constraints:
4425 - fix wrong sorting of bilinear terms in cons_quadratic
4426 - fix potentially tightening of LB/UB of a variable to +/- infinity in cons_quadratic
4427 - fixed bug in cons_quadratic.c which leads to an overflow when SCIP allocates memory for a dense matrix
4428 - fixed bug in cons_quadratic.c: do not generate linearization cuts for disabled constraints
4429 - fix missing clean phase of bilinear terms with zero coefficient in cons_quadratic.c
4431@page RN3_1 Release notes for SCIP 3.1
4433@section RN311 SCIP 3.1.1
4434*************************
4439- use clock average to reduce number of system calls via `timing/rareclockcheck` parameter
4440- added copy mechanism for conjunction constraints
4441- added revised lpi_xprs for using XPRESS as LP solver
4443Performance improvements
4444------------------------
4446- improved solving of LPs in OBBT propagator
4447- improved activity-delta computation and thereby propagation for linear constraints
4448- improved memory management of proximity heuristic
4449- disabled statistic timing in all subscips via new parameter `timing/statistictiming`
4454### New and changed callbacks
4456- rename array arcdatas in digraph to arcdata
4457- changes in clock type are now transferred to SoPlex
4458- corrected wrong primal bound in statistics for unbounded problems
4459- forbid to call SCIPfixVar() in `SCIP_STAGE_PRESOLVED` stage, which is not allowed since it calls SCIPchgVarLb/Ub()
4461### Deleted and changed API methods
4463- rename SCIPdigraphGetNodeDatas() to SCIPdigraphGetNodeData();
4464- rename SCIPdigraphSetNodeDatas() to SCIPdigraphSetNodeData()
4465- SCIPapplyProximity() has an additional parameter freesubscip, which causes the method to free
4466 the created subscip automatically at the end.
4468### New API functions
4470- SCIPhasPerformedPresolve() to check, e.g., whether LP duals are accessible
4471- SCIPconvertRealTo[Long]Int() to convert reals that represent integers to [long] ints.
4472- SCIPisDualfeasEQ() and related to perform checks w.r.t. to the dual feasibility tolerance
4473- SCIPdeleteSubproblemProximity() to free proximity subproblem manually as external caller
4475### Command line interface
4477- added dialog for writing the finite solution (calling SCIPcreateFiniteSolCopy() before writing)
4479### Interfaces to external software
4481- AMPL interface now returns dual multipliers if problem is an LP and presolving was turned off
4483### Changed parameters
4485- changed default value of parameter `heuristics/proximity/minimprove` to 0.02; previous value was 0.25
4486- changed default value of parameter `heuristics/proximity/usefinallp` to FALSE
4490- `timing/rareclockcheck` to call the system time less frequently, based on the current average time interval
4491 between two calls to SCIPsolveIsStopped(); the default value is FALSE
4492- `timing/statistictiming` to enable/disable all timers for statistic output of SCIP; the default value is TRUE
4496- renamed MIP matrix structure to `SCIP_MATRIX`
4497- changed the numeric values for `PRESOLTIMING` flags
4504- added Makefile support for cygwin 64 Bit
4505- allow to turn off block and buffer memory by the makefile parameters NOBLKMEM, NOBUFMEM, NOBLKBUFMEM;
4506 also remove the now superfluous makefiles for noblkmem, nobufmem, noblkbufmem
4511- fixed wrong conversion of reals representing negative integer values
4512- in debug mode, SCIP checks that no NaN's are introduced in SCIPsolSetVal()
4513- fixed bug 697 (and 699), calling SCIPsolve() after the problem was already solved and SCIPfreeSolve() was called now
4514 does nothing anymore
4515- added support for character `#` in variable names in old non-linear CIP format (i.e., names without `<` and `>`)
4516- fixed bug 702, removed too hard assert when casting too big values into `SCIP_Longint`
4517- branching for continuous variables with unbounded intervals now takes `branching/clamp` into account
4518- forbid aggregations with scalar smaller feastol or larger 1/feastol
4519- fixed bug 683, not recognizing errors/segfaults especially in free stage of SCIP by improving the check scripts
4520- fixed bug where quieting a message handler also disabled writing to files other than stdout
4521- fixed bug 708, special case of implications led to a fixing
4522- fixed bug, variable bounds detected wrong infeasibility
4523- another bug fix when computing the original variable sum of a given variable in SCIPvarGetOrigvarSum()
4524- fixed setting solution value of multi-aggregated var in xml-solution case
4525- fixed bug changing the variable type of an negated variable
4526- fixed numerical troubles in SCIPcreateFiniteSolCopy()
4527- fixed bug in SCIPpermuteProb(): if called before transforming the problem, data structures were not initialized yet
4528- fixed bug in aggregation procedure if two variables were of non-binary type but for one of the variables
4529 SCIPvarIsBinary() returned true
4530- treat activities of pseudo solutions as invalid when containing positive and negative infinity contributions
4531- fixed bug in GMI example: fractionality of slack variable is now computed correctly
4532- fixed LP interface of CPLEX: functions getBInv* return the correct sign of the coefficients.
4533- fixed bug in SCIPpermuteProb(), when called in transformed stage and non-active constraints exist
4536 - use dual feasibility tolerance for comparisons regarding reduced costs
4537 - fixed bug in prop_dualfixing: don't fix variables to infinite values during solving
4538 - fixed sign of the dual multipliers returned by AMPL interfaces for maximization
4540- Objective and Time Limit:
4541 - fixed wrong output of status when an objective limit was imposed but not reached yet
4542 - fixed the rare case that branching was performed even though strong branching found global bound changes leading to
4543 an infeasible/objlimit LP
4544 - fixed bug that objective limit was not reset correctly during SCIPfreeTransform() for maximization problems
4545 - fixed bug that hitting the time limit while solving a pure LP and then continuing the solving process lead to
4546 not solving the LP, but always creating a single child node until maximum depth is reached
4549 - fixed bug leading to an incorrect dual bound when solving probing LPs within a DURINGPRICINGLOOP heuristic
4550 - fixed bug in proximity heuristic which attempted to enter diving mode even at nodes without a constructed LP
4551 - fixed wrong pseudo cost updates during diving heuristic execution after backtracking
4552 - fixed bug in heur_oneopt: avoid bound violations if shift value is negative due to infeasibilities
4553 - fixed bug that reaching a solution limit by beforenode heuristics lead to disregarding the current node if the
4554 optimization process was restarted later
4555 - fixed bug in trysol heuristic not saving the best solution in maximization problems
4558 - fixed bug in presolving of abspower constraints that lead to wrong variable locks
4559 - allow to call SCIPmarkConsPropagate() in INITPRESOLVE stage
4560 - fixed bug in components presolver with handling of dual fixable variables: unboundedness was not detected,
4561 better handle components with single variables by dual fixing propagator
4562 - issues in component solving by presol_components do not lead to stopping the overall process, anymore, the component
4566 - fixed bug with freeing problem: need to reset objective limit
4567 - fixed memory leaks in case of erroneous parsing of constraints, e.g., non-linear constraints
4568 - fixed missing memory allocation for node data in digraphs
4571 - fixed bug in cons_quadratic which leads to wrong min/max activities
4572 - removed wrong break in cons_pseudoboolean
4573 - fixed bug in cons_varbound.c using the wrong constraint side for updating an upper bound
4574 - fixed bug in presolve of cons_nonlinear: wrong constraint upgrades may have been performed due to outdated bound
4575 information in expression graph
4576 - fixed bug in cons_setppc, wrongly aggregating variables if dual-presolving was disabled
4577 - fixed bug in cons_sos1: locks and events were not initialized if constraint was added to transformed problem
4578 - fixed bug in cons_setppc with dual presolving disabled
4579 - corrected copy of disjunction constraints
4582 - allow to read numbers like `42856.` in lp-format
4583 - fixed bug(?) in reader_mps: variables are now written in columns section even of they occur in no constraint
4584 and have an objective coefficient of 0 (otherwise, CPLEX and Gurobi cannot read the file)
4585 - fixed bug with reading `>=1` indicator constraints in LP-files
4586 - fixed bug in reader_lp which created two indicator constraints with the same name to trigger an equality
4587 - fixed bug when reading indicator constraints for linear constraints (equations/ranged rows) from MPS files
4589@section RN310 SCIP 3.1.0
4590*************************
4595- added breadth first search node selection
4596- new node selection rule UCT which balances exploration and exploitation by considering node visits
4597- added possibility to not set a cutoff bound in the LP solver (can be enabled by setting `lp/disablecutoff` to TRUE)
4598- added missing debugging solution check for cliques
4599- added a data pointer to each node of the `SCIP_DIGRAPH`
4600- SCIPgetVarCopy() will now copy the original bounds when called for an original variable
4601- added upgrade of continuous variables to implicit variables for linear equations even if the coefficient is
4603- probing supports implicit binary variables
4604- added scaling to computation of relative interior point in SCIPcomputeLPRelIntPoint()
4607 - added two methods to iterate over a sparse solution (`SCIP_SPARSESOLUTION`), see pub_misc.h
4608 - it is now possible to add an offset for the original problem instance, all original solutions will be initialized with
4609 this value and updated, when the offset is changed
4610 - extended and corrected dual feasibility checks for LP solution (controlled by parameter `lp/checkdualfeas`)
4612- Cuts and Separation:
4613 - the rank of cuts is now stored and taken into account to improve numerical stability
4614 - added possibility to separate a cutpool w.r.t. a given solution (instead of LP-solution)
4617 - new branching rule `cloud branching` that considers several alternative LP optima
4618 - additional vbc output added: branching information is printed earlier and also for nodes which were cut off
4619 - added support for strong branching with domain propagation in full strong and reliability pseudo cost branching
4620 - added strong branching with domain propagation support: in SCIPstartStrongbranch(), support for propagation can
4621 be enabled (uses the probing mode, some overhead compared to standard strong branching), after that
4622 SCIPgetVarStrongbranchWithPropagation() can be used to perform strong branching on a variable with previous domain
4623 propagation; similar to probing, valid bounds for variables are collected
4624 - strong branching with propagation can be enabled in fullstrong and relpscost branching rule
4625 - added possibility to store pricing norms of the LP solver (in addition to basis information) to speed up LP solving
4626 after a backtrack, e.g. in probing or strong branching with domain propagation
4627 - a pricer can now return that no further pricing should be done but rather early branching, even if it added variables
4630 - SoPlex (>= 1.7.0.5) can compute condition number of current basis matrix via LP interface
4631 - LPI files (lpi*.[h|c]) all moved from src/scip to src/lpi
4634 - added propagation method to cons_xor relying on Gaussian elimination, which can also produce feasible solutions
4635 - added first implication detection in cons_linear
4636 - cons_indicator can now try to construct feasible solutions from a cover
4637 - added possibility to forbid upgrading of linear constraints
4638 - new initial constraints are now added to the LP before solving a probing LP
4639 - first implementation of parsing for nonlinear constraints in CIP format
4640 - added upgrade from varbound constraints to set-packing constraints
4641 - added upgrade from bounddisjunction constraints to set-packing/logicor constraints
4642 - cumulative constraint handler adds disjunctive constraints (cumulative with capacity 1) for all jobs which cannot
4643 be processed in parallel
4644 - added new clique extraction algorithm for linear constraints
4645 - the slack variables of indicator constraints can now be scaled
4646 - added redundancy check of sides of ranged row varbound constraint
4647 - added coefficient tightening for ranged row varbound constraint
4648 - XOR constraint handler can add two extended formulations (flow/asymmetric, parameter `addflowextended/addextendedform`)
4649 - added multi-aggregation for binary variables with at most two uplocks and two downlocks, which emerge from set-
4650 partitioning or set-packing constraints
4651 - added upgrade from quadratic constraints to set-packing constraints
4652 - generalized the linking constraint handler
4655 - can now read and write CIP-files with (multi-)aggregated variables
4656 - all readers now take the global parameters `reading/dynamic{conss|cols|rows}` and `reading/initialconss` into account
4657 - added reader_pbm, which writes the constraint-variable incidence matrix in pbm format (possibly scaled to given size)
4658 - reader_osil can now read SOS1 and SOS2 constraints
4659 - reader_lp and reader_mps are now able to write and-constraints in form of their (weak/strict) relaxation
4660 - added reading capability to GAMS reader (if compiling with GAMS=true, requires a GAMS system)
4661 - added capability of writing SOS1/2 constraints to GAMS reader (introduces extra variables and equations)
4664 - new primal heuristics dual value
4665 - new LNS heuristic called `proximity`, which solves a problem in which a local branching constraint replaces the
4666 objective function which in turn is treated as additional constraint
4667 - new LP-based rounding heuristic (heur_randround) whose randomized rounding is biased towards the LP solution value;
4668 the heuristic uses the probing mode of SCIP to generate conflict clauses on the fractional variables
4671 - added new dual presolving for setppc-constraints
4672 - changed dualfix presolver to propagator such that dual fixing can also be applied during repropagation of the root node
4673 - added full-dual presolving step in setppc constraint handler
4674 - dual solution can now be displayed for pure LPs when no presolving was performed
4675 - added clique presolving for xor constraints
4676 - added presolving using pairs of variable bound constraints that use the same variables
4677 - added more presolving to cons_indicator, checking whether indicator/slack variables are aggregated
4678 - added presolve.{c,h} which should be used for all preprocessing mechanisms executed from within SCIP, corresponding to
4679 solve.{c,h} and also for presprocessing methods which can be called from different plugins or from the core to avoid
4681 - return error if variable should be fixed to infinity after presolving (LP-solvers do not handle this consistently)
4682 - in verblevel `SCIP_VERBLEVEL_FULL`, the number of non-zeros will be output for the original and presolved model
4683 - new presolving step for tightening logicor constraints using implication and clique information
4684 - several new presolving steps for linear and knapsack constraints, using gcd information and many more
4687 - added average gap based on primal-dual integral to solution statistics; can be disabled via parameter
4689 - the statistics now include the value of the first LP solved at the root node (without cuts)
4690 - added new statistic which distinguishes between internal nodes and leaves which got processed
4691 - new section `Root Node` in statistics, listing objective value, iterations and solving time for the first LP solved
4692 at the root node as well as final dual bound of the root node and LP iterations for processing the root node
4693 (those where listed in the `Solutions` section before, named `Root Dual Bound` and `Root Iterations`)
4695Performance improvements
4696------------------------
4698- allow multiaggregation of binary variables
4699- shorten conflicts and deriving global boundchanges from conflicts
4700- apply lowerbound provided by pricers already during pricing loop, stop pricing if the lower bound computed by pricing
4701 already exceeds the cutoff bound
4702- improved performance of SCIPcliquelistDel(), SCIPcliquetableAdd(), SCIPcliquetableCleanup()
4705 - strong branching LP solutions are checked for integrality
4706 - improved LP reoptimization for branch-and-price applications
4707 - improved numerical stability checks for LP solution
4708 - faster feasibility check of LP solutions (controlled by parameters `lp/checkprimfeas` and `lp/checkdualfeas`)
4711 - improved methods SCIPlpiGetBInv{Row,Col,ACol} for row representation in SoPlex LP interface
4712 - improved performance of method SCIPsolRetransform() when called during presolving with many aggregations
4713 - minor presolving performance improvements in cons_logicor.c and cons_knapsack.c
4714 - dual fixing presolver was turned into a propagator
4715 - many presolving improvements in constraint handlers
4716 - improved dual-presolving for setppc constraints in special cases
4719 - major improvements in pseudo-boolean constraint handler
4720 - performance improvement in domain propagation by marking constraints for propagation
4721 - added more constraint upgrading possibilities
4722 - improved handling of initial constraints created during solving
4723 - disabled scaling in feasibility check of nonlinear constraint handlers
4724 - conflict consisting of exactly two binary variables will be handled as set-packing constraint instead of an logicor
4725 constraint and the corresponding clique information is globally added
4726 - fasten repropagation for set-packing and -partitioning constraints
4727 - improved merging of and-constraints
4728 - disabled multi-aggregation in linear constraint handler when coefficients differ too much
4729 - improved multi-aggregation in linear constraint handler when only one variable in the aggregation has infinity
4731 - added upgradability for implicit binary variable cases for linear constraints
4733Examples and applications
4734-------------------------
4736- new textbook Gomory mixed integer cuts example
4741- removed all message length parameters in message.c and for printing error messages (not needed anymore)
4743### New and changed callbacks
4745- Domain Propagation:
4746 - added parameter `nmarkedconss` to SCIP_DECL_CONSPROP() callback which gives the number of constraints marked
4747 for propagation (these constraints are listed first in the conss array given as parameter).
4750 - Added parameter `nodeinfeasible` to SCIP_DECL_HEUREXEC() callback which states whether the current subproblem was
4751 already detected to be infeasible. In this case, the current LP solution might not respect local bounds and the
4752 heuristic must not assume that it does.
4755 - Added parameter `stopearly` to callback method SCIP_DECL_PRICERREDCOST(). This boolean pointer should be used by the pricer
4756 to state whether early branching should be performed, even if new variables were added in the current pricing round.
4759 - new possible return value `SCIP_DIDNOTFIND` for SCIP_DECL_BRANCHEXECLP(), SCIP_DECL_BRANCHEXECPS(), and
4760 SCIP_DECL_BRANCHEXECEXT() callbacks to state that the branching rule searched, but did not find a branching.
4762### Deleted and changed API methods
4764- SCIPcalcMIR() takes an additional parameter sidetypes to determine which side of the rows to use
4765 (relevant for ranged rows)
4766- SCIPvarParseOriginal() and SCIPvarParseTransformed() now return the end of the parsed string
4767- SCIPgetConsCopy() now always captures the created constraint
4770 - Added parameter `nfracimplvars` to SCIPgetLPBranchCands()
4771 - SCIPgetLPBranchCands() can be used to retrieve the number of implicit integer variables with fractional LP solution
4772 value via an additional pointer; the corresponding implicit integer variables can be accessed together with their
4773 fractionalities and solution values in the same way as binary and integer variables before; the arrays are sorted such
4774 that binary and integer variables precede the implicit integer variables; the method SCIPbranchcandGetLPCands()
4775 has been modified in the same way
4777- LP and Cutting Planes:
4778 - Added parameter `sidetypes` to SCIPcalcMIR() to specify the specify row side type to be used.
4779 - Added parameter `cutrank` to SCIPcalcMIR() and SCIPcalcStrongCG() which stores the rank of the returned cut;
4780 via SCIProwChgRank() the rank of a cut can be changed (default rank is 0)
4781 - Added parameter `infeasible` to SCIPaddCut() which is a pointer to store whether the cut is infeasible for the
4783 - SCIPgetLPObjval() now returns the LP value of the current (suboptimal) basis if the iteration limit is hit during LP
4784 solving (instead of -infinity); this value is not necessarily a valid dual bound and must not be used as such, but can
4785 be used as an objective estimate, e.g., if strong branching is simulated using the probing mode
4786 - removed parameter `normtype` from function SCIPcomputeLPRelIntPoint()
4789 - Added parameter `lazyconss` to SCIPwriteMIP() to swith writing removable rows as lazy constraints.
4790 - Added parameter `enablepropagation` to SCIPstartStrongbranch(), which can be used to enable strong branching
4791 with domain propagation.
4792 - SCIPstartStrongbranch() has a new parameter `propagate` to enable or disable propagation support for strong branching
4793 - New method SCIPgetVarStrongbranchWithPropagation() which performs strong branching with propagation on a variable.
4794 - Added parameter `endptr` to SCIPparseVar() which stores the final string position after parsing.
4796### New API functions
4798- added SCIPdebugCheckConss() to the debugging mechanism and therefore created a `SCIP_SOL` (in original space) in debug.c
4799- before copying solutions to the original solution candidate storage, infinite solution values can now be removed using SCIPcreateFiniteSolCopy()
4800- SCIPsortLongPtrRealBool(), SCIPsortLongPtrRealRealBool(), SCIPsortLongPtrRealRealIntBool() and corresponding
4801 methods for sorting, insertion and deletion
4802- SCIPstoreSolutionGap() in scip.c, to store the gap when the first and last solution is found
4803- SCIPwriteCliqueGraph() which allows to write a graph with node weights for fractional variables
4806 - SCIPconshdlrIncNCutsFound(), SCIPsepaIncNCutsFound() and SCIPsepaIncNCutsFoundAtNode() to increase the number of found cuts
4807 - SCIPseparateSolCutpool() to separate a cutpool w.r.t. a given solution
4809- Constraint Handlers:
4810 - New method SCIPconshdlrGetStrongBranchPropTime() which returns the time used for domain propagation methods
4811 of the constraint handler during strong branching.
4812 - New method SCIPconsIsMarkedPropagate() which returns whether a constraint is marked for propagation.
4813 - New methods SCIPconsAddUpgradeLocks() and SCIPconsGetNUpgradeLocks() to increase or get the number of upgrade
4814 locks of a constraint.
4815 - New method SCIPgetNCheckConss() which returns the number of checked constraints.
4818 - New methods SCIPsparseSolGetFirstSol() and SCIPsparseSolGetNextSol() to get the first sparse solution
4819 or iterate over the sparse solutions, respectively.
4820 - New methods for the `SCIP_QUEUE` data structure in pub_misc.h to handle a (circular) queue, e.g., SCIPqueueCreate(),
4821 SCIPqueueFree(), SCIPqueueInsert(), SCIPqueueRemove(), SCIPqueueFirst(), SCIPqueueIsEmpty(), SCIPqueueNElems()
4822 - New method SCIPgmlWriteNodeWeight() to write a node section including weight to a .gml graph file.
4823 - New methods for hash tables: SCIPhashtableRemoveAll(), SCIPhashtableGetNElements(), SCIPhashtableGetLoad()
4824 - New methods in pub_misc.h to handle a resource activity, e.g., SCIPactivityCreate(), SCIPactivityFree(),
4825 SCIPactivityGetVar(), SCIPactivityGetDemand() ...
4826 - New methods for digraphs: SCIPdigraphResize() to resize the graph and SCIPdigraphSetNodeDatas() and
4827 SCIPdigraphGetNodeDatas() to set and get the data attached to the nodes.
4829- Domain Propagation:
4830 - New method SCIPpropGetStrongBranchPropTime() which returns the time spent by a domain propagator during strong branching.
4831 - New methods SCIPmarkConsPropagate() and SCIPunmarkConsPropagate() to (un)mark a constraint for propagation.
4833- LP and Cutting Planes:
4834 - New methods SCIPchgRowLhsDive() and SCIPchgRowRhsDive() to change left and right hand side of a row during diving.
4835 - Added parameter `cutoff` to SCIPsolveDiveLP(), SCIPsolveProbingLP(), and SCIPsolveProbingLPWithPricing()
4836 which is a pointer to store whether the diving/probing LP was infeasible or the objective limit was reached.
4837 - SCIPgetFirstLP{Dual/Lower}boundRoot() which return the value of the first LP solved at the root node
4838 - SCIPgetNRootFirstLPIterations() which returns the number of LP iterations for the first LP solved at the root node
4839 - SCIPlpiGetNorms(), SCIPlpiSetNorms() and SCIPlpiFreeNorms() for getting the LP pricing norms from the LP
4840 solver, loading them back into the solver and freeing the data
4841 - New method SCIPgetFirstLPTime() and SCIPgetNRootFirstLPIterations() to return time and iterations for the first LP solve
4842 and SCIPgetFirstLPDualboundRoot() and SCIPgetFirstLPLowerboundRoot() to return the first root LP dual and lower bound.
4843 - New method SCIPprintDualSol() which prints the dual solution for a pure LP (works only with preprocessing disabled).
4844 - New method SCIPisCutApplicable() which returns whether a cut is good enough to be applied.
4847 - the main output routine of message.c (`bufferMessage` now handleMessage) has been rewritten: it now does not need
4848 a copy of the string to be output anymore, which makes the code much simpler (and also faster); it is passed a
4849 function pointer to the output function and uses it to directly output the (buffered) messages
4850 - New generic messagehandler output callback method SCIP_DECL_MESSAGEOUTPUTFUNC().
4851 - Removed parameter `msglength` from callback method SCIP_DECL_ERRORPRINTING().
4852 - New method SCIPmessageVPrintError() to print an error message.
4853 - Removed method SCIPmessagePrintWarningHeader().
4856 - New method SCIPparamGetCharAllowedValues() to get the allowed values for a char parameter.
4857 - New method SCIPgetParam() to get the parameter with a given name.
4860 - SCIPapplyProbingVar() in prop_probing.h
4861 without deteriorating its objective value
4862 - SCIPshrinkDisjunctiveVarSet(), which takes an set of variables with corresponding bounds and boundtypes, and
4863 tries to derive global boundchanges and also to shorten this set of variables by using cliqe, implication and
4864 variable bound information
4865 - SCIPselectVarStrongBranching() to get the variable that fullstrongbranching would select
4866 - New method SCIPvarGetValuehistory() to get the value-based history of a variable.
4869 - New method SCIPdoNotMultaggr() which returns whether multi-aggregation was disabled.
4870 - New method SCIPcreateFiniteSolCopy() to create a copy of a solution with infinite fixings removed.
4871 - New method SCIPadjustImplicitSolVals() which sets implicit integer variables to an integer value in the given
4872 solution without deteriorating its objective value.
4873 - New method SCIPcopyOrig() to copy the original problem. Analoguosly, use SCIPcopyOrigProb(), SCIPcopyOrigVars(),
4874 and SCIPcopyOrigConss() to copy original problem data, variables, or constraints, respectively.
4875 - New method SCIPwriteCliqueGraph() to write the clique graph in GML format into a given file
4876 - New method SCIPaddOrigObjoffset() to add an offset to the objective function.
4877 in original space and updates all orignal solutions correspondingly
4878 - New method SCIPcopyImplicationsCliques() to copy implications and cliques to a copied SCIP instance.
4879 - New method SCIPgetOpenNodesData() which returns all unprocessed nodes.
4880 - Added parameter `endline` to SCIPprintDisplayLine() to switch printing a newline symbol at the end of the line.
4881 - New method SCIPgetNLimSolsFound() returning the number of feasible primal solution respecting the objective limit.
4883### Command line interface
4885- allow dialog option to write clique graph
4886- dual solution values can now be obtained in the interactive shell after solving a pure
4887 LP without presolving
4889### Interfaces to external software
4891- new SoPlex 2.0 interface, can be enabled with `LPS=spx2`
4892- add support for SOS1 and SOS2 constraints to AMPL interface (see `interfaces/check/testset/SOS/sos?a.mod` for example)
4893- added copy of GAMS interface from COIN-OR/GAMSlinks project; GAMS-reader in SCIP can now read model instances from .gms files
4894- beta version of a python interface for the scipoptsuite is now available under interfaces/python
4895- beta version of a Java native interface is now available under `interfaces/jni`
4897### Changed parameters
4899- parameter `branching/scorefunction` has new value `q` for for `q`uotient branching score function
4900- replaced parameter `lp/checkfeas` by two parameters `lp/checkprimfeas` and `lp/checkdualfeas` to decide on primal and dual
4901 feasibility checks individually
4902- removed all local parameters `reading/(READER)/dynamic{conss|cols|rows}` and replaced them by global parameters
4903 `reading/dynamic{conss|cols|rows}`
4904- changed default value of parameter `numerics/dualfeastol` to 1e-7 for safer dual bounds from LP solver
4905- new possible values for parameter `heuristics/shiftandpropagate/sortkey` for sorting variables w.r.t. their norm,
4906 default changed from `u` to `v`, which means sorting downwards by violations
4909 - changed type of parameters `constraints/bivariate/scaling`, `constraints/quadratic/scaling`, `constraints/soc/scaling`
4910 from boolean to character
4911 - changed default for `constraints/{abspower,bivariate,nonlinear,quadratic,soc}/scaling` to off
4912 - changed default max coefficient for big-M constraint to be initial from 1e6 to 1e9
4915 - changed default value of gomory cut separation parameter `separating/gomory/maxrank` from 0 to 3, to take also gomory
4916 cuts that could not be scaled to integral coefficients, with maximal rank 3 into account
4917 - remove parameter `separating/closecuts/relintnormtype`
4921- `branching/checksol` and `branching/heursbsol` to specify whether the strong branching LP solution
4922 should be checked for feasibility and whether a simple rounding heuristic should be run on this solution
4923- `branching/firstsbchild` and `branching/forceall` to specify the first child node to be
4924 investigated during strong branching (`u`p, `d`down, `a`uto) and whether always both children should be solved (only for
4925 strong branching with domain propagation, per default, the second child is not looked at when the first is infeasible)
4926- `conflict/fullshortenconflict` to decide whether we want to stop shortening a conflict set, when no
4927 global bound changes can be found anymore
4928- `conflict/maxvarsdetectimpliedbounds` to decide whether the a valid conflict of what maximal length
4929 will be used to derive global bound changes
4930- `constraints/{linear,knapsack}/detectcutoffbound` and `constraints/{linear,knapsack}/detectlowerbound`
4931 to enable/disable detection of constraint parallel to the objective function that will add an cutoffbound or an
4932 lowerbound respectively and these constraints will be prevented from entering the LP
4933- `constraints/and/upgraderesultant` to upgrade resultants of and constraints from binary to implicit binary variables, default is TRUE
4934- `constraints/abspower/scaling` and `constraints/nonlinear/scaling`
4935- `constraints/indicator/scaleslackvar` for scaling of the slack variable in indicator constraints
4936- `constraints/indicator/trysolfromcover` for trying to construct a feasible solution from a cover
4937- `constraints/linear/checkrelmaxabs` for checking linear constraints with a side of 0.0 relative to
4938- `constraints/linear/detectpartialobjective` to enable/disable the detection of sub-equations of the objective function
4939- `constraints/logicor/strengthen`, should pairwise constraint comparison try to strengthen constraints by removing superflous non-zeros?
4940- `constraints/xor/addextendedform` to add an extended formulation in XOR-constraints
4941- `constraints/xor/addflowextended` to add use the extended flow formulation in XOR-constraints
4942- `heuristics/<heurname>/lplimfac` for LNS heuristics to limit the number of LPs solved in a subproblem
4943 the maximum absolute value in the activity instead of 1.0
4944- `heuristics/shiftandpropagate/fixbinlocks` for fixing binary variables with no locks in one direction to the corresponding bound
4945- `heuristics/shiftandpropagate/collectstats` which decides whether variable statistics are collected
4946- `heuristics/shiftandpropagate/impliscontinuous` to decide whether implicit integer variables are treated as continuous variables
4947- `heuristics/shiftandpropagate/preferbinaries` and `heuristics/shiftandpropagate/stopafterfeasible`,
4948 which decide whether binaries should be shifted first and the shifting should be stopped when no violations are left
4949- `lp/disablecutoff` to toggle usage of LP cutoff bound (0: enabled, 1: disabled, 2: auto = disabled if pricers are used)
4950- `misc/calcintegral` (default TRUE) to trigger calculation of primal-dual integral
4951- `misc/finitesolutionstore` to switch whether infinite fixings should be removed from solutions before
4952 copying them to the original solution store
4953- `misc/permuteconss` and `misc/permutevars` to control whether variables and/or constraints should be permuted, if permutationseed != -1
4954- `presolving/components/feastolfactor` to increase the feasibility tolerance in all sub-SCIPs, when solving a component
4955- `propagating/obbt/conditionlimit` to discard instable LP bases
4956- `reading/(READER)/initialconss` that determines whether model constraints are initial
4957- `reading/cipreader/writefixedvars` for disabling printing of fixed variables in CIP format
4958- `reading/lpreader/aggrlinearization-ands` and `reading/mpsreader/aggrlinearization-ands` to enable/disable
4959 the printing of the weak or strict relaxation of and-constraints in LP and MPS format, respectively
4960- `reading/lpreader/linearize-and-constraints` and `reading/mpsreader/linearize-and-constraints` to
4961 allow and-constraints to be linearized when printing in LP and MPS format, respectively
4962- `separating/feastolfac` to allow dynamic decrease of relaxation feasibility tolerance depending on feasibility to applied cuts,
4963 i.e., allow relaxation solutions to have a primal infeasibility of at most this factor times the infeasibility of applied cuts
4964- `separating/gomory/sidetypebasis` to decide whether the sides of ranged rows should be determined from the basis status
4965- `separating/oddcycle/cutthreshold` to run odd cycle separation if not enough cuts have been found
4966- `separating/zerohalf/delayedcuts` to use the delayed cutpool for the zerohalf separator
4967- `write/allconss` to enable that all constraints are written
4968- `write/genericnamesoffset` when writing a generic problem to define an offset on the variable numbering
4972- New structure to store value-based branching and inference history (see pub_history.h).
4973- new data structure for (circular) queues (`SCIP_QUEUE`)
4974- hash tables will now increase dynamically
4975- Moved LP solver interfaces to subdirectory `src/lpi`.
4980- added McNemar tests and Wilcoxon signed rank tests to cmpres.awk evaluation scripts
4981- added passing MEM option of testgams(cluster) target as workspace option to GAMS jobs
4982- extended test scripts by statistical tests
4989- default flag for ZIMPL is now `auto`, which means that it is built if and only if GMP is available (GMP=true)
4990- fixed make install for older Mac systems where install command does not have option -t
4991- dropped support for Ipopt < 3.10
4996- fixed bug when adding (global) clique, implications or variable bound information in solving stage that lead to
4997 global bound changes which contradict local bounds and therefore need to be stored as pending bound changes
4998- unlinking a solution now copies solution values smaller than SCIPepsilon() avoiding some feasible solution in the
4999 transformed problem to be infeasible in the original problem
5000- fixed bug when flushing the warning buffer when SCIP is closed
5001- fixed bug when a bound change contradicts a local bound and is stored as pending, but the contradicting local
5002 bound becomes global afterwards (--> node where pending bound change is valid can be cut off)
5003- fixed statistics bug: externally given solutions and new solutions found while transforming existing ones
5004 are now listed in line `other solutions` of primal heuristics statistics
5005- fixed bug in random generators SCIPgetRandomInt() and SCIPgetRandomReal() for large intervals
5006- make sure that bound changes of negated original variables are correct
5009 - fixed bug w.r.t. changing the variable branching priority beyond the problem stage
5010 - allow again branching on continuous variables with huge bounds
5013 - fixed bug in sepa_cgmip computeObjWeightSize() w.r.t. equal sized rows
5014 - fixed wrong bound calculation in sepa_rapidlearning
5015 - fixed bug in flowcover separator to exclude unconstrained rows in aggregation
5018 - fixed bug that lead to resolving the LP after diving instead of restoring the buffered solution
5019 - fixed rare bug with conflict analysis and LP/LPI having different states after diving
5020 - fixed several bugs in lpi_grb
5021 - fixed wrong strong branching results in lpi_grb.c and an invalid write
5022 - fixed bug in handling max-function in ampl interface; added support for min-function
5025 - fixed bug in prop_dualfix w.r.t. to fixing of variables to infinity after presolving
5026 - fixed wrong presolving finished status which sometimes occurred when the time limit was hit during presolve
5027 - fixed bug where a limit on presolving rounds was exceeded by 1
5028 - fixed minor bugs in presolving in cons_setppc.c and cons_logicor.c
5029 - fixed minor bug in cons_linear w.r.t. disabled presolving
5032 - fixed bug in genvbounds propagator occurring when objective offset or scale changes after a restart
5033 - fixed bug in genvbounds propagator by replacing non-active variables on right-hand side after presolving
5036 - fixed memory bug in reader_mps
5037 - fixed several minor bugs with handling of memory when writing aggregated variables (reader_lp, reader_mps)
5038 - fixed bug in reader_lp when writing bilinear terms (product sign was missing)
5039 - fixed bug in reading indicator constraints in mps-format
5040 - nonlinear readers now create auxiliary objective variables and constraints always as initial and not removable
5041 in order to avoid unbounded LPs due to loose variables with infinite best bound
5044 - fixed several bugs where variables or constraints were not freed correctly
5045 - do not multi-aggregate variables if the constant would be a huge value in order to avoid numerical troubles
5046 - fixed bug with infinite multi-aggregation constants
5047 - fixed output of aggregated variables in indicator constraints in lp and mps-format
5048 - improved handling of initial constraints: constraints which are initial, but added during the search to an already
5049 treated node are kept and added to the LP at every node where they are active
5050 - fixed bug in cons_superindicator concerning names of upgraded constraints
5051 - fixed bug in cons_indicator with trying to create solution in problem stage
5052 - fixed bug in cons_orbitope with fixing upper right triangle in non-root nodes
5057- new SCIP Optimization Suite homepages
5059@page RN3_0 Release notes for SCIP 3.0
5061@section RN302 SCIP 3.0.2
5062*************************
5067- reading erroneous CIP files can now output some indication of syntax errors
5068- can now run splint on core files
5069- cons_xor now uses the integral variable in propagation
5070- allowed to switch on/off the solution debugging
5072Performance improvements
5073------------------------
5075- improved SCIPlpiAdd{Cols,Rows}() in SoPlex LPi
5077Examples and applications
5078-------------------------
5083### New API functions
5085- SCIPmarkColNotRemovableLocal() and SCIPmarkRowNotRemovableLocal() to forbid removal of an column/row
5086 from the LP in the current node
5087- SCIPmessageVPrintError()
5089### Command line interface
5091- can now output the solutions in the solution pool in the interactive shell
5093### Interfaces to external software
5095- updated Mosek LP interface to compile with Mosek 7
5100- fixed bugs in solution counting
5101- fixed fieldtypes in sorting template
5102- fixed bug concerning the userinterrupt flag, which was not reset
5103- fixed solution collection when counting solutions
5104- fixed bug with storing original solutions
5105- fixed bug with infinite multi-aggregation constants
5106- fixed bug that removing reverse implication did not reset closestvblpcount
5107- fixed bug that duplicate solutions stopped copying of solutions to original solution candidate store
5108- forbid branching on variables with huge bounds; such huge values cannot be enumerated with fixed precision
5109 floating point arithmetics
5110- fixed bug that Ipopt's error message was not fully shown due to exiting before the message handler buffer was emptied
5111- unlinking a solution now copies solution values smaller than SCIPepsilon() avoiding some feasible solution in the
5112 transformed problem to be infeasible in the original problem
5113- allow to add columns (rows) with nonzero indices beyond current number of rows (columns) in SoPlex LPi
5114- updated get.ASL script to cope with broken ftp access to netlib server
5117 - fixed bugs with freeing C++ object data for problem and variables
5118 - fixed memory leak in lp.c (probably never occurred so far since array was not used)
5119 - fixed bug in sepa_zerohalf.c where the maxcuts(root) parameters led to an invalid memory allocation call
5122 - fixed assert in solve.c with branched status and LP reached the objective limit
5123 - fixed bug in heur_oneopt.c and heur_clique.c which was caused by side-effects when calling SCIPconstructLP(); when
5124 adding new variables in this method (e.g. adding new variables needed for a relaxation), this changes the variables
5126 - fixed problem that diving did not save status for infeasible LPs
5127 - fixed bug in SCIPlpComputeRelIntPoint() with wrong iteration limit and with wrong recompution
5128 - fixed bug that old LP size was not updated for deadend if no LP was solved
5131 - fixed issues with ungraceful termination when encountering unsupported expression operands in AMPL interface
5132 - fixed bug in backward propagation of linear expressions in expression graph
5135 - fixed potential performance issue with tree depth always assumed to be zero when propagating in probing mode
5136 - fixed bug in prop_vbound w.r.t. creation of variables during the search
5137 - fixed several bugs in propagation of cons_xor: need to take integral variables into account
5138 - fixed bug in cons_abspower.c handling infinity values in propagation
5139 - fixed bug in cons_and.c when a constraint was not correctly propagated which led to wrong dual-presolve reductions
5140 - fixed bug in cons_abspower: wrong infinity check when propagating bounds
5143 - fixed bug that the number aggregated variables were not counted in presol_inttobinary.c
5144 - fixed bug in presol_domcol: locks are now checked to see whether rounding was forbidden for a variable
5147 - fixed bug in reader_gms.c w.r.t. writing nonlinear expressions with polynomials with constants
5148 - fixed bugs in parsing bounds from CIP-files, in reader_gms and AMPL interface
5149 - fixed bug when reading a mps formated file with a missing bound in the bound section
5152 - fixed bug in cons_bounddisjunction with satisfied literal of multi-aggregated variable
5153 - fixed bug in upgrade method of cons_soc
5154 - fixed issue with negated variables in cons_xor.c
5155 - fixed several asserts in cons_xor presolving
5156 - fixed bug in cons_xor.c calling method on null pointer row
5157 - fixed bug using a too hard comparison on the objective-infeasible-decision in constraint enforcement
5158 - fixed possible cycling in enforcement of nonlinear constraints due to too early removal of newly added cuts from LP
5159 - fixed bug wrongly removing constraints locally while counting
5160 - fixed bugs in cons_bivariate.c when the nonlinear function is not differentiable on the boundary of the domain
5161 - fixed bug in cons_indicator.c:SCIPmakeIndicatorFeasible() with handling fixed variables
5162 - fixed bug in cons_integral: check integrality of implicit integer variables when a solution is checked for feasibility
5163 - fixed bug in Undercover with `pseudo-`quadratic constraints
5164 - fixed bug with quadratic constraints not being upgraded
5165 - fixed bug in intervalarith.c: bivariate quad. equations may have been solved wrongly if second variable is unbounded
5168 - fixed bug in sepa_zerohalf.c not copying the displays to the subscip, but still changing a display parameter there
5169 - fixed iteration limit determination in sepa_closecuts
5170 - fixed bug in sepa_closecuts: need to make sure that variable values of separation point satisfy bounds
5171 - fixed bugs in sepa_oddcylce: number of arcs have to be adjusted, handle implicit binary variables,
5172 fixed bug in heuristic separation method, fixed asserts
5173 - fixed wrong bound calculation in sepa_rapidlearning
5175@section RN301 SCIP 3.0.1
5176*************************
5181- added delayed cutpool which only gets separated if the sepastore is empty after a separation round
5182- sepa_cgmip can now take the objective row into account
5183- added possibility to run clang compiler
5184- statistics now include output on number of solutions that respect objective limit
5186Performance improvements
5187------------------------
5189- also copying active tight cuts from the delayed cut pool when calling SCIPcopyCuts()
5190- sort genvbounds only when root node is finished; apply more often
5192Examples and applications
5193-------------------------
5198- when using an objective limit, heuristic characters are not displayed any longer for worse solutions
5200### Deleted and changed API methods
5202- fixed spelling in the method name SCIPgmlWriteClosing()
5204### New API functions
5206- SCIPgetNLimSolsFound() to get number of solutions that respect the objective limit
5211- fixed issue with applying the effective root depth during the search
5212- fixed bug concerning usage of dualbound and lowerbound
5213- fixed bug trying to color probing nodes, which are not added to the vbc output anymore
5214- fixed bug in sorting template
5215- fixed bug leading to removing a ranged row parallel to the objective function, although one of the sides was still needed
5216- fixed a bug correcting the binvarssorted flag in cons_linear.c
5217- fixed bug in cons_varbound.c not resolving multi-aggregated variables
5218- relaxed assert in SCIPvarCh{Lb,Ub}{Global,Local} that new bound must be tighter to feastol
5219- fixed contra-intuitive behavior when using SCIP with objective limits and solution limit at the same time;
5220 SCIP now only stops when sufficiently many solutions better than the objective limit have been found
5221- fixed bug when adding binary implications with non-vartype binary variables
5222- fixed bug adding binary implications on binary variables with type != `SCIP_VARTYPE_BINARY`
5223- fixed bug concerning different tolerances for reached objective limit in case of pricing with fastmip
5226 - fixed bug which disabled iteration limit in SCIPlpSolveAndEval()
5227 - ensure consistency of LP bounds during OBBT diving, i.e., that lower <= upper holds exactly
5228 - set lpsolstat to `SCIP_LPSOLSTAT_NOTSOLVED` in SCIPchg{Lp,Dual}feastol()
5229 - use tighter dual feasibility tolerance for LPs solved during optimization-based bound tightening
5230 - fixed bug with unflushed LP arising from global bound changes in strong branching
5233 - fixed issue with deleting varbound constraints in case the bound change was not applied
5234 - fixed bugs in parsing dis-/conjunctive constraints
5235 - fixed bug with handling of empty logicor and bounddisjunction constraints
5236 - fixed issue in cumulative constraint and separation
5237 - fixed bug when sorting knapsack constraints with the same weights
5238 - fixed bug resulting in trying to delete an upgraded linear constraint a second time in exitpre callback
5239 - fixed minor bug in conjunctive constraint handler printing wrong constraint
5240 - fixed bug in disjunctive constraint handler when enforcing a constraint
5241 - fixed behaviour change of indicator constraint handler when solving another instance after solving one using the
5243 - fixed several issues in cumulative constraint handler
5244 - fixed bug in cumulative constraint handler w.r.t. getting active variables
5245 - fixed bug in cumulative constraint handler concerning conflict analysis
5247- LPI and Interfaces:
5248 - fixed bug in CppAD in connection with abspower constraints
5249 - fixed bug in CppAD when using signpower functions with expression pointers that do not fit into an unsigned int
5250 - better handling of generalized (Lagrangian) variable bounds that are not in the LPI
5251 - fixed wrong basis rstat values in CPLEX LPI
5252 - fixed bug with LP not being flushed after bound changes on columns that are not in the LPI
5253 - methods SCIPlpiIs{PrimalFeasible,DualFeasible,DualUnbounded}() in SoPlex LPi now check that the LP is not perturbed,
5254 which may happen when stopping due to iteration or time limit
5255 - fixed inconsistencies between methods SCIPlpiIs{PrimalFeasible,DualFeasible,Optimal,...} in SoPlex LPi
5258 - fixed bug when adding linear constraints with non active variables in solving process, during propagation this
5259 resulted in changing the row, which is not possible for unmodifiable constraints/locked rows
5260 - fixed small issue in pseudo objective propagator w.r.t. propagating the lower bound globally
5261 - fixed bug in cons_orbitope: in rare cases one cannot repropagate
5262 - fixed bug of wrong result code in propagation in prop_genvbound.c
5265 - fixed bug in copying nonlinear constraints during presolve (resulted
5266 in wrongly declaring instances as infeasible when using component presolve)
5267 - fixed bug in copying nonlinear constraints during presolve (nonlinear part was not copied)
5270 - fixed wrong solving status (OPTIMAL) in case an unbounded solution was provided or found by heuristic before presolve
5271 - fixed bug in heur_subnlp running with tightened tolerances: sumepsilon must be tightened like feastol and epsilon
5272 - fixed bug in nlp diving heuristic for fractional variables with values slightly outside of their domain
5275 - fixed several numeric issues
5276 - fixed numerical bug in conflict.c relaxing bounds while keeping an infeasibility proof
5277 - fixed feasibility decision bug when replacing inactive variables by their active counterparts, which might change the
5278 redundancy status of a bounddisjunction constraint due to numerics
5279 - fixed numerical bug adding a relaxed bound for conflict analysis in cons_varbound
5280 - fixed numerical bug in conflict analysis of genvbounds propagator
5282@section RN300 SCIP 3.0.0
5283*************************
5288- SCIPcomputeLPRelIntPoint() with normtype=`s` now uses homogenized LP for computing rel.int. point too and allow to
5289 set relaxrows = FALSE
5290- new column showing the pseudo objective value
5291- digraph structure added to misc.c and pub_misc.h that can be used to handle directed graphs, compute undirected
5292 components in the graph and sort these components (almost) topologically
5293- SCIP does now print an info message when the root LP could not be solved or is unbounded
5294- added counter and clock for SCIPcopy() calls
5295- correct initialization of steepest edge weights with SoPlex 1.6.0.4
5296- parameters can now be fixed, which means that their value cannot be changed unless they are unfixed, first;
5297 the fixing status of a parameter is copied to sub-SCIPs, which allows to ensure that certain parameters
5298 are also not changed when, e.g., heuristics change emphasis settings or also specific parameters
5299- automatic transfer of original solutions (e.g., provided by the user, from solution pool, after restart, from heuristic
5300 adding original solution during solve) to the transformed space (might fail due to, e.g., dual fixings)
5301- added possibility to use GUBs for lifting knapsack cuts (disabled)
5302- added pre- and post-conditions in doxygen documentation for all methods of scip.{c,h}
5303- added zeroobj heuristic that solves a copy of the problem without an objective function and with quite strict limits
5304 on the number of nodes and LP iterations
5305- complete reworking of the vbounds propagator: it now takes into account variable bounds, cliques and implications,
5306 stores bounds of variables which were changed and performs a forward propagation from these bounds, i.e., tries to
5307 derive new bounds for other variables; during propagation, bound changes are propagated in an (almost) topological order
5310 - full version of cumulative constraint handler
5311 - new constraint handler `superindicator` for indicator constraints with slack constraints of arbitrary type
5312 - implemented first clique lifting procedure in cons_setppc.c (by default is off)
5313 - the conjunction and disjunction constraint handlers are now able to parse their CIP output format
5316 - better handling of memory limits, in particular for large problems
5317 - estimate memory consumption for sub-SCIP and do not copy them if close to memory limit
5320 - time for initpre and exitpre methods is now also measured in presolving time
5321 - added dual presolving for and-constraints difficult instances (no guarantees)
5322 - oneopt can now be called before presolving
5323 - added a presolving step in the disjunctive constraint handler, removing disjunction, where a sub-constraint was
5324 deleted, which means this sub-constraint is redundant, which again means it is always TRUE or will be enforced by
5326 - added new presolver convertinttobin, which converts bounded integer variables to their binary representation, e.g.
5327 for integer variable 0 <= x <= 10 the binary variables y0, y1, y2 and y3 are created, such that
5328 1 y0 + 2 y1 + 4 y2 + 8 y3 <= 10 and x = 1 y0 + 2 y1 + 4 y2 + 8 y3
5329 - added new presolver gateextraction, which tries to find and-gates/constraints which are linearized
5330 e.g. (x + y + z >= 1, x + y <= 1 and x + z <= 1 => x == AND(~y,~z)), in special cases it also detects set-partitioning
5331 constraints e.g. (x + y + z >= 1, x + y <= 1, x + z <= 1 and y + z <= 1 => x + y + z == 1));
5332 gate-extractor is also able to detect logicor constraints and set-packing/-partitioning constraints with the same
5333 variables, to upgrade these both constraints to a set-partitioning constraint
5334 - added new presolver components, that searches for independent components in the problem structure and solves
5335 these components as sub-SCIPs when they are small enough (per default <= 20 discrete variables, nodelimit of 10000)
5336 - added new presolver domcol that looks for dominated columns in a MIP and tries to fix them
5339 - CNF reader now creates feasibility instances per default, usage of an objective has to be set by a parameter
5340 - added reader for MI(NL)Ps in OSiL (Optimization Services Instance Language) format
5343 - new statistics and new statistic output messages
5344 - number of presolving calls of plugins is counted and displayed in the statistics,
5345 can be accessed via SCIPpresolGetNCalls() and SCIP{prop/conshdlr}getNPresolCalls()
5346 - the statistics shows for a branching rule the number of calls for LP, extern and pseudo candidates
5347 - new switch `SCIP_STATISTIC` and new macros SCIPstatisticMessage(), SCIPstatisticPrintf() and SCIPstatistic() to output
5348 statistic and execute code lines which are only needed therefor. Works as `SCIP_DEBUG` and SCIPdebugXyz()
5349 - added statistics on the number of cuts/rows that have actually been applied to the lp for each constraint handler and separator;
5350 use SCIPcreate(Empty)RowCons() and SCIPcreate(Empty)RowSepa() to support the statistics.
5353 - new propagators obbt and genvbounds for MINLP
5354 - new NLPI parameter `SCIP_NLPPAR_FASTFAIL` to enable convergence checks in NLP solver to stop early on seemingly
5355 - added nlpdiving heuristic that comprises several diving heuristics using an NLP relaxation
5357Performance improvements
5358------------------------
5360- improved scaling by choosing the smallest scaler
5361- if first root lp is solved and the optimality is rejected by SCIP, there won't be an unnecessary solving of the lp
5363- several performance improvements for Pseudo-Boolean optimization, pseudo objective propagator
5364- streamlined initlp functions in cons_indicator, cons_sos1, cons_sos2 (add rows only if needed)
5365- improved time used for adding implications
5366- speed up in SCIPboolarrayExtend() in misc.c replacing a for loop with BMSmoveMemoryArray() call
5367- speed up in var.c changing some recursive calls into iterative calls and reducing the number of VARFIX event that are
5368 thrown for fixation, aggregation or multi-aggregations
5369- revised reduced cost propagator
5370- increased performance in SCIPcliqueAddVar(), adding a variable to a clique
5371- tighten primal and dual feasibility tolerances independently if they are not reached in LP solving
5374 - if probing reached the end of all variables it will restart the probing cycle correctly
5375 - improved probing by ordering the variables differently and applying the one-branch before the zero-branch
5378 - improved scaling of linear constraints, linear constraints with integral variables will now be scale with
5379 1e+06/MAX(maximal absolute coefficient, 1.0) instead of 1e+03/MAX(maximal absolute coefficient, 1.0);
5380 if all coefficients are in absolute value equal they will be scaled by that
5381 - added clique presolving for and-constraints, which checks if two operands or one operand and the resultant are in a
5382 clique and then fixes the resultant to 0 and in the former case we can delete the and-constraint too
5383 - speed up in linear constraint handler replacing aggregated variables
5384 - when all nonlinearities have been fixed and the number of nonfixed variables is 1 in cons_nonlinear/cons_quadratic/
5385 cons_bivariate, handle it by a bound change instead of adding a linear constraint
5388 - automatically turn off separation in sepa_oddcycle if it was too unsuccessful within the last calls
5389 - use faster Dijkstra variants in sepa_oddcycle
5390 - improved tcliquegraphAddImplicsVars() in sepa_clique.c to faster add possible variables
5391 - changed emphasis settings: knapsack disaggregation is now allowed in fast presolving, CG-MIP separator disabled in
5392 aggressive separation
5395 - improved lp-, mps-, opb-reading time
5396 - speed up mps reader asking parameters only once
5399 - added parameters mincoveredrel and mincoveredabs to heur_undercover to only run if problem is sufficiently nonlinear
5400 - improved intdiving heuristic by activating backtracking to a different fixing value
5401 - heur_undercover treats indicator constraints as nonlinear and fixes the binary variable for linearization
5403Examples and applications
5404-------------------------
5406- new examples for scheduling and usage of the callable library with nonlinear problems
5407- the error messages are not handled via the message handler anymore; per default the error message a written to stderr
5412- introduced basic inclusion and creation methods to simplify usage of the SCIP library
5413- allowed to start diving mode even if LP is not flushed, not solved, or not solved to optimality
5414- changed the message handler system within SCIP heavily such that it is thread save
5415- the resolve propagation methods for the constraint handler and propagator getting a new parameter called relaxedbd;
5416 explaining/resolving this relaxed bound is sufficient
5417- default integer comparer SCIPsortCompInt() (see pub_misc.h)
5420 - SoPlex LPI supports setting of `SCIP_LPPAR_DUALFEASTOL` when using SoPlex version 1.6.0.5 and higher.
5423 - Forbid problem modifications in `SCIP_STAGE_{INIT,EXIT}PRESOLVE` (see pre-conditions for corresponding methods in scip.h).
5426 - New macro SCIPdebugPrintCons() to print constraint only if `SCIP_DEBUG` flag is set.
5427 - all objscip *.h file now use the default SCIP interface macros (this should avoid errors when changing the interface)
5429### New and changed callbacks
5431- Constraint Handler:
5432 - Added a propagation timing parameter `proptiming` to SCIP_DECL_CONSPROP(), giving the current timing at which
5433 this method is called (also to the corresponding c++ wrapper classes).
5434 - New optional callback methods in constraint handlers: `SCIP_DECL_CONSGETVARS` and `SCIP_DECL_CONSGETNVARS`.
5435 These callbacks, if implemented, should return an array of all variables and the number of all variables used
5436 by the given constraint, respectively. (This method might, e.g., be called by a presolver)
5438- NLP Solver Interface:
5439 - New NLPI callback SCIP_DECL_NLPISETMESSAGEHDLR() to set message handler in NLP solver interfaces.
5442 - Added a propagation timing parameter `proptiming` to SCIP_DECL_PROPEXEC(), giving the current timing at which this method is
5443 called (also to the corresponding c++ wrapper classes).
5446 - added `basic` inclusion methods which have only fundamental data of the plug-ins as arguments; added setter functions
5447 for all non-fundamental callbacks of the plug-ins; the plug-in types with basic inclusion functions are:
5448 readers, constraint handlers, conflict handlers, presolvers, propagators, heuristics, separators, relaxation handlers,
5449 branching rules, node selectors and pricers; these methods should make the usage easier, sparing out optional callbacks and
5450 parameters: e.g., SCIPincludeConshdlrBasic();
5451 - To extend the basic functionalities, there are setter method to add
5452 optional callbacks. For example SCIPsetConshdlrParse(), SCIPsetPropCopy() or SCIPsetHeurInitsol().
5454- Constraint Handlers:
5455 - Added basic creation methods for all constraints types, e.g., SCIPcreateConsBasicLinear(); these methods should make the usage easier,
5456 sparing out optional callbacks and parameters.
5458### Deleted and changed API methods
5460- SCIPcomputeCoverUndercover() now has an additional parameter coverbd
5461- tcliqueMaxClique has an additional parameter to store the number of used branch-and-bound nodes
5462- the code in `src/dijkstra` and `src/xml` has been changed to (increasingly) conform to the SCIP coding style;
5463 all function (and variable) names have been changed (do not contain `_` anymore).
5464- renamed SCIPstairmap*Core() to SCIPstairmap*Stair()
5467 - Added parameter `relaxedbds` to conflict handler callback method SCIP_DECL_CONFLICTEXEC(). This array contains
5468 bounds which are sufficient to create a valid conflict
5470- Constraint Handler:
5471 - Added a parameter `restart` to the SCIP_DECL_CONSEXITSOL() callback method, indicating whether this call was
5472 triggered by a restart.
5473 - Added a parameter `relaxedbd` to SCIP_DECL_CONSRESPROP() callback method. If explaining a given bound change
5474 (index), it is sufficient to explain the reason for reaching the `relaxedbd` value, see above
5475 - Removed parameters `isunbounded`, `isinfeasible` and `result` from SCIP_DECL_CONSINITPRE() and SCIP_DECL_CONSEXITPRE()
5476 callback methods. It is not allowed to determine unboundedness or infeasibility in these callbacks, anymore.
5477 - added a `SCIP_CONS*` parameter to SCIPcreateConsDisjunction() which can represent the linear relaxation of the whole
5478 disjunction constraint as a conjunction constraint, or `NULL`
5479 - remove problematic function cons_indicator:SCIPsetSlackVarIndicator()
5480 - Renamed SCIPgetCountedSparseSolutions() to SCIPgetCountedSparseSols() in cons_countsols.{c,h}.
5483 - Changed the counting system within SCIP heavily. New method for `SCIP_SPARSESOL` usage, SCIPsparseSolCreate(),
5484 SCIPsparseSolFree(), SCIPsparseSolGetVars(), SCIPsparseSolGetNVars(), SCIPsparseSolGetLbs(), SCIPsparseSolGetUbs()
5485 in (pub_)misc.{c,h}.
5487- Cuts and Separation:
5488 - removed `targetscip` parameter from SCIPconvertCutsToConss(), now this function can only convert cuts on one instance,
5489 otherwise use SCIPcopyCuts()
5490 - added `ncutsadded` parameter to SCIPcopyCuts() to be able to store the number of copied/converted cuts
5491 - New functions SCIPcreateEmptyRowCons(), SCIPcreateEmptyRowSepa(), SCIPcreateRowCons(), and SCIPcreateRowSepa() that allow
5492 to set the originating constraint handler or separator of a row respectively; this is, for instance, needed for statistics
5493 on the number of applied cuts. If rows are created outside a constraint handler or separator use SCIPcreateRowUnspec() and
5494 SCIPcreateEmptyRowUnspec(). The use of SCIPcreateEmptyRow() and SCIPcreateRow() is deprecated.
5495 - New functions SCIProwGetOrigintype(), SCIProwGetOriginCons(), and SCIProwGetOriginSepa() to obtain the originator
5499 - new parameter numerics/lpfeastol for primal feasibility tolerance used in LP solver
5500 - SCIPcomputeLPRelIntPoint() takes two new arguments giving a time and iteration limit
5501 - SCIPcolGetStrongbranchLPAge(), SCIPgetVarStrongbranchLPAge(), SCIPgetNLPs(), SCIPgetNPrimalLPs(), SCIPgetNDualLPs(),
5502 SCIPgetNBarrierLPs(), SCIPgetNResolveLPs(), SCIPgetNPrimalResolveLPs(), SCIPgetNDualResolveLPs(), SCIPgetNNodeLPs(),
5503 SCIPgetNNodeInitLPs(), SCIPgetNDivingLPs(), SCIPgetNStrongbranchs(), SCIPgetNRootStrongbranchs() now return a longint
5504 instead of an integer
5506- Message Handler and Printing:
5507 - New callback method SCIP_DECL_MESSAGEHDLRFREE() which is called when the message handler is freed.
5508 - The old callback method SCIP_DECL_MESSAGEERROR() was replaced by the callback method SCIP_DECL_ERRORPRINTING().
5509 - the follwing methods additionally need the SCIP pointer as parameter to make the output thread save:
5510 SCIPprintVersion(), SCIPsetMessagehdlr(), SCIPgetMessagehdlr() and SCIPwarningMessage()
5511 - the error printing method can be replaced using the method SCIPmessageSetErrorPrinting(); the default error message
5512 printing can be recoverd via SCIPmessageSetErrorPrintingDefault() (see pub_message.h)
5513 - Changed the message handler system within SCIP heavily such that it is thread-safe. SCIPcreateMessagehdlr() in
5514 scip.{c,h} was replaced by SCIPmessagehdlrCreate() in pub_message.h/message.c with a changed parameter list;
5515 see pub_message.h and type_message.h.
5516 - removed method SCIPcreateMesshdlr(), please use SCIPmessagehdlrCreate() (see pub_message.c)
5517 - removed method SCIPfreeMesshdlr(), please use SCIPmessagehdlrRelease() (see pub_message.c)
5518 - Error messages (SCIPerrorMessage()) are not handled via the message handler anymore; per default the error
5519 message is written to stderr.
5520 - the following methods need an additional message handler: SCIPdispLongint(), SCIPdispInt(), SCIPdispTime(), all message
5521 handler methods (see pub_message.h), SCIPhashtablePrintStatistics(), SCIPhashmapPrintStatistics(), SCIPlpiCreate()
5522 - SCIPprintCons() does not print termination symbol `;\n` anymore; if wanted, use SCIPinfoMessage() to print `;\n` manually
5523 - remove SCIPcolPrint() and SCIProwPrint(), please use SCIPprintCol() SCIPprintRow() see scip.h
5524 - method SCIPprintError() does not need the file stream anymore. The error is written via the error message callback.
5526- Nonlinear expressions, relaxation, and solver interface:
5527 - Method SCIPexprtreeRemoveFixedVars() is not public anymore.
5528 - Renamed SCIPmarkNonlinearitiesPresent() to SCIPenableNLP()
5529 - Renamed SCIPhasNonlinearitiesPresent() to SCIPisNLPEnabled().
5530 - removed SCIPmarkContinuousNonlinearitiesPresent(),
5531 renamed SCIPhasContinuousNonlinearitiesPresent() to SCIPhasNLPContinuousNonlinearity() and allow call only during
5532 initsolve and solve,
5535 - Replaced SCIPparamSet*() by SCIPchg*Param()
5536 + replaced SCIPparamSetBool() by SCIPchgBoolParam()
5537 + replaced SCIPparamSetInt() by SCIPchgIntParam()
5538 + replaced SCIPparamSetLongint() by SCIPchgLongintParam()
5539 + replaced SCIPparamSetReal() by SCIPchgRealParam()
5540 + replaced SCIPparamSetChar() by SCIPchgCharParam()
5541 + replaced SCIPparamSetString() by SCIPchgStringParam()
5544 - Removed parameters `isunbounded`, `isinfeasible` and `result` from SCIP_DECL_PRESOLINITPRE() and
5545 SCIP_DECL_PRESOLSEXITPRE(). It is not allowed to determine unboundedness or infeasibility in these callbacks, anymore.
5548 - changed parameters of function SCIPpropagateCutoffboundVar() in prop_pseudoobj.{c,h}
5549 - Added a parameter `restart` to SCIP_DECL_PROPEXITSOL() callback method, indicating whether this call was triggered
5551 - Added a parameter `relaxedbd` to SCIP_DECL_PROPRESPROP() callback method. If explaining a given bound change
5552 (index), it is sufficient to explain the reason for reaching the `relaxedbd` value.
5553 - Removed parameters `isunbounded`, `isinfeasible` and `result` from SCIP_DECL_PROPINITPRE() and
5554 SCIP_DECL_PROPEXITPRE() callback methods. It is not allowed to determined unboundedness or infeasibility in
5555 these callbacks, anymore.
5558 - The methods SCIPsortedvecInsert*() have an additional parameter which can be used to receive the position where
5559 the new element was inserted, if this is not of interest a `NULL` pointer can be given
5560 - new parameter in SCIPcopyPlugins() to indicate whether the message handler from the source SCIP should be passed to the
5561 target SCIP (only the pointer is copied and the usage counter of the message handler is increased)
5562 - New parameter in SCIPcopy() to indicate whether the message handler from the source SCIP
5563 should be passed to the target SCIP (only the pointer is copied and the usage counter of the message handler is
5564 increased). In multi theaded enviroment this parameter needs to be set to FALSE.
5567 - rename SCIPvarGetBestBound() to SCIPvarGetBestBoundLocal()
5568 - rename SCIPvarGetWorstBound() to SCIPvarGetWorstBoundLocal()
5569 - Method SCIPvarGetProbvarSum() is not public anymore, use SCIPgetProbvarSum() instead.
5570 - Replaced method SCIPvarGetRootRedcost() by SCIPvarGetBestRootRedcost().
5572### New API functions
5574- setup timer to all plugins and therefore SCIP<plugin-type>GetSetupTime() methods in all pub_plugin-type.h to ask
5575 for this time (, e.g. SCIPeventhdlrGetSetupTime() in pub_event.h)
5576- new GML(Graph Modeling Language) methods SCIPgmlWriteOpening(), SCIPgmlWriteCosing(), SCIPgmlWriteArc(), SCIPgmlWriteEdge(),
5577 SCIPgmlWriteNode() that write to a given GML file
5578- new LPI method SCIPlpiGetObjsen() to query objective sense
5579- SCIPpermuteIntArray() in pub_misc.h and misc.c for permuting an integer array
5580- SCIPcalcBinomCoef() in pub_misc.h and misc.c which calculates a binomial coefficient up to 33 over 16
5581- SCIPheurPassSolAddSol() in heur_trysol.c; solution which are passed via this method are just without any feasibility check
5582- SCIPgetGlobalPseudoObjval() which returns the global pseudo objective value which is all variables
5583 set to their best (w.r.t. the objective function) global bound
5584- SCIPhashGetKeyStandard() which returns the element itself as the key, SCIPhashKeyEqPtr(),
5585 SCIPhashKeyValPtr() which do the hash-comparison/-conversion on a pointer in pub_misc.h
5586- SCIPhashtableClear() which removes all elements of a hash table
5587- SCIPisUpdateUnreliable() to check whether an iteratively updated value should be recomputed from scratch
5588 (e.g., for activities; uses new parameter `misc/num_recompfac`)
5589- SCIPisHugeValue() to check whether a value is huge and should be handled separately from other values
5590 (e.g., in activity computations) and SCIPgetHugeValue() to get the smallest value counting as huge
5591- SCIPfixParam() and SCIPunfixParam() to fix and unfix a parameter, respectively;
5592 the fixing status of a parameter can be requested by SCIPparamIsFixed();
5593- SCIPsetBasePointClosecuts() to set the base point for close cut separation
5594- SCIPchgCutoffboundDive() to change the cutoffbound in diving mode
5595- SCIPupdateCutoffbound() which can be used to pass a cutoff bound
5598 - SCIPpropIsPresolDelayed() which return if a propagator is delay during presolving
5599 - Added method SCIPisPresolveFinished() which returns whether the presolving process would be stopped after the
5600 current presolving round, given no further reductions will be found, can be used to ensure that a presolver is called very late
5603 - added forgotten implementation of SCIPfreeMemorySize(), SCIPfreeMemorySizeNull() in scip.h and BMSfreeMemorySize(),
5604 BMSfreeMemorySizeNull() in memory.h
5605 - SCIPmemccpy() in pub_misc.h and misc.c which copies either a specified number of charcters of a source
5606 string to a destination string or until it hits a stoping character
5607 - BMSmoveMemory(), BMSmoveMemoryArray(), BMSmoveMemorySize() and corresponding BMSmoveMemory_call() in
5608 memory.{h,c} too move memory elements
5611 - SCIPisConflictAnalysisApplicable() which return FALSE is the conflict will not runs; can be used
5612 to avoid unnecessary initialization of the conflict analysis
5613 - SCIPaddConflictRelaxedLb(), SCIPaddConflictRelaxedUb() and SCIPaddConflictRelaxedBd(); these methods
5614 can be used to give for a bound change which is part of an explanation a relaxed bound; this means the relaxed bound
5615 is already efficient to be part of a valid explanation
5616 - SCIPisConflictVarUsed() returns TRUE if the given bound change is already part of the conflict set;
5617 that is the bound change is redundant;
5618 - SCIPgetConflictVarLb() and SCIPgetConflictVarUb() returning the lower/upper bound of the given
5619 variable within the current active conflict set
5622 - SCIPvarsGetProbvar() in pub_var.h and var.c, which returns for a given array of variables the active, fixed
5623 or multiaggregated representation
5624 - SCIPgetActiveVars() in scip.{h,c}, which returns for a given array of variables the active counterparts
5625 - SCIPgetNObjVars() which returns the number of variables which have a non-zero objective coefficient
5626 - SCIPenableVarHistory() and SCIPdisableVarHistory() which can be used to turn off and on the collection
5627 of variables statistics which is used for example for branching
5628 - SCIPbranchVarHole() which branches a variable w.r.t. a given domain hole
5629 - SCIPvarGetAggregatedObj() which computes for a (not active) variable the corresponding objective value
5630 - SCIPsolIsOriginal() that returns whether a solution is defined on the original variables
5631 - SCIPgetVarImplRedcost() which returns the implied reduced costs
5632 - SCIPvarGetBestRootSol(), SCIPvarGetBestRootRedcost(), SCIPvarGetBestRootLPObjval() which return the best
5633 combination for a variable w.r.t. root solution value, root LP objective value and root reduced cost
5634 - SCIPhaveVarsCommonClique() in scip.{h,c}, to check for common clique information on two given variables
5635 - added basic creation methods SCIPcreateVarBasic() and SCIPcreateProbBasic() and setter functions for
5636 non-fundamental callbacks of variables and problems.
5637 - added new methods SCIPvarGetBestBoundGlobal() and SCIPvarGetWorstBoundGlobal().
5639- Constraint Handler:
5640 - added public wrapper functions for calling constraint handler callback methods for a single constraint:
5641 SCIPactiveCons(), SCIPdeactiveCons(), SCIPinitlpCons(), SCIPsepalpCons(), SCIPsepasolCons(), SCIPpropCons(),
5642 SCIPrespropCons(), SCIPenfopsCons(), SCIPenfolpCons()
5643 - added basic creation methods for all constraint handlers
5644 - SCIPchgCapacityKnapsack() which can be used to change the capacity of a knapsack constraint
5645 - SCIPconsIsAdded() which returns whether a constraint was already to a SCIP instance
5646 - SCIPconshdlrGetNCutsApplied() in pub_cons.h to get the number of cuts applied to the lp
5647 - SCIPconshdlrIncNAppliedCuts() in cons.h to increase the number of applied cuts (used by sepastore.c)
5648 - SCIPchgVarName() and SCIPchgConsName() which can be used to change name of variables and
5649 constraints in problem creation stage
5650 - New methods SCIPgetConsVars() and SCIPgetConsNVars() which return for a given constraint the involved variables and
5651 the number of variables if the corresponding constraint supports this (optional) callbacks
5652 (corresponding callbacks need to be implemented, see above)
5655 - SCIPmessagehdlrCapture() which captures a given message handler (increases number of uses)
5656 - SCIPmessagehdlrRelease() which releases and possibly frees a given message handler (decreases number of uses)
5657 - SCIPsetMessagehdlrLogfile() which can be used to write into a log file
5658 - SCIPsetMessagehdlrQuiet() which can be used to turn the screen output on and off
5660### Command line interface
5662- in the interactive shell, parameters can be fixed and unfixed with `fix` (instead of `set`), e.g., `fix heuristics rens freq TRUE`;
5663- new shell command `change minuc` to minimize the number of unsatisfied constraints
5665### Interfaces to external software
5667- beta-version of a MATLAB interface can be found under interfaces/matlab
5668- beta-version of a AMPL interface can be found under interfaces/ampl
5670### Changed parameters
5672- `branching/fullstrong/reevalage` changed from an integer to a longint parameter
5674- Removed parameters:
5675 - `separating/closecuts/separootonly`
5676 - `constraints/quadratic/defaultbound`
5677 - `separating/cgmip/nodelimit`
5681- `constraints/%s/timingmask` for changing the timingmask for calling the propagtion method of all constraint plugins
5682- `constraints/and/dualpresolving` by default set to TRUE, enabling dual-presolving on and-constraints
5683- `constraints/indicator/{sepacouplingcuts,sepacouplinglocal}` to enable separation of (local) cuts
5684- `constraints/indicator/{maxsepacuts,maxsepacutsroot}` to restrict the number of separated cuts
5685- `constraints/indicator/dualreductions` to enable dual presolving/propagation steps
5686- `constraints/setppc/cliquelifting`, `constraints/setppc/addvariablesascliques`,
5687 `constraints/setppc/cliqueshrinking`, first for enabling/disabling the clique lifting algorithm in cons_setppc.c,
5688 second parameter is for trying to create extra clique constraints in lifting algorithm, third parameter is for trying
5689 to decrease the number of variable in a clique constraint in the lifting algorithm
5690- `limits/totalnodes` that allows to stop at the correct node if a restart occured; therefore the new
5691 `SCIP_STATUS_TOTALNODELIMIT` is added
5692- `lp/{rootiterlim,iterlim}` to set a limit on the LP iterations spend in the initial root LP and each
5693 LP resolve, respectively
5694- `misc/transorigsols` by default set to TRUE, that switches whether SCIP tries to transfer original
5695 solutions into the transformed space (in initsol and if a heuristic adds an original solution during solving)
5696- `numerics/hugeval` that defines the smalles value counting as huge (see new method SCIPisHugeValue())
5697- `numerics/recompfac` which denotes the factor, by which the absolute of an iteratively updated value has
5698 to be decreased in order to recompute the value from scratch
5699- `presolving/convertinttobin/maxdomainsize` by default is set to `SCIP_LONGINT_MAX`, which deternmines
5700 the domainsize for which integers are converted to their binary representation
5701- `presolving/convertinttobin/onlypoweroftwo` by default is set to FALSE, that parameter allows you to
5702 only convert integer variables with a domainsize of 2^p-1 to their binary representation
5703- `presolving/convertinttobin/samelocksinbothdirections` by default is set to FALSE, that parameter allows
5704 you to convert only integer variables to their binary representation, which have the same amount of up- and downlocks
5705- `presolving/gateextraction/sorting` by default is set to 1, that parameter determines if you want to try
5706 to extract big-gates(-1) or small-gates(1) at first by ordering bigger/smaller logicor constraint up front, or use
5707 them as they are (0)
5708- `presolving/gateextraction/onlysetpart` by default is set to FALSE, that parameter allows you to
5709 only extract set-partitioning and no and-constraints
5710- `presolving/gateextraction/searchequations` by default is set to TRUE, that parameter allows you to
5711 search for logicor constraints and set-packing/-partitioning constraints with same variables
5712- `propagating/%s/timingmask` for changing the timingmask for calling the propagtion method of all propagator plugins
5713- `propagating/probing/maxdepth` to set the maximal depth until the probing propagation is executed
5714- `reading/cnfreader/useobj` to state whether an artificial objective, depending on the number of clauses
5715 a variable appears in, should be used, by default set to FALSE, old default behavior of reader corresponds to TRUE
5716- `separating/cgmip/{minnodelimit,maxnodelimit}` to determine node limit.
5717- `separating/closecuts/maxlpiterfactor` for iteration limit in relative interior point computation
5718- `separating/oddcycle/maxunsucessfull` to automatically turn off separation
5719- `oncepernode` in Rounding and Simple Rounding heuristic
5723- new data structure for binary trees (`SCIP_BT` and `SCIP_BTNODE` in pub_misc.h)
5724- renamed data structure `SCIP_STAIRMAP` to `SCIP_PROFILE`
5725- added new stages `SCIP_STAGE_INITPRESOLVE`, `SCIP_STAGE_EXITPRESOLVE` and `SCIP_STAGE_FREE`; renamed `SCIP_STAGE_FREESOLVE`
5726 to `SCIP_STAGE_EXITSOLVE`
5727- Changed the counting system within SCIP heavily. `SPARSESOLUTION` was renamed to `SCIP_SPARSESOL` and moved
5728 from cons_countsols.h to struct_misc.h
5733- the check script now recognizes MIQCP and MINLP instances
5734- make test now also checks instances in wbo, cnf, osil and fzn format
5735- renamed parameter SCRDIR of `make testgams` to CLIENTTMPDIR and changed its default to `/tmp`
5742- CppAD source code is now distributed with SCIP (`src/cppad`), so that `lib/cppad` is not used anymore;
5743 the default for EXPRINT has changed from none to cppad
5748- fixed bug with strong branching with the LP status for conflict analysis
5749- fixed bug w.r.t. adding a value to the objective offset of the transformed problem
5750- fixed wrong assert in feasibility pump stage 3
5751- fixed bug in solve.c, applied bounding for the initial lp was only done if root-lp-solution was valid but another
5752 solution could also have been added
5753- primal solutions with infinite objective value are now automatically discarded
5754- all plugins that solve sub-SCIPs now do not stop the whole solution process if there has been an error
5755- fixed bug in cip reader, wrong use of SCIPstrtok()
5758 - fixed bug in shiftandpropagate w.r.t. SCIPconstructLP() which can have the side effect that variables are created
5759 - method SCIPvarGetProbvarSum() (and thus also SCIPgetProbvarSum()) returns +/-infinity if the variable resolves to a
5760 variable fixed to +/-infinity (depending on the sign of the scalar) but does not multiply with the scalar, anymore
5761 - better handling of infinite solution values for aggregated and negated variables
5762 - fixed bug that disabled multi-aggregation of two integer or implicit integer variables
5763 - fixed bug in sol.c with requesting values of transformed variables in original solution; previously this had only
5764 been handled in SCIPgetSolVal(), now the handling has been moved to SCIPsolGetVal()
5765 - fixed several bugs writing an mps file in the reader_mps.c, e.g. writing fixed variables which are not (yet) removed
5766 and writing integer variables even with an objective value of 0, if they only exist in non-linear constraints
5769 - fixed minor bugs with respect to counting generated and lifted cuts in sepa_oddcycle
5770 - fixed bug in sepa_clique.c, could not handle only empty cliques, that were not removed
5773 - fixed potential bugs in shiftandpropagate heuristic concerning the transformation update of a variable with free status
5774 - fixed bug in heur_zirounding with computation of up/downslacks
5775 - fixed bug in mutation heuristic with unnecessary aborts due to a wrong memory limit
5776 - fixed potential bug in fix-and-infer heuristic with variables being fixed to infinite value
5777 - fixed bug in diving heuristics with variables being fixed to values outside their domain
5778 - fixed bug in simple rounding heuristic with column generation for variables with strictly positive lower bound
5779 - made Octane heuristic numerically more stable to avoid asserts being caused by cancellation
5780 - fixed bug in mutation heuristic with variables being fixed to infinite values
5781 - do not run heur_shiftandpropagate if there is no LP
5784 - fixed bug in Cplex LPI: after running simplex, solisbasic flag was always true, which might be wrong if Cplex hit a
5786 - fixed bug in SCIP probing mode with cleared LPI state but solved LP
5787 - fixed assert with `LPI=none` (need to count rows/cols in lpi_none)
5788 - fixed bug in SoPlex LPI where objective sense was not correct after reading LP from file in SCIPlpiReadLP()
5791 - fixed bug in scip.c adding a constraint in SCIPgetConsCopy() to the constraint hashmap
5792 - fixed bug in cons_linear w.r.t recalculation of unreliable activities
5793 - fixed bug in cons_linear concerning huge activity values: besides infinite contributions, we now also treat huge
5794 contributions separately, count their occurences in a constraint and provide a relaxed activity value
5795 - fixed bug in cons_xor.c parsing a constraint
5796 - fixed count of propagations in cons_indicator and only try to propagate if variables are not yet fixed
5797 - fixed some bugs in cons_disjunction.c (wrong assert, forgotten deletion of constraint, wrong SCIPreleaseCons() call)
5802- first release of GCG, a generic branch-cut-and-price solver built on top of SCIP
5803- first release of UG, a framework for solving mixed integer programs, mixed integer
5804 nonlinear programs and constraint integer programs in parallel
5806- renamed ZIB Optimization Suite to SCIP Optimization Suite
5808@page RN2_1 Release notes for SCIP 2.1
5810@section RN212 SCIP 2.1.2
5811*************************
5813Performance improvements
5814------------------------
5816- fixed performance issue in debug mode, where SCIPvarGetLPSol_rec() calculated a value to often, which in the end lead
5817 to exponential growth in running time
5818- force cuts from linearizations of convex constraint in NLP relax solution into LP, thus allowing faster proving of
5819 optimality for convex NLPs
5824- fixed bug in varAddTransitiveImplic() in var.c, when adding implications on special aggregated, namely negated, variables
5825- fixed issue if a primal solution leads to a cutoff of the current focus node
5826- fix compilation issues with zlib 1.2.6
5827- fixed bug in SCIPsolveKnapsackExactly(), trying to allocate too much memory which led to an overflow and later to a segmentation fault
5828- fixed bug in sepa_rapidlearning, carrying on the optimization process, when already solved
5831 - fixed bug in heur_undercover.c, where a variable with fixed bounds but not of status `SCIP_VARSTATUS_FIXED` was wrongly handled
5832 - fixed bug in heur_oneopt.c which forgot to check LP rows if local rows are present
5835 - fixed bug in SCIPsolveKnapsackExactly()
5836 - fixed bug in cons_quadratic where bounds on activity of quadratic term were not always invalidated when quadratic variables were removed
5837 - fixed bug in cons.c, where after a restart the arrays for all initial constraints were corrected in the initsol process
5838 instead of the initpre process, this was to late because you might change the status in presolving which lead to an assert()
5839 - fixed bug in NLP representation of abspower constraints handling (x+a)^2 with nonzero a
5840 - fixed bug parsing an and-constraint in cip format
5841 - fixed bug in cons_setppc, did not handle new constraints with inactive variables
5842 - fixed bug in cons_xor.c which did not copy the artificial integer variable (used for the lp relaxation)
5844@section RN211 SCIP 2.1.1
5845*************************
5850- the pseudo objective propagator can be forced to propagate if active pricers are present; this can be done
5851 if for all (known or unknown) variables follows that: they have positive (negative) objective coefficient
5852 and the global lower (upper) bound is zero.
5854Performance improvements
5855------------------------
5857- improvements in undercover heuristic
5858- improve SCIPintervalSolveBivariateQuadExpressionAllScalar() for ax=0 case if x has 0 in the interval for the linear coef.
5859- better domain propagation for quadratic constraints that consist of `non-overlapping` bilinear terms only
5860- ensure that a fixing of a variable in an abspower constraint is propagated to a fixing of the other variable
5861- improvements in undercover heuristic, e.g., bound disjunction constraints are considered when setting up the covering problem
5866### Changed parameters
5868- changed parameter `propagating/pseudoobj/maxcands` to `propagating/pseudoobj/minuseless` (see prop_pseudoobj.c)
5869 due to revision of the pseudo objective propagator
5873- added parameters `heuristics/undercover/coverbd` and `heuristics/undercover/fixingorder`
5878- fixed numeric issue in aggregations
5879- fixed pseudo cost computation
5880- fixed bug with setting type of slack variables to be implicitly integral
5881- fixed bug when copying problem data in c++ case returned with the result `SCIP_DIDNOTRUN`
5882- fixed computation of counter which state the changes since the last call of a presolver
5883- fixed handling of unbounded solutions, including double-checking their feasibility and that the primal ray is a
5884 valid unboundedness proof and reoptimizing the LP with modified settings if the solution is not feasible
5885- fixed compilation issues with negate() function in intervalarith.c on exotic platforms
5886- fixed bug in SCIPsortedvecDelPos...() templates
5887- pseudo objective propagator does not propagate it active pricers are present
5888- fixed bug in heur_shiftandpropagate.c concerning the treatment of unbounded variables
5889- workaround for trying to add variable bounds with to small coefficients
5891- Reading and Writing:
5892 - gams writer now also substitutes $-sign from variable/equation names
5893 - fixed bug in reader_mps.c: INTEND marker is now also written, if COLUMNS section ends with non-continous variables
5894 - fixed bug in flatzinc reader w.r.t. boolean expressions
5897 - fixed constraint flags evaluation within the ZIMPL reader (reader_zpl.c)
5898 - fixed bug in SCIPmakeIndicatorFeasible() in cons_indicator.c
5899 - fixed bug with conflict clause modification in cons_indicator
5900 - fixed bug in cons_bounddisjunction with uninitialized return values
5901 - fixed bug in cons_orbitope with calling conflict analysis
5902 - fixed bug in nlpi_oracle w.r.t. changing linear coefs in a NLP constraint
5904@section RN210 SCIP 2.1.0
5905*************************
5910- New original solution storage capability, which allows transfering solutions between SCIP runs
5911- SCIP-CPX is now threadsafe
5912- comparison of solutions now also works for original solutions
5913- can now compute the relative interior point of the current LP
5914- interval arithmetics for power, log, exp, bivariate quadratic expressions should be rounding safe now
5915- LP iterations in resolving calls can now be limited w.r.t. the average number of LP iterations in previous calls
5916 (after the root node); this is currently only done for the initial LP solve at a node and the corresponding parameter
5917 resolveiterfac is set to -1 (no limit) per default
5918- it is now possible in `SCIP_STAGE_TRANSFORMED` to call SCIPaddVarLocks() (i.e. to lock variables in initialization methods)
5919- changed computation of optimality gap which is now done in the same way as described in the MIPLIB 2010 paper: the gap
5920 is 0, if primalbound (pb) and dualbound (db) are equal (within tolerances), it is infinity if pb and db have opposite
5921 signs and (this changed), if both have the same sign, the difference between pb and db is devided by the minimum of
5922 the absolute values of pb and db (instead of always the dual bound)
5923- functionality to use the bound flipping ratio test of SoPlex is available (requires at least version 1.5.0.7)
5924- there exists now a solution candidate store for the original problem; during transformation these solutions are tried;
5925 during free the transformed problem the best feasible solution of the transformed problem are copied to the solution
5926 candidate store of the original problem; this useful if you solve several problems iteratively, solutions get now
5927 carried over automatically.
5928- reworked concept of lazy bounds: they can now also be used for problems where constraints and objective together
5929 ensure the bounds; to allow this also for diving heuristics that might change the objective and thus destroy this
5930 property, lazy bounds are explicitly put into the LP during diving and removed afterwards
5931- `SCIP_HASHMAP` now works also without block memory
5932- The variable deletion event is now a variable specific event and not global, anymore.
5933- All timing flags are now defined type_timing.h.
5934- all C template files are now called <plugintype>_xyz.{c,h} instead of <plugintype>_xxx.{c,h}
5936- Separators and Cuts:
5937 - reorganized computation of scores in cut filtering: instead of the computation at the time of addition, scores are now
5938 only computed w.r.t. the current LP solution and when cut filtering is performed; one can now fill the cut storage
5939 with cuts that were separated for different solutions
5940 - New separator for close cuts and a new function to compute relative interior points of the LP
5941 - added first version of sepa_closecuts.{c,h} to separate cuts w.r.t. a point that is closer to the integral polyhedron
5944 - implement possibility to force a restart in cons_indicator if enough indicator variables have been fixed
5945 - the xor constraint handler can now parse its constraints
5946 - the bounddisjunction constraint handler can now parse its constraints
5947 - the knapsack, setppc and soc constraint handler can now parse their constraints
5948 - the varbound constraint handler can now parse its constraints
5949 - added beta version of variable deletion: for branch-and-price application, variables can now be completely deleted
5950 from the problem; variables that are deletable have to be marked with SCIPvarMarkDeletable(), constraint handlers can
5951 implement the new `SCIP_DECL_DELVARS` callback that should remove variables from the constraints; at the moment, only
5952 the linear, the setppc and the knapsack constraint handler support this callback; furthermore, when using this
5953 feature, all used plugins have to capture and release variables they store in their data, this is currently only done
5954 for the aforementioned constraint handlers as well as the and, the varbound and the logicor constraint handler; for
5955 more details about this feature, see the FAQ
5956 - added pseudoboolean constraint handler (cons_pseudoboolean.{c,h})
5957 - added first version of cons_disjunction.{c,h} which allows a disjunction of constraints
5958 - added constraint handler for (absolute) power constraints (cons_abspower.{c,h}) to handle equations like z = sign(x)abs(x)^n, n > 1
5961 - new heuristic vbounds which use the variables lower and upper bounds to fix variable and performs a neighborhood search
5962 - added vbound heuristic (heur_vbounds.{c,h})
5963 - added clique heuristic (heur_clique.{c,h})
5965- Reading and Writing:
5966 - added writing for wbo files
5967 - added writing for pip files (linear, quadratic, polynomial nonlinear, polynomial abspower, polynomial bivariate, and
5969 - CIP format variable characters defined, e.g. `SCIP_VARTYPE_INTEGER_CHAR`
5970 - Improved support for wbo format for weighted PBO problems, IBM's xml-solution
5971 format and pip and zimpl format for polynomial mixed-integer programs
5972 - New reader for (standard) bounds on variables
5973 - Extended reader for CIP models to handle various new constraints, including all types of linear constraints
5974 - flatzinc reader is now capable to read cumulative constraints
5975 - changed opb(/wbo) reader which now creates pseudoboolean constraints instead of linear- and and-constraints, only a
5976 non-linear objective will create and-constraints inside the reader and while reading a wbo file the topcost constraint
5978 - added clock for determine the time for reading
5979 - added reader for variable bounds (reader_bnd.{c,h})
5980 - Removed method SCIPreadSol(); call solution reading via SCIPreadProb() which calls the solution reader for .sol files.
5983 - Major extensions for nonlinear CIP, new option for n-ary branching on nonlinear variables (within pseudocost branching rule)
5984 - added BETA version of constraint handler for nonlinear constraints (cons_nonlinear.{c,h}) to handle nonlinear
5985 equations given by algebraic expressions using operands like addition, multiplication, power, exp, log, bivariate
5986 nonlinear constraints; currently no trigonometric functions
5987 - added BETA version of constraint handler for bivariate nonlinear constraints (cons_bivariate.{c,h}) to compute tight
5988 estimators for 1-convex and convex-concave bivariate nonlinear functions (given as expression tree)
5989 - the gams writer can now write nonlinear, abspower and bivariate constraints
5990 - Extended writer for GAMS and pip format to write more types of nonlinear constraints
5991 - the pip and zimpl reader now create nonlinear constraints for polynomials of degree > 2
5994 - new dual presolving methods in cons_setppc and cons_logicor
5995 - new presolving step `removeConstraintsDueToNegCliques` in locigor constraint handler which updates logicor constraints
5996 to setppc constraints if a negated clique inside this constraint exist, by default is off
5997 - new presolving step in cons_knapsack (detectRedundantVars, deleteRedundantVars) which determines redundant variables
5998 in knapsack constraint with or without using clique information
5999 - cons_logicor is now able to replace all aggregated variables in presolving by there active or negation of an active
6000 variable counterpart
6001 - prop_pseudoobj is now working in presolving as well
6002 - implement presolving in exitpre() in cons_orbitope and cons_indicator
6005 - added counter for number calls and timing for resolve propagation calls for constraint handler and propagators
6006 - Propagators are now also called in node presolving
6007 - the probing presolver presol_probing.{c.h} is now a propagator prop_probing.{c,h}, all corresponding parameters moved as well
6008 - the redcost separator sepa_redcost.{c.h} is now a propagator prop_redcost.{c,h}, all corresponding parameters moved as well
6009 - outsourced propAndSolve() method in solve.c which calls domain propagation and solving of the lp and relaxation
6012 - solutions which are given by the user from the outside are now marked by `#` in the output
6013 - the `Solving Time` is now spitted into presolving, solving and reading time
6014 - Presolvers section has new column `AddCons` which states the number of added constraint
6015 - Constraints section has new column named \#ResProp which show the number of resolve propagation calls of certain
6017 - Constraint Timing section has a new column \#ResProp which states the time spend in resolve propagation method of the
6019 - improved output of propagators in display statistics
6020 - new section `Propagator Timing` which shows the time spend in different callbacks of the propagator
6021 - rearranged first two columns of Propagators section; \#Propagate and \#ResProp stating the number of call for
6022 propagation and resolve propagation; the Time column is moved into the new section Propagator Timings
6023 - Constraints section has new column named `MaxNumber` which the maximum number of active constraint of a certain
6025 - added two columns `Time-0-It` and `Calls-0-It` in the LP section which states the number of LP call and time spend for
6026 solving LPs with zero iterations (only refactorization)
6027 - The display of statistics for presolvers, propagators, constraints and LP solving has changed.
6029Performance improvements
6030------------------------
6032- Reorganized filtering process of separation storage (allows adding cuts for different solutions)
6033- Improved presolving for various constraint handlers
6034- Improved propagation methods for variable bound constraints
6035- Improved performance for quadratic constraints
6036- performance improvements in prop_vbounds
6037- child selection rules now get also applied when the relaxation value is equal to the bound changed in branching
6038- added dual reduction to cons_cumulative.c
6039- for continuous variables, the pseudo costs update and the pscost branching rule now use the same strategies for
6040 updating the pseudo costs and estimating the improvement in the LP bound
6041- only perform probing if the variables are locked
6042- performance and memory consumption improvements in xmlparse.c
6043- Improved knapsack cover cuts
6044- avoid very long separation times of LEWIs in cons_knapsack for very large minimal covers
6045- used SCIPallocMemoryArray() instead of SCIPallocBlockMemoryArray() which leads to fewer memory consumption in
6046 getLiftingSequence() in cons_knapsack, also improved cache use bei using an extra array instead blockmemory chunks
6047- switched FASTMIP from 1 to 2 for CPLEX and changed default pricing rule back to steepest edge pricing instead of
6048 quickstart steepest edge pricing
6049- made sorting method more robust
6050- LNS heuristics now use SCIPcopy() by default
6051- considering inactive variables in undercover heuristic; limiting effort for solving covering problem
6052- if during probing mode the LP relaxation is solved from scratch, e.g., when calling the shiftandpropagate heuristic
6053 before root node solving, then we clear the resulting LP state, since it might be a bad starting basis for the next
6054 solve of the LP relaxation (controlled by new parameter `lp/clearinitialprobinglp`)
6055- included LP simplifier into SoPlex LP interface, applied when solving from scratch (lpi_spx.cpp)
6056- new presolving steps in varbound constraint handler, tightening bounds, coefficients, sides and pairwise presolving
6062 - The emphasis setting types now distinguish between plugin-type specific parameter settings (default, aggressive, fast, off),
6063 which are changed by SCIPsetHeuristics/Presolving/Separating(), and global emphasis settings (default, cpsolver, easycip,
6064 feasibility, hardlp, optimality, counter), which can be set using SCIPsetEmphasis().
6066### New and changed callbacks
6068- added propagator timings `SCIP_PROPTIMING_BEFORELP`, `SCIP_PROPTIMING_DURINGLPLOOP` and `SCIP_PROPTIMING_AFTERLPLOOP` for
6069 all propagation callbacks (see propagators and constraint handlers) which lead to calling the propagation methods of a
6070 propagator before the lp is solved, during the lp loop and after the lp solving loop
6073 - Added parameter `separate` to conflict handler callback method SCIP_DECL_CONFLICTEXEC() that defines whether the conflict
6074 constraint should be separated or not.
6076- Constraint Handler:
6077 - The new constraint handler callback SCIP_DECL_CONSDELVARS() is called after variables were marked for deletion.
6078 This method is optional and only of interest if you are using SCIP as a branch-and-price framework. That means,
6079 you are generating new variables during the search. If you are not doing that just define the function pointer
6081 If this method gets implemented you should iterate over all constraints of the constraint handler and delete all
6082 variables that were marked for deletion by SCIPdelVar().
6084- NLP Solver Interface:
6085 - The callbacks SCIP_DECL_NLPIGETSOLUTION() and SCIP_DECL_NLPISETINITIALGUESS() got new parameters to get/set values of
6087 - The callback SCIP_DECL_NLPICOPY() now passes the block memory of the target SCIP as an additional parameter.
6090 - New parameters `isunbounded` and `isinfeasible` for presolving initialization (SCIP_DECL_CONSINITPRE(),
6091 SCIP_DECL_PRESOLINITPRE(), SCIP_DECL_PROPINITPRE()) and presolving deinitialization (SCIP_DECL_CONSEXITPRE(),
6092 SCIP_DECL_PRESOLEXITPRE(), SCIP_DECL_PROPEXITPRE()) callbacks of presolvers,
6093 constraint handlers and propagators, telling the callback whether the problem was already declared to be
6094 unbounded or infeasible. This allows to avoid expensive steps in these methods in case the problem is already
6097 Note, that the C++ methods
6098 - scip::ObjConshdlr::scip_presol() corresponding to SCIP_DECL_CONSPRESOL()
6099 - scip::ObjConshdlr::scip_initpre() corresponding to SCIP_DECL_CONSINITPRE()
6100 - scip::ObjPresol::scip_initpre() corresponding to SCIP_DECL_PRESOLINITPRE()
6101 - scip::ObjProp::scip_initpre() corresponding to SCIP_DECL_PROPINITPRE()
6102 - scip::ObjConshdlr::scip_exitpre() corresponding to SCIP_DECL_CONSEXITPRE()
6103 - scip::ObjPresol::scip_exitpre() corresponding to SCIP_DECL_PRESOLEXITPRE()
6104 - scip::ObjProp::scip_exitpre() corresponding to and SCIP_DECL_PROPEXITPRE()
6105 are virtual functions. That means, if you are not adding the new parameters, your code will still compile, but these methods are not executed.
6106 - Propagators are now also called in during presolving, this is supported by the new callback methods SCIP_DECL_PROPINITPRE(),
6107 SCIP_DECL_PROPEXITPRE(), and SCIP_DECL_PROPPRESOL().
6108 - The new parameters `nnewaddconss` and `naddconss` were added to the constraint handler callback method SCIP_DECL_CONSPRESOL()
6109 and the presolver callback method SCIP_DECL_PRESOLEXEC(). These parameters were also added to corresponding C++ wrapper
6110 class methods (scip_presol() in objconshdlr.h and scip_exec() in objpresol.h)
6113 - The callback SCIP_DECL_PROBCOPY() got a new parameter `global` to indicate whether the global problem or a local version is copied.
6115### Deleted and changed API methods
6117- implemented SCIPlpiGetPrimalRay() in SoPlex interface that has become available with SoPlex version 1.5.0.2
6118- allowed calling SCIPgetRowSolActivity() in `SCIP_STAGE_SOLVED`, since LP is still available
6119- various extensions and modifications for expressions and expression trees (too much to state here)
6120- The result value `SCIP_NEWROUND` has been added, it allows a separator/constraint handler to start a new separation round
6121 (without previous calls to other separators/conshdlrs).
6122- SCIPcalcNodeselPriority() got a new parameter `branchdir`, which defines the type of branching that was performed: upwards, downwards, or fixed.
6124- Constraint Handlers:
6125 - Method SCIPincludeQuadconsUpgrade() of quadratic constraint handler got new parameter `active` to indicate whether the upgrading method is active by default.
6126 - Method SCIPseparateRelaxedKnapsack() in knapsack constraint handler got new parameter `cutoff`, which is a pointer to store whether a cutoff was found.
6128- Nonlinear expressions, relaxation, and solver interface:
6129 - SCIPcreateNLPSol() now creates a `SCIP_SOL` that is linked to the solution of the current NLP relaxation
6130 - Various types and functions dealing with polynomial expressions have been renamed to use the proper terms `monomial` and
6131 `polynomial` in nonlinear expressions (nlpi/∗expr*); results in many renamings of types, structs and methods.
6132 - The methods SCIPnlpGetObjective(), SCIPnlpGetSolVals(), and SCIPnlpGetVarSolVal() have been removed, use SCIPgetNLPObjval(),
6133 SCIPvarGetNLPSol() and SCIPcreateNLPSol() to retrieve NLP solution values instead.
6134 SCIPcreateNLPSol() now returns an error if NLP or NLP solution is not available
6135 - Removed methods SCIPmarkRequireNLP() and SCIPisNLPRequired(), because the NLP is now always constructed if nonlinearities
6137 - SCIPgetNLP() has been removed and NLP-methods from pub_nlp.h have been moved to scip.h, which resulted in some renamings, too.
6138 - renamed SCIPexprtreeEvalSol() to SCIPevalExprtreeSol() and now located in scip.h.
6139 - renamed SCIPexprtreeEvalIntLocalBounds() to SCIPevalExprtreeLocalBounds() and now located in scip.h.
6140 - renamed SCIPexprtreeEvalIntGlobalBounds() to SCIPevalExprtreeGlobalBounds() and now located in scip.h.
6141 - The functions SCIPnlpiGetSolution() and SCIPnlpiSetInitialGuess() got additional arguments to get/set dual values.
6142 - The method SCIPgetNLPI() got a new parameter `nlpiproblem`, which is a pointer to store the NLP solver interface problem.
6145 - SCIPincludeProp() got additional parameters to set the timing mask of the propagator and the new callbacks and parameters
6146 related to calling the propagator in presolving.
6147 - SCIPincludeConshdlr() got additional parameters to set the variable deletion callback function and the timing mask for
6149 - removed parameters timelimit and memorylimit from SCIPapplyRens()
6150 - The parameters `timelimit` and `memorylimit` were removed from SCIPapplyRens().
6153 - The method SCIPcopyProb() got a new parameter `global` to indicate whether the global problem or a local version is copied.
6155- Writing and Parsing Constraints:
6156 - The methods SCIPwriteVarName(), SCIPwriteVarsList(), and SCIPwriteVarsLinearsum() got a new boolean parameter `type`
6157 that indicates whether the variable type should be written or not.
6158 - The methods SCIPparseVarName() and SCIPparseVarsList() got a new output parameter `endptr` that is filled with the position
6159 where the parsing stopped.
6160 - The method SCIPwriteVarsList() got additionally a new parameter `delimiter` that defines the character which is used for delimitation.
6163 - SCIPmarkDoNotMultaggrVar()/SCIPvarMarkDoNotMultaggr() now allow to mark negated and aggregated variables
6164 - SCIPgetVarCopy() got a new parameter `success` that will be FALSE if method is called after problem creation stage and no hash map is
6165 given or no image for the given variable is contained in the given hash map.
6166 - SCIPchgVarType() got an extra boolean parameter to store if infeasibility is recognized while upgrading a variable from continuous
6167 type to an integer type.
6168 - SCIPdelVar() got a new parameter `deleted`, which stores whether the variable was successfully marked to be deleted.
6170### New API functions
6172- information about the quality of the solution of an LP (currently the condition number of the basis matrix) can now be:
6173 + requested from the LPI (currently only available for CPLEX): methods SCIPlpiGetRealSolQuality() and
6174 + SCIPprintLPSolutionQuality() command display lpsolquality in interactive shell display column lpcond to show
6175 + estimate on condition number, if available
6176- SCIPround() and SCIPfeasRound() to round to nearest integer
6177- SCIPsortRealRealIntInt() and corresponding sorting/inserting/deleting methods in pub_misc.h and necessary defines in misc.c
6178- SCIPsortRealIntLong(), SCIPsortPtrPtrRealInt() and corresponding sorting/inserting/deleting methods in
6179 pub_misc.h and necessary defines in misc.c
6180- SCIPcomputeLPRelIntPoint() to compute relative interior point of the current LP
6181- SCIPstartSolvingTime() and SCIPstopSolvingTime() which can be used to start or stop the solving time clock
6182- SCIPstrToRealValue() and SCIPstrCopySection() in pub_misc.h; these methods can be used to convert a string
6183 into a `SCIP_Real` value and to copy a substring.
6184- SCIPgetBinvarRepresentatives() which gets binary variables that are equal to some given binary variables,
6185 and which are either active, fixed, or multi-aggregated, or the negated variables of active, fixed, or multi-aggregated variables
6186- SCIPhasPrimalRay() and SCIPgetPrimalRayVal() that return whether a primal ray is stored and which value a
6187 given variable has in the primal ray, respectively
6188- SCIPsetConsModifiable()
6189- SCIPsetParam() which is a generic parameter setter method, independent of the parameter type
6190- SCIPpropInitpre(), SCIPpropExitpre(), SCIPpropPresol() which initializes, exists and executes the presolving phase
6191- SCIProwGetAge() to access the age of a row (pub_lp.h/lp.c)
6192- SCIPsolGetOrigObj() in pub_sol.h which returns for a solution in the original problem space the objective value
6193- SCIPretransformSol() in scip.h that allows to retransform a solution to the original space
6194- SCIPlpiClearState() to LP interfaces for clearing basis information in the LP solver
6195- SCIPgetSubscipDepth() to access the depth of the current SCIP as a copied subproblem
6196- SCIPdebugAddSolVal() and SCIPdebugGetSolVal() to add/get values to/from a debug solution
6197- SCIPsepastoreRemoveInefficaciousCuts() to remove non-efficious cuts from the separation storage
6200 - SCIPnodeGetParent() to get parent node of a node
6201 - SCIPnodesSharePath() in pub_tree.h that determines whether two nodes are on the same leaf-root path
6202 - SCIPnodesGetCommonAncestor() in pub_tree.h that finds the common ancestor node for two given nodes
6205 - SCIPgetReadingTime() which returns the time for reading in seconds
6206 - SCIPparseVarsLinearsum(), SCIPparseVarsPolynomial() and SCIPwriteVarsPolynomial() and for writing and
6207 parsing polynomials in constraint handler writing/parsing methods
6210 - SCIPcreateMesshdlrPThreads() and SCIPfreeMesshdlrPThreads() for allocating and deleting necessary memory
6211 for message handlers for parallel pthread version
6212 - SCIPallocClearMemoryArray() and BMSallocClearMemoryArray() for allocating cleared memory arrays in scip.h and memory.h
6215 - SCIPintervalPowerScalarInverse() to solve an equation y = x^p for given bounds on y and scalar exponent p
6216 - SCIPintervalQuadBivar() to compute tight bounds on a bivariate quadratic form
6217 - SCIPintervalSolveBivariateQuadExpressionAllScalar() to compute tight bounds on the solutions of a bivariate quadratic equation
6220 - SCIPcomputeVarCurrent{L,U}b{Local,Global}() to compute local or global lower or upper bounds of a
6221 multiaggregated variable from the bounds of the aggregation variables
6222 - SCIPbranchVarValNary() for n-ary variable branching
6223 - SCIPgetNegatedVars() which returns all negated variables for a given array of variables, if the negated
6224 variables are not existing yet, they will be created
6225 - SCIPgetNTotalVars() that returns the total number of created vars, icluding variables that were deleted in the meantime
6226 - SCIPvarGetHashkey(), SCIPvarIsHashkeyEq(), SCIPvarGetHashkeyVal() in pub_var.h which can be used for `SCIP_HASHTABLE` of variables
6227 - SCIPvarGetNBdchgInfosLb() and SCIPvarGetNBdchgInfosUb() in pub_var.h returning the number of lower or upper bound changes on the active path
6228 - SCIPvarGetBdchgInfoLb() and SCIPvarGetBdchgInfoUb() returning the bound change information at the given position
6229 - SCIPvarMarkDeletable() to mark a variable to be deletable completely from the problem (for
6230 branch-and-price); can only be called before the variable is added to the problem
6231 - SCIPvarMarkNotDeletable() that marks a variable to be non-deleteable (used within SCIP for forbidding
6232 deletion of variables contained in solution, LP bases, (multi)aggregation, ...)
6233 - SCIPvarIsDeletable() that returns whether a variable is marked to be deletable (each variable is per default non-deletable)
6236 - SCIPgetNLPVarsNonlinearity() to get for each variable in the NLP the number of NLP rows in which this variable appears in a nonlinear way
6237 - SCIPnlrowGetDualsol(), SCIPgetNLPVarsLbDualsol(), SCIPgetNLPVarsUbDualsol() to retrieve dual values from an NLP solution
6238 - SCIPgetNLPFracVars() to get the fractional variables in an NLP solution
6241 - SCIPpropSetPresolPriority() which changes the presolving priority of a given propagator
6242 - SCIPpropGetPresolPriority(), SCIPpropGetPresolTime(), SCIPpropWasPresolDelayed(), SCIPpropGetNFixedVars(),
6243 SCIPpropGetNAggrVars(), SCIPpropGetNChgVarTypes(), SCIPpropGetNChgBds(), SCIPpropGetNAddHoles(), SCIPpropGetNDelConss(),
6244 SCIPpropGetNAddConss(), SCIPpropGetNUpgdConss(), SCIPpropGetNChgCoefs(), SCIPpropGetNChgSides(), SCIPpropGetTimingmask(),
6245 SCIPpropDoesPresolve() which return corresponding presolving information
6246 - SCIPpropGetNRespropCalls() and SCIPconshdlrGetNRespropCalls() which return the number of times a
6247 propagator or a constraint handler was called for resolving a propagation
6248 - SCIPpropGetRespropTime() and SCIPconshdlrGetRespropTime() which return time spent for resolving a
6249 propagation within a propagator or a constraint handler
6250 - SCIPcheckCumulativeCondition(), SCIPpropCumulativeCondition() and SCIPrespropCumulativeCondition() in
6251 cons_cumulative.h; these methods can be used to check, propagate, or resolve the propagation of a cumulative condition
6252 - SCIPpropagateCutoffboundVar() in prop_pseudoobj.h which can be used to propagate the cutoff bound for the given variables
6255 - added to linear constraint handler SCIPsetUpgradeConsLinear(), which (de-)activates the possibility to
6256 upgrade a linear constraint to a specialized linear constraint (e.g. knapsack)
6257 - SCIPconvertCutsToConss() and SCIPcopyCuts() to scip.{c,h} for copying cuts to linear constraints
6258 - SCIPaddCoefLogicor() to add a variable to a logic or constraint
6259 - SCIPfindOrigCons() which return a original constraint with the given name or `NULL`
6260 - SCIPconshdlrGetNAddConss() which returns the number of added constraints during presolving by a given constraint handler
6261 - SCIPpresolGetNAddConss() which returns the number of added constraints during presolving by a given presolver
6263### Command line interface
6265- New funtionalities in the interactive shell (modify current CIP instance, write NLP relaxation)
6266- added dialog `write nlp` to write current NLP relaxation to a file
6267- new dialog `change freetransproblem` to free transformed problem in the interactive shell before changing the problem
6268- it is possible to change bounds of a variable in the interactive shell
6269- it is possible to add a constraint to a problem in the interactive shell
6271### Interfaces to external software
6273- Improved SOPLEX interface (LP simplifier)
6274- Improved CPLEX interface, including measures for numerical stability
6276### Changed parameters
6278- change default value of parameter `nodeselection/restartdfs/selectbestfreq` 100
6279- moved parameters for pseudoboolean constraints from opb-reader to pseudoboolean constraint handler
6280- changed possible parameter values of `branching/pscost/strategy` from `bri` to `cdsu`: default is now `u`, i.e., to
6281 estimate the LP gain by a branching for external branching candidates (esp. continuous variables) the same way as
6282 their pseudo costs are updated
6283- added possible value `d` for `constraints/soc/nlpform` to choose a convex division form for SOC constraint
6284 representation in NLP
6285- renamed parameter `constraints/quadratic/linearizenlpsol` to `constraints/quadratic/linearizeheursol` and do
6286 linearizations in every solution found by some heuristic
6287- renamed parameter `constraints/quadratic/mincutefficacyenfo` to `constraints/quadratic/mincutefficacyenfofac` and
6288 interpret it as a factor of the feasibility tolerance
6289- removed fastmip setting 2, which means the dualsolution would not be calculated but because SCIP always asks for the
6290 dual solution, the lp would be reoptimized to calculate them; so it had no real effect
6291- all parameters in cons_indicator and cons_sos1 have been converted to lower case!
6292- changed default value of parameter `separating/gomory/maxroundsroot` to 10
6293- changed default value of parameter `separating/gomory/maxsepacutsroot` to 50
6294- removed parameter `heuristics/subnlp/nlpsolver`, use `nlp/solver` instead
6298- `branching/delaypscostupdate` to delay the update of pseudo costs for continuous variables behind the separation round: default is TRUE
6299- `branching/lpgainnormalize` to set the strategy how the LP gain for a continuous variable is normalized when updating the
6300 variables pseudocosts: default is to divide LP gain by reduction of variable's domain in sibling node
6301- `branching/pscost/nchildren` and `branching/pscost/nary*` to enable and customize n-ary branching on
6302 external branching candidates (e.g., in spatial branching for MINLP)
6303- `conflict/bounddisjunction/continuousfrac` which defines the maximum percantage of continuous variables
6304 within a conflict create by the bounddisjunction conflict handler
6305- `conflict/separate` which enables or disables the separation of conflict constraints
6306- `constraints/{nonlinear,quadratic,soc,abspower}/sepanlpmincont` to specify minimal required fraction
6307 of continuous variables in problem to enable linearization of convex constraints in NLP relaxation solution in root
6308- `constraints/indicator/forcerestart` and `constraints/indicator/restartfrac` to control forced restart in cons_indicator
6309- `constraints/indicator/generatebilinear` to generate bilinear (quadratic) constraints instead of indicator constraints
6310- `constraints/indicator/maxconditionaltlp` to enable a quality check for the solution of the alternative LP
6311- `constraints/indicator/removeindicators` to remove indicator constraints if corresponding vub has been added
6312- `constraints/linear/nmincomparisons` and `constraints/linear/mingainpernmincomparisons` to influence
6313 stopping criterium for pairwise comparison of linear constraints
6314- `constraints/pseudoboolean/decompose`, for pseudoboolean constraints to transform pseudoboolean constraints into linear- and and-constraints
6315- `constraints/quadratic/binreforminitial` to indicate whether linear (non-varbound) constraints added due to reformulation of products with
6316 binary variables in a quadratic constraints should be initial (if the quadratic constraint is initial), default is FALSE
6317- `constraints/quadratic/checkfactorable` to disable check for factorable quadratic functions (xAx = (ax+b)*(cx+d)) in quadratic constraints
6318 and not to use of this information in separation (generates lifted tangent inequalities according to Belotti/Miller/Namazifar if also
6319 linear vars are present)
6320- `constraints/quadratic/disaggregate` to split a block-separable quadratic constraint into several quadratic constraint
6321- `constraints/quadratic/maxproprounds` and `constraints/quadratic/maxproproundspresolve` to limit the
6322 number of propagations rounds for quadratic constraints within one propagation round of SCIP solve or during SCIP presolve
6323- `constraints/varbound/presolpairwise` that allows pairwise presolving of varbound constraints, default is TRUE
6324- `heuristics/shiftandpropagate/onlywithoutsol` to switch whether the heuristic should be called in case a primal solution is already present
6325- `limit/maxorigsol` which defines the size of the solution candidate store (default value is 10)
6326- `lp/resolverestore` controlling how LP solution is restored after diving: if TRUE by resolving them,
6327 if FALSE by buffering them; if `lp/freesolvalbuffers` is TRUE, we free the buffer memory each time (FALSE by default)
6328- `lp/clearinitialprobinglp` to clear LP state at end of probing mode, if LP was initially unsolved
6329- `lp/resolveitermin` and `lp/resolveiterfac` to limit the number of LP iterations in resolving calls:
6330 resolveiterfac is a factor by which the average number of iterations per call is multiplied to get the limit, but the
6331 limit is at least resolveitermin; default is -1 (no limit) for resolveiterfac and 1000 for resolveitermin
6332- `lp/resolverestore` and `lp/freesolvalbuffers` possibility to buffer and restore LP solution after diving without
6333 having to resolve the LP; currently turned off, because performance impact is unclear;
6334- `misc/improvingsols` which states whether only solutions which have a better (or equal) primal bound
6335 as the best known are checked; this is of interest if the check of a solution is expensive; default value is FALSE
6336- `misc/resetstat` which state if the statistics should be reseted if the transformed problem is freed
6337 (in case of a benders decomposition this parameter should be set to FALSE) default value is TRUE
6338- `nodeselection/restartdfs/countonlyleafs` in node selector restart dfs which can be used to select the counting process of processed nodes
6339- `presolving/donotaggr` to deactivate aggregation of variables globally
6340- `pricing/delvars` and `pricing/delvarsroot` that define, whether variables created at a node / the
6341 root node should be deleted when the node is solved in case they are not present in the LP anymore
6342- `propagating/%s/maxprerounds` for all propagators which allows to change to maximal number of rounds
6343 of presolving where this propagator participates in
6344- `propagating/%s/presoldelay` for all propagators which allows to change if the presolving call of the given propagator should be delayed
6345- `propagating/%s/presolpriority` for all propagators which allows to change the priority of calling the given propagator
6346- `propagating/pseudoobj/propfullinroot` for allowing to propagate all variables in the root node,
6347 instead of stopping after `maxcands` which is set by a parameter as well
6348- `reading/gmsreader/bigmdefault` and `reading/gmsreader/indicatorreform` reader_gms is now able to write indicator
6349 constraints (reformulated either via big-M or sos1)
6350- `reading/gmsreader/signpower` to enable writing sign(x)abs(x)^n as the rarely used gams function signpower(x,n)
6351- `separating/closecuts/maxunsucessful` to turn off separation if we can not find cuts
6352- `timing/reading` to add reading time to solving time
6356- split off `PARAMEMPHASIS` from `PARAMSETTING` (in pub_paramset.c/paramset.c)
6357- new data structure `SCIP_STAIRMAP`
6358- add expression graph data structures and methods for reformulation, domain propagation, simple convexity check on
6359 nonlinear expressions and simplification for expression trees and graphs
6364- New scripts for running tests with GAMS
6365- added scripts check_gams.sh, evalcheck_gams.sh and check_gams.awk and target `testgams` in Makefile
6366- adjusted all test scripts to use the same new optimality gap computation as in SCIP
6367- added Makefile option `VALGRIND=true` to enable running the SCIP checks (make test) through valgrind; valgrind errors
6368 and memory leaks are reported as fails
6369- moved *.test and *.solu files to subdirectory testset in check directory and adjusted test scripts
6377 - via `PARASCIP=true` as a `Makefile` option it is possible to compile SCIP threadsafe in DEBUG-mode, (in OPT-mode it's
6378 only necessary if non-default messagehandler or CppAD is used)
6379 - the `make` parameter `PARASCIP=true` leads to threadsafe message handlers where you need to call
6380 SCIPcreateMesshdlrPThreads() and SCIPmessageSetHandler()/SCIPmessageSetDefaultHandler() and SCIPfreeMesshdlrPThreads();
6381 therefore we need to link with pthread library
6382 - new variable $(INSTALLDIR) in Makefile which define installation directory for the libraries, $(INSTALLDIR)/lib/,
6383 binary, $(INSTALLDIR)/bin and include headers, $(INSTALLDIR)/include, the default value is the empty string
6386 - Linking against Clp and Ipopt has been simplified. Only the directory where the
6387 package has been installed need to be provided now. For details see the INSTALL file.
6388 - to link against IPOPT, only the base directory of an Ipopt installation need to be specified now; additionally, if
6389 building with gnu compilers, the Ipopt libraries directory is stored in the SCIP binary, which should make it easier
6390 to run with Ipopt shared libraries
6391 - to link against Clp, only the base directory of an Clp installation needs to be specified now
6394 - New targets `(un)install` in Makefile, support for valgrind in testing environment
6395 - new target `make libs` which compiles only the libraries
6396 - new target in Makefile `install` performs `make` and copies using the install command the include headers, binary, and
6398 - new target in Makefile `uninstall` removes libraries, binary and include headers form `INSTALLDIR`
6399 - removed target `lintfiles`, this target is now imitated by the `lint` target and a none empty variable `FILES`
6404- fixed bug in copying if the target SCIP already is in solving stage: it might be that the copy of a variable cannot be found/created
6405- fixed bug trying to print big messages bigger than `SCIP_MAXSTRLEN`
6406- fixed bug w.r.t. counting feasible solutions and turned of sparse solution test
6407- LP solution status is now checked when checking root LP solution. Otherwise, due to different time measurements, it
6408 might happen that the LP solving was stopped due to the time limit, but SCIP did not reach the limit, yet.
6409- fixed bug trying to tighten multiaggregated variables, which have only one active representation and this variable is already tightened
6410- fixed possible buffer overrun in tclique_graph.c
6411- fixed issue with interactive shell in case (user) plugins are included after the default plugins
6412- fixed bug where mutiaggregating leads to an aggregation and both variables were of implicit or integral type
6413- fixed bug in conflict.c, where LPi was manipulated, but not marked as not solved
6416 - fixed assertion in tree.c w.r.t. node estimation
6417 - fixed bug in debug.c: removed tree nodes had not been checked if they were pruned due to an incumbent solution found by a diving heuristic
6420 - fixed bug which occured when changing a bound in the solving stage when this variables got upgraded from continuous to
6421 a integer type, where the bounds of this variable were still not integral; due to that SCIPchgVarType() has changed (see above)
6422 - fixed bug in handling of lazy bounds that resulted in putting the bounds explicitly into the LP
6425 - fixed assert in sepa_clique.c which is currently not valid because implicit binary variables in cliques are ignored
6426 - fixed bug in sepa_zerohalf.c concerning inconsistent construction of solution array of variables and fixed wrong assert about variable bounds
6429 - fixed not correct merging of variable in logicor constraint handler and changed the name of the method to a common
6430 name used by other constraint handlers too(findPairsAndSets->mergeMultiples)
6431 - fixed bugs in changing the initial and checked flags for constraints in original problem
6432 - fixed bug in cons_linear.c, when scaling a constraint maxabscoef was not set correctly, furthermore the correction of
6433 maxabscoef was not handled correctly
6434 - fixed bug in cons_indicator.c trying to copy a constraint where the pointer to the linear constraint did not point to
6435 the already transformed linear constraint (, happend when SCIPcopy() is used after transforming before presolving)
6436 - fixed numerical bug in linear constraint handler: polishing of coefficients after fixing variables led to wrong
6437 results for continuous variables fixed to a close-to-zero value.
6438 - fixed bug in cons_bounddisjunction where branching on multiaggregated variables was tried while all aggregation variables are fixed
6439 - fixed bug in presolving of cons_logicor.c: adding variable implications can lead to further reductions; added call to applyFixings()
6440 - fixed bug in cons_countsols.c w.r.t. none active variables
6441 - fixed bug in cons_linear.c, scaling could have led to wrong values
6444 - fixed bug in reader_fzn.c w.r.t. cumulative constraints
6445 - fixed bug in reader_mps.c: if a variables first occurence is in the bounds section, then the corresponding variable bound was lost
6446 - fixed several issues in flatzinc reader
6447 - deactived checking of zero solution in Zimpl reader when no starting values are provided
6448 - reader_lp is now able to read lines longer than 65534 characters
6451 - fixed bug in copying NLPI interfaces that use block-memory (NLPI copy used block memory from source SCIP)
6452 - fixed memory leak in reader_pip.c
6453 - fixed memory leak in coloring part of maximum clique algorithm (tclique_coloring.c)
6454 - fixed memory leak in coloring part of maximum clique algorithm (tclique_coloring.c) in a better way
6457 - fixed bug which occured when the dual farkas multipliers were not available in the lpi because the LP could only be
6458 solved with the primal simplex due to numerical problems
6459 - fixed bug in ZI round heuristic that led to infeasible shiftings for numerically slightly infeasible rows with close-to-zero coefficients
6460 - fixed numerical issue in octane heuristic: close-to-zero values for ray direction could have led to bad computations
6463 - fixed bug in propagation of indicator constraints: cannot fix slack variable to 0 if linear constraint is disabled/not active
6464 - fixed bug in cons_linear.c while sorting the eventdatas during the binary variable sorting for propagation
6465 - fixed bug and wrong assert in heur_shiftandpropagate.c when relaxing continuous variables from the problem
6466 - fixed bug in cons_orbitope:resprop() for the packing case
6467 - fixed wrong changing of wasdelayed flag for propagators
6468 - fixed bug using wrong sign in infinity check in prop_pseudoobj
6469 - fixed bug in redcost propagator: can only be called if the current node has an LP
6470 - fixed bug w.r.t. infinity loop during propagation
6475- The interface contains several additional callback functions and parameters for plugins. Some effort may be required to compile your old
6476 projects with SCIP 2.1. For details see section `Changes between version 2.0 and 2.1` in the doxygen documentation.
6478@page RN2_0 Release notes for SCIP 2.0
6480@section RN202 SCIP 2.0.2
6481*************************
6483Performance improvements
6484------------------------
6486- improved twoopt-heuristic by considering larger search domains
6487- the SoPlex interface now has the capability to provide a primal ray, provided it is compiled against the next SoPlex release (>= 1.5.0.2)
6488- calculation of node priority now also works when variable's relaxation value is equal to a bound
6489- fixed issue w.r.t. calling primal heuristics after presolving detected infeasibility
6492 - fasten propagation in cons_knapsack.c due to negated clique partitions
6493 - recalculating only needed partitions in cons_knapsack.c, not always both
6496 - reduced memory usage of shift-and-propagate heuristic
6497 - knapsack constraints are now separated faster; SCIPsolveKnapsackExactly() now works faster and requires less memory
6498 - fasten knapsack separation by replacing SCIPallocBuffer(Array) through SCIPallocBlockMemory(Array)
6499 - improved runtime and memory consumption in SCIPsolveKnapsackExactly() in cons_knapsack.c
6504- fixed `make/make.project`
6505- fixed wrong assert in plugins that use SCIPcopy()
6506- fixed bug in DINS w.r.t. column generation
6507- fixed bug in var.c where a possible multiaggregation was resolved to an aggregation but the variables types were not
6508 checked to prefer more general types for aggregating; possible memory loss removed
6509- fixed bug in prop_vbounds.c w.r.t. infinity lower and upper bound of variable bound variables
6510- fixed bug w.r.t. setting wall clocks
6511- fixed wrong assert in var.c (replaced `==` through SCIPsetIsEQ()), real values do not have to be exactly the same when
6512 computed in different function
6513- fixed bug in SCIPsolveIsStopped() where it could happen that TRUE was reported if a nodelimit was reached but
6514 checknodelimits had been set to FALSE
6515- fixed three bugs when writing in fzn format (wrongly splitted writing buffer, wrong variables was used, floats were printed to short)
6516- fixed bug in conflict.c, infeasibility analysis with big values led to wrong result
6519 - fixed bug in DINS heuristic that occured when the incumbent solution value is outside the variable's current domain
6520 - fixed behavior of LNS heuristics when the subproblem aborts: continue in optimized mode, stop in debug mode
6521 - fixed segmentation fault in heur_subnlp.c which occured if resolving the NLP with a tighter feasibility tolerance
6522 failed with a solver error
6523 - fixed bug in heur_subnlp.c where constraints forbidding variable fixations where added if a cutoff was used in the subproblem
6524 - fixed bug in heur_subnlp.c where wrong constraints forbidding variable fixations where added in case of general integers
6527 - fixed bug in changing quadratic coefficients of a row in the NLP
6528 - fixed various small bugs in nonlinear expressions code
6529 - fixed removal of fixed linear variables from a nonlinear row: a fixed variable may have not been removed if there was
6530 also a multiaggregated variable
6533 - implemented SCIPlpiGetPrimalRay() in SoPlex interface that has become available with SoPlex version 1.5.0.2
6534 - fixed two bugs at nodes with unbounded LP relaxation: don't check lp rows of infinite solution; don't analyze conflict
6535 due to primal cutoff bound of -infinity
6536 - fixed wrong assumption that an optimal LP solution in the root is optimal for the problem if there are no active
6537 pricers, need to check also whether all variables are in the LP
6540 - fixed bug in reader_cip regarding reading of very long constraints
6541 - fixed bug while after restarting possible the aggregted variables were not removed in setppc constraints
6542 - fixed bug in cons_knapsack: in seldom circumstances the relaxation of a linear constraint can detect infeasibility,
6543 which was not handled properly
6544 - fixed bug w.r.t. to pricing variables in case new initial constraints come in during the price and cut loop
6545 - fixed bug in cons_soc.c w.r.t. upgrading from quadratic constraints with finite left-hand-side
6546 - fixed bug caused by not (correctly) counting boundchanges in cons_varbound.c
6547 - fixed bug in sorting mechanism in cons_xor.c
6548 - fixed wrong (neg)cliquepartition check in cons_knapsack.c when deleting a coefficient
6549 - fixed bug in cons_quadratic: in seldom cases, fixed variables may have been substituted out wrongly in presolve
6550 - fixed bugs in cons_countsols.c w.r.t. collecting feasible solutions and forbidding a found solution
6551 - fixed bug in cons_linear.c: multiaggregated variables were not removed when adding during solve, leading to a failing
6552 assert in tightenBounds due to an unsuccessful bound tightening
6555 - fixed bug concerning overflow in memsize calculation in set.c
6556 - fixed memory leak in SoPlex LP interface when requesting an unbounded solution
6557 - fixed memory leak in SoPlex LP interface when solving with LP scaling
6558 - fixed memory leaks in reader of TSP example
6560@section RN201 SCIP 2.0.1
6561*************************
6563Performance improvements
6564------------------------
6566- SCIP with SoPlex as LP solver now uses auto pricing by default (start with devex, switch to steepest
6567 edge after some iterations); this fixes timeouts on instances where devex converges very slowly
6568- fixing lifting of new knapsack items which are negated items of already included items, this could lead to very long presolving
6569- fixed performance issue in presolving w.r.t. to computing the number of new fixings, aggregated,
6570 and so on before a constraint handler presolver is called
6571- in case of adding constraints during pricing with initial flag set to
6572 TRUE, we add now these constraints after the pricing round to the LP
6573- changed parameter values in clique separator in order to avoid very large branch-and-bound trees
6578### New and changed callbacks
6580- allow access of transformed constraints in `SCIP_STAGE_TRANSFORMED`
6582### Changed parameters
6584- replaced parameter `constraints/quadratic/minefficacy` by `constraints/quadratic/minefficacysepa` and `constraints/quadratic/minefficacyenfo`
6585- added possible values `a` and `e` for `constraints/soc/nlpform` to enable automatic choice and convex exponential-sqrt
6586 form for SOC constraint representation in NLP
6591- fixed bug w.r.t. looseobjval; the counting of number of loose variables in the LP data structure was incorrect in case
6592 a variable got aggregated or multi-aggregated
6593- fixed bug in copy method of objvardata which should only create a new `SCIP_VARDATA` if the implemented subclass create
6594 a copy of the given objvardata object
6595- fixed bug in lp.c where in case of objlimit reached and fastmip not all variables where priced because of an incorrect
6597- fixed bugs in binpacking example w.r.t. empty struct and not initializing an array
6598- fixed bugs in sepa_clique.c concerning incorrect way to ignore implicit binary variables in cliques and non-active
6599 variables in implications
6600- fixed some bugs w.r.t. to casting pointer arrays
6601- fixed bug in vars.c which handled arrays with parts of original variables during resolving to active variables (using
6602 SCIPvarsGetProbvarBinary) wrong
6603- fixed bug in nlp.c: nlrowSearchQuadElem was using SCIPquadelemSortedFind() incorrectly
6606 - fixed assertion w.r.t. to probing during the propagation round of a branch-and-bound node
6607 - fixed computation of node's objective value estimate when branching on continuous variables (see
6608 SCIPtreeCalcChildEstimate(), SCIPtreeBranchVar())
6609 - fixed bug in statistic w.r.t. number of calls for external branching candidates
6610 - fixes to branching on continuous variables
6613 - fixed bug in reader_gms.c: linear coefficients for quadratic variables were not printed if they had no
6615 - fixed bug in reader_mps: indicator constraints do not output the slack variables anymore
6618 - fixed bugs in SCIPcopyConss: copy all active constraints (including disabled ones), *valid was not initialized to TRUE
6619 - fixed bug in debug.c w.r.t. checking of constraints and continuous variables
6620 - fixed bug in cons.c which didn't allow the changing of the separation and enforcement flag of a constraint in the
6622 - corrected behavior of the copy function in cons_indicator.c: create artificial linear constraint if linear constraint
6624 - fixed bug in cons_indicator.c: presolving cannot delete linear constraints; several other minor bugfixes
6625 - fixed bugs in cons_bounddisjunction where the branching during the constraint enforcement was done incorrectly
6626 - fixed bugs in cons_orbitope.c: orbitopal fixing for the packing case had two bugs; also fixed one wrong assert
6627 - fixed bugs in cons_sos?.c: take average of objestimate
6628 - fixed bug in cons_logicor, implications on none `SCIP_VARTYPE_BINARY` variable were handled wrong
6629 - fixed bug in cons_linear while trying to add a conflict without any variables
6630 - fixed bug in cons_indicator.c: creating constraints in transformed stage is now possible
6633 - fixed bug w.r.t. memory allocation for all values of a column in lpi_cpx.c
6634 - fixed bugs in SCIPnlpiOracleChgLinearCoefs() and SCIPnlpiOracleChgQuadCoefs() for the case where new coefficients where
6636 - fixed bugs in lpi_none.c w.r.t. debug and opt mode
6637 - fixed bug in lpi_cpx.c w.r.t. to wrong handling in case the crossover did not succeed
6640 - fixed bug in heur_subnlp when initialized starting values of a fixed variable in the NLP of the subscip
6641 - fixed bug in heur_undercover: removed option globalbounds, since we are not allowed to relax bounds at a probing node
6642 - fixed bug in heur_shiftandpropagate where some variables were initialized too late
6643 - fixed numerical issue in some heuristics: nearly-integral values that are between the feasibility and the integrality
6644 tolerance might not have been rounded correctly
6645 - fixed bug in heur_guideddiving: best solution is now copied to avoid deletion in case of many new solutions
6646 - fixed bug in DINS heuristic, information storage for binary variables could lead to bad memory access in column
6647 generation applications
6648 - fixed bug in heur_shiftandpropagate.c: Now, the heuristic checks rows for global infeasibility at the beginning. This
6649 check is only relevant if presolving is disabled.
6650 - fixed bug in heur_subnlp when forbidding a particular combination of integer variables in the main problem
6652@section RN200 SCIP 2.0.0
6653*************************
6658- added relaxation structure to SCIP, it represents global relaxation information independent from a specific relaxator;
6659 at the moment, it contains information about the relaxation solution stored in the variables: objective value and
6661- SCIP may now be manually restarted
6662- SCIPsolveKnapsackExactly() got a new 12. parameter `SCIP_Bool* success` which stores if an error occured during
6663 solving(normally a memory problem)
6664- SCIP can now handle problems with continuous variables w.r.t. to counting (the projection to the integral variables
6666- an XML-parser is available in the src/xml subdirectory
6667- We do not distinguish between block memory for the original and the transformed problem anymore. The same
6668 block memory is now used in both problem stages.
6669- added new sorting method SCIPsortLongPtr(), SCIPsortDownLongPtr() and all corresponding methods
6670- added new sorting method SCIPsortRealIntPtr(), SCIPsortDownRealIntPtr() and all corresponding methods
6673 - SCIP can now copy instances (e.g. for heuristics)
6674 - new undercover heuristic for MINLPs: fixes variables such as to obtain a linear or convex subproblem and solves this
6675 - primal heuristics may now already be called before presolving, using the new timing point
6676 `SCIP_HEURTIMING_BEFOREPRESOL`. Note that solutions that are added before/during presolving, will be retransformed to
6678 - primal heuristics may now be called during presolving, using the new timing point `SCIP_HEURTIMING_DURINGPRESOLLOOP`
6679 - added heuristic zirounding (heur_zirounding.{c,h})
6680 - added heuristic twoopt (heur_twoopt.{c,h})
6681 - added new NLP heuristic (heur_subnlp.{c,h}) which solves the sub-NLP that is obtained by fixing all discrete variables
6682 in the CIP and applying SCIP's presolving
6683 - feasibility pump heuristic now implements all functionality for feasibility pump 2.0
6686 - can now read XML-solution files as used by CPLEX
6687 - the MPS reader can now read MIQPs and MIQCPs where a quadratic objective function can be specified by a QMATRIX or
6688 QUADOBJ section and the quadratic part of a quadratic constraint by a QCMATRIX
6689 - the MPS reader can now write quadratic and SOC constraints
6690 - the GAMS reader can now write SOC constraints
6691 - added support for bool_gt, bool_lt, bool_ge, bool_le, bool_ne, bool_not, int_times, int_minus, int_plus, int_negate,
6692 float_times, float_minus, float_plus, float_negate constraints to flatzinc reader
6693 - the LP reader (.lp files) can now read MIQPs and MIQCPs and write quadratic and SOC constraints
6694 - the LP reader (.lp files) and MPS reader can now read semicontinuous variables, they are handled by creating bound
6695 disjunction constraints
6696 - added new reader for polynomial mixed-integer programs (reader_pip.{c,h}) as used in the POLIP
6698- Indicator constraints:
6699 - SCIP can now handle indicator constraints (reading (from LP, ZIMPL), writing, solving, ...) see \ref cons_indicator.h.
6700 - the indicator constraint can now decompose the problem, i.e., not add the linear constraint to the problem if all of
6701 its variables are continuous
6702 - can now read and write indicator constraints in the (extended) MPS format
6703 - cons_indicator tries to adapt solutions to get feasible during check
6704 - cons_indicator allows to store information on other linear constraints that might help to separate cuts
6706- Constraint handlers:
6707 - Solution counting extended to constraint integer programs, this also
6708 includes constraint integer programs which contain continuous variables
6709 - The solution behavior of SCIP can be diversified by randomly permuting constraints and variables or randomly
6710 determining a set of branching variables with a unique high priority
6711 - `negated cliques` (1<=i<=n : sum (x_i) >= n-1) were added and we are using them now inside the knapsack constraint
6712 handler, the cliquepartitioning which is returned by SCIPcalcCliquePartition() contains now integer != 0, negatives ones
6713 indicates a negated clique and positive ones indicates a normal clique
6714 - SCIP is now able to detect in DEBUG-mode whether a constraint or variables which will be added, was also created in
6715 the same scip instance, if not an error is thrown
6716 - cons_knapsack is now able to detect negated cliques due to negated cliques on knapsack constraints
6717 - SCIP is now able to write non-linear opb-files(linear instances with and-constraints)
6718 - New constraint handlers for linking constraints (only Beta), cumulative constraints, and for breaking orbitopal symmetries
6719 - `negated cliques` handling in knapsack constraint handler got changed due to the new method
6720 SCIPcalcNegatedCliquePartition() resulting in new consdata members `negcliquepartition`, `negcliquepartitioned` and
6721 `nnegcliques`; changed SCIPcalcCliquePartition() so all cliquepartitions (calculated by SCIPcalcCliquePartition() or
6722 SCIPcalcNegatedCliquePartition(), which uses the first one) contain again not negative integers
6723 - `and`, `knapsack`, `linear`, `logic`, `or`, `quadratic`, `setpp`, `varbound`, `xor` and `clique` constraint handlers
6724 can handle implicit binary variables
6725 - knapsack constraint handler is now able to pairwise presolving constraints
6726 - constraint handlers `logicor`, `and`, `or` can parse their output
6727 - constraint handler `or` can copy its constraints
6728 - added packing/partitioning orbitope constraint handler for symmetry handling (cons_orbitope.{c,h})
6729 - added constraint handler for second order cone constraints (cons_soc.(c|h))
6730 - added constraint handler cons_linking.{c,h} (see cons_linking.c for more details)
6731 - cons_quadratic can make solutions in CONSCHECK feasible for the quadratic constraints by moving values of linear
6732 variables and passing the modified solution to the trysol heuristic
6733 - constraint handler can now register their upgrade functions for quadratic constraints to cons_quadratic (similar to
6737 - New separators for oddcycle cuts and Chvatal-Gomory cuts using sub-MIPs
6738 - modified implementation of separation algorithms in cons_knapsack.c according to results of diploma thesis; including
6739 super-additive lifting (disabled)
6740 - uncommented decomposeProblem() in sepa_zerohalf.c (in default settings, not used anyway): was not adapted to the case
6741 that contiuous variables are allowed in a row
6742 - new separator rapid learning (sepa_rapidlearning.{c,h}) that produces conflicts, global bound changes, primal
6743 solutions and initializes inference values for branching
6744 - added Chvatal-Gomory cuts separated with a sub-MIP (sepa_cgmip.{c|h})
6745 - added reader for 'Weigted Boolean Optimization': problems (reader_wbo.{c,h}), this reader needs the reader_opb files
6746 - new separator oddcycle (sepa_oddcycle.{c,h}) separates oddcycle inequalities using the implication/conflict graph and
6747 dijkstra-algorithm based on binary heaps (dijkstra/dijkstra_bh.{c,h})
6750 - Branching on externally given candidates, the \ref BRANCH 'branching rules' have a second new callback method
6751 (see type_branch.h for more details): SCIP_DECL_BRANCHEXECEXT(x) can be used to branch on external branching candidates,
6752 which can be added by a user's `relaxation handler` or `constraint handler` plugin, calling SCIPaddExternBranchCand().
6753 - added branchcands for relaxator solution, that can be added by the relaxator and used by branching rules
6754 - added relaxsol to variables, s.t. a relaxator can store a solution on which branching or separation can be done
6755 - SCIP can now branch on relaxation solutions that are either installed to the relaxsol field of the variables or added
6756 to the list of relaxation candidates, e.g., by constraint handlers. Branching on relaxation solutions is performed if
6757 the enforcement resulted in an unresolved infeasibility and there are no LP branching candidates, but before pseudo
6758 solution branching. The branching rules leastinf, mostinf, random and pscost implement the callback for branching on
6759 relaxation candidates.
6760 - SCIP can branch on continuous variables. The branching value x' must not be one of the bounds. Two children (x <= x',
6761 x >= x') will be created.
6762 - the vbc visualization adds the branching type (lower or upper bound change) and the new bound to the node information
6763 - the vbc visualization adds the new bound of the branched variable to the node information
6766 - added statistic information about the first primal solution to SCIP statistic; in the statistic output a new line
6767 appears with this information
6768 - now the statistic displays the number of calls of the feasibility checking method of each constraint handler and the
6772 - New rounding and propagation heuristics
6773 - New propagator for variable bounds
6774 - primal heuristics may now be called directly after the node's propagation loop, using the new timing point
6775 `SCIP_HEURTIMING_AFTERPROPLOOP`
6776 - following methods SCIPinferVarUbProp(), SCIPinferVarLbProp(), SCIPinferVarLbCons(), SCIPinferVarUbCons() have a new 6th
6777 parameter `SCIP_Bool force` which allows bound tightening even if the difference to the newbound is below bound
6778 strengthening tolerance
6779 - added propagator for variable lower and upper bounds (prop_vbounds.{c,h}); adjusted cons_varbound.c, var.c, and,
6780 implics.c to work correctly with the new propagator
6783 + Improved constraint handler for quadratic constraints
6784 + New constraint handler for second order cone constraints
6785 + New MINLP heuristics (undercover, subnlp)
6786 + Preliminary support for non-linear relaxations (via expression trees)
6787 + Automatic branching on solutions from arbitrary relaxations and on continuous variables
6789Performance improvements
6790------------------------
6792- improved `settings/emphasis/cpsolver.set` to decrease time per node
6793- reworked access to pseudo solution and inference value of variables in order to reduce function calls
6794- changed default value of parameter `nodeselection/restartdfs/selectbestfreq` to 0; this means if the current node has
6795 no children the node with the best bound is selected (SCIPgetBestboundNode())
6796- added a dual reduction step in cons_knapsack.c
6797- fasten check for common cliques in SCIPcliquelistsHaveCommonClique
6798- SCIP with CPLEX as LP solver now uses quickstart steepest edge pricing as default instead of steepest edge pricing
6799- avoid unnecessary domain propagation and LP resolve at nodes with infeasible LP relaxation
6800- improved zerohalf cut separator: more than one delta is tested for MIR cuts, better handling of dense base
6801 inequalities, faster scaling of fractional coefficients in rows (now enabled), improved parameter settings (presolving)
6804 - in root node, first LP solution is checked for feasibility to avoid expensive setup
6805 - avoided restarting if LP solution is feasible
6806 - separators are not called any longer for an integral initial LP solution
6808Examples and applications
6809-------------------------
6811- New branch-and-price example which includes Ryan/Foster branching (binpacking example)
6812- New example illustrating the use of an event handler (`example/Eventhdlr`)
6817- Enhanced user interface for callable library: manual restarts, predefined settings and many other features
6818- Support of wbo format for weighted PBO problems, IBM's xml-solution format and pip format for polynomial mixed-integer programs
6819- Extended reader for Flatzinc models
6820- new API for 'expressions interpreter': code that evaluates expression trees, including first and second derivatives
6821- NLP solver interface (NLPI) now independent of SCIP like LPI
6822- SCIP can now maintain a central NLP relaxation of the problem (similar to LP)
6823- SCIP can now manage a list of external codes (e.g., LP or NLP solver, ZIMPL)
6824- lp.h/lp.c and the lpi's were changed according to the changes mentioned below.
6825- adding and deletion of rows to the separation storage and to the LP can now be catched by events
6826 (`SCIP_EVENTTYPE_ROWADDEDSEPA`, `SCIP_EVENTTYPE_ROWDELETEDSEPA`, `SCIP_EVENTTYPE_ROWADDEDLP`, `SCIP_EVENTTYPE_ROWDELETEDLP`)
6828### New and changed callbacks
6830- new callback SCIP_DECL_BRANCHEXECRELAX(), together with new parameter in SCIPincludeBranchrule() for branching on a
6833- Copying a SCIP instance:
6834 - Constraint handlers have two new callback methods. One for copying the constraint handler plugins
6835 SCIP_DECL_CONSHDLRCOPY() and the other for copying a constraint itself, SCIP_DECL_CONSCOPY().
6836 - All plugins, like \ref BRANCH `branching rules` and \ref HEUR `primal heuristics`, have a new callback method (see, e.g.,
6837 type_branch.h and type_heur.h for more details):
6838 - SCIP_DECL_BRANCHCOPY(x), SCIP_DECL_HEURCOPY(x) etc.
6839 - When copying a SCIP instance, these methods are called to copy the plugins.
6840 - The main problem has a new callback method (see type_prob.h for more details) SCIP_DECL_PROBCOPY(x) when copying a
6841 SCIP instance, this method is called to copy the problem's data.
6842 - Variables have a new callback method (see type_var.h for more details) SCIP_DECL_VARCOPY(x) when copying a SCIP
6843 instance, this method is called to copy the variables' data.
6846 - The callback SCIP_DECL_PROBEXITSOL(x) in the main problem has one new parameter (see type_prob.h for more details):
6847 - The parameter `restart` is `TRUE` if the callback method was triggered by a restart.
6849### Deleted and changed API methods
6851- All C++ objects and constructors have a SCIP pointer, now.
6852- added parameter scip to ObjCloneable::clone()
6853- changes in a row can now be catched via row events (SCIPcatchRowEvent(), SCIPdropRowEvent(),
6854 `SCIP_EVENTTYPE_ROWCOEFCHANGED`, `SCIP_EVENTTYPE_ROWCONSTCHANGED`, `SCIP_EVENTTYPE_ROWSIDECHANGED`)
6855- added new parameter `varcopy` to SCIPcreateVar() to add the function for copying variable data
6856- in case of using SCIPwriteTransProblem() the currently (locally) valid problem is written this now also includes the
6860 - The predefined setting files like `settings/cuts/off.set,aggressive.set,fast.set` have been replaced by
6861 interface methods like SCIPsetHeuristics(), SCIPsetPresolving(), SCIPsetSeparating(), and SCIPsetEmphasis() in
6862 \ref scip.h and by user dialogs in the interactive shell like
6863 `SCIP> set {heuristics|presolving|separating} emphasis {aggressive|fast|off}` or
6864 `SCIP> set emphasis {counter|cpsolver|easycip|feasibility|hardlp|optimality}`
6865 - All functions for setting user parameters of different types like SCIPparamSetBool(), SCIPparamSetChar(),
6866 SCIPparamSetInt(), SCIPparamSetLongint(), and SCIPparamSetString() in pub_paramset.h have a new parameter
6867 `quiet` it prevents any output during the assign to a new value.
6870 - NLPIs can now be used without generating a SCIP instance (i.e., do not require a SCIP pointer), code moved into src/nlpi
6871 - NLPIs can now be managed like other SCIP plugins, i.e., they can be included into the SCIP core and accessed by
6872 methods SCIPincludeNlpi(), SCIPfindNlpi(), SCIPgetNNlpis(), SCIPgetNlpis(), SCIPsetNlpiPriority()
6874- Intervalarithmetic:
6875 - method SCIPgetVarPseudocostCurrentRun() now returns the pseudocost value of one branching direction, scaled to a unit
6876 interval, old method now called SCIPgetVarPseudocostValCurrentRun()
6877 - renamed SCIPintervalScalarProductRealsIntervals()/SCIPintervalScalarProduct() by
6878 SCIPintervalScalprodScalars()/SCIPintervalScalprod() and redesigned them in intervalarith.c including new methods
6879 SCIPintervalScalprodScalarsInf/Sup()
6882 - The usage of strong branching changed. Now, SCIPstartStrongbranch() and SCIPendStrongbranch() must be
6883 called before and after strong branching, respectively.
6884 - The methods SCIPgetVarPseudocost() and SCIPgetVarPseudocostCurrentRun() in \ref scip.h now return the pseudocost value of
6885 one branching direction, scaled to a unit interval. The former versions of SCIPgetVarPseudocost() and
6886 SCIPgetVarPseudocostCurrentRun() are now called SCIPgetVarPseudocostVal() and SCIPgetVarPseudocostValCurrentRun(), respectively.
6887 - The methods SCIPgetVarConflictScore() and SCIPgetVarConflictScoreCurrentRun() in \ref scip.h are now called
6888 SCIPgetVarVSIDS() and SCIPgetVarVSIDSCurrentRun(), respectively.
6889 - The methods SCIPvarGetNInferences(), SCIPvarGetNInferencesCurrentRun(), SCIPvarGetNCutoffs(), and
6890 SCIPvarGetNCutoffsCurrentRun() are now called SCIPvarGetInferenceSum(), SCIPvarGetInferenceSumCurrentRun(),
6891 SCIPvarGetCutoffSum(), and SCIPvarGetCutoffSumCurrentRun(), respectively. Furthermore, they now return
6892 `SCIP_Real` instead of `SCIP_Longint` values.
6893 - The method SCIPgetVarStrongbranch() has been replaced by two methods SCIPgetVarStrongbranchFrac() and
6894 SCIPgetVarStrongbranchInt().
6896- Copying a SCIP instance:
6897 - Every new callback method resulted in a new parameter of the include function for the corresponding plugin,
6898 e.g., SCIPincludeBranchrule() has two new parameters `SCIP_DECL_BRANCHCOPY((*branchcopy))` and
6899 `SCIP_DECL_BRANCHEXECREL((*branchexecrel))`. In the same fashion, the new callbacks
6900 `SCIP_DECL_VARCOPY` and `SCIP_DECL_PROBCOPY` led to new parameters in SCIPcreateVar() and SCIPcreateProb() in
6901 scip.c, respectively.
6902 - W.r.t. to copy and the C++ wrapper classes there are two new classes. These are `ObjCloneable` and `ObjProbCloneable`.
6903 The constraint handlers and variables pricers are derived from `ObjProbCloneable` and all other plugin are derived from `ObjCloneable`.
6904 Both classes implement the function `iscloneable()` which return whether a plugin is clone able or not. Besides that each class has a
6905 function named `clone()` which differ in their signature. See objcloneable.h, objprobcloneable.h, and the TSP example for more details.
6906 - SCIPincludeHeur() and SCIPincludeSepa() in \ref scip.h, as well as scip::ObjSepa() and scip::ObjHeur(), have a new parameter:
6907 `usessubscip`: It can be used to inform SCIP that the heuristic/separator to be included uses a secondary SCIP instance.
6908 - The argument success in `SCIP_DECL_CONSCOPY` has been renamed to valid.
6911 - SCIPcutGenerationHeuristicCmir() in sepa_cmir.h has three new parameters:
6912 - `maxmksetcoefs`: If the mixed knapsack constraint obtained after aggregating LP rows contains more
6913 than `maxmksetcoefs` nonzero coefficients the generation of the c-MIR cut is aborted.
6914 - `delta`: It can be used to obtain the scaling factor which leads to the best c-MIR cut found within
6915 the cut generation heuristic. If a `NULL` pointer is passed, the corresponding c-MIR cut will already be
6916 added to SCIP by SCIPcutGenerationHeuristicCmir(). Otherwise, the user can generate the cut and add it to SCIP
6917 on demand afterwards.
6918 - `deltavalid`: In case, the user wants to know the best scaling factor, i.e., `delta` passed is not `NULL`,
6919 `deltavalid` will be `TRUE` if the stored scaling factor `delta` will lead to a violated c-MIR cut.
6921### New API functions
6923- added SCIPcalcNegatedCliquePartition() to scip.c to calculate a clique partition on negations of all given binary
6925- SCIPpermuteArray() that randomly shuffles an array using the Fisher-Yates algorithm
6926- SCIPgetRandomSubset() that draws a random subset of disjoint elements from a given set of disjoint elements
6928- SCIPlpiGetSolverDesc() to get a descriptive string of an LP solver (developer, webpage, ...)
6929- SCIPholelistGetNext() to get the next hole of the hole list
6930- SCIPlpRecalculateObjSqrNorm() which is used when the old calculated square norm was unreliable
6931- SCIPpricerIsDelayed() which returns if the pricer is delayed (see pub_pricer.h)
6934 - SCIPvarIsBinary() which checks if a variable is (implicit) binary (see var.c for more details)
6935 - SCIPvarGetHolelistOriginal(), SCIPvarGetHolelistGlobal(), SCIPvarGetHolelistLocal() to get the original, global and local holes, respectively
6936 - SCIPvarGetProbvarHole() to tranform a given domain hole to the corresponding active, fixed, or multi-aggregated variable
6939 - allow user to trigger a restart during presolving SCIPrestartSolve()
6940 - SCIPrestartSolve() that allows the user to manually restart the solving process
6941 - SCIPisInRestart() to detect whether we are currently restarting
6944 - for heuristics SCIPheurSetFreq() to change the frequency of the heuristic (pub_heur.h, heur.c)
6945 - SCIPsepaUsesSubscip(), SCIPheurUsesSubscip()
6947- Intervalarithmetic:
6948 - SCIPeventGetHoleLeft() and SCIPeventGetHoleRight() for accessing the left right interval bound of a domain hole added or removed event
6949 - SCIPholelistGetLeft() and SCIPholelistGetRight()to get the left and right interval bounds of the open hole interval
6950 - SCIPintervalAddInf/Sup/Vectors(), SCIPintervalMulInf/Sup() in intervalarith.c
6953 - added SCIPsortPtrPtrLongIntInt(), SCIPsortLongPtrPtrIntInt() and corresponding sorting/inserting/deleting methods in
6954 pub_misc.h and necessary defines in misc.c
6955 - added SCIPsortLongPtrInt() and corresponding sorting/inserting/deleting methods in pub_misc.h and necessary defines in misc.c
6956 - added SCIPsortPtrPtrInt() (and various other) and corresponding sorting/inserting/deleting methods in pub_misc.h and
6957 necessary defines in misc.c
6958 - SCIPsortPtrBool() and corresponding sorting/inserting/deleting methods in pub_misc.h and necessary defines in misc.c
6960- Constraint Handlers:
6961 - SCIPconshdlrGetEnfoConss(), SCIPconshdlrGetNEnfoConss()
6962 - can now forbid upgrading of individual linear constraints (SCIPmarkDoNotUpgradeConsLinear())
6963 - SCIPpermuteProb() that randomly permutes constraints and variables
6964 - SCIPgetResultantOr() which returns the resultant of an `or` constraint
6965 - SCIPmarkDoNotUpgradeConsLinear() in cons_linear.?, which allows to forbid upgrading of linear constraints
6966 - SCIPgetNUpgrConss() which returns the number of upgraded constraints
6967 - SCIPconshdlrGetCheckTime() and SCIPconshdlrGetNCheckCalls() which returns the running time in the feasibility checking of the
6968 corresponding constraint handler respectively the number of calls of the checking method (implemented in cons.c)
6971 - SCIPcopy() to clone a SCIP instance
6972 - SCIPcopyPlugins(), SCIPcopyParamSettings(), SCIPcopyVars(), SCIPcopyConss(), SCIPgetVarCopy() to copy
6973 individual parts of a SCIP instance separately.
6974 - SCIPcopyProbData() and SCIPprobCopyProbData() which copies the probdata from a sourcescip to a targetscip
6977 - two new functions SCIPgetVarsStrongbranchesFrac()/SCIPgetVarsStrongbranchesInt() for computing strong branching
6978 information for several variables
6979 - SCIPbranchruleGetNRelaxCalls() to get the total number of times, a particular branching rule was called on a relaxation solutions
6980 - SCIPbranchRelax() to branch on a relaxation solution
6981 - SCIPbranchVarVal() to branch on an arbitrary value within the variable's bounds
6982 - SCIPbranchGetBranchingPoint() and SCIPgetBranchingPoint() to select branching point for a variable, e.g.,
6983 ensure branching point is inside the interval for a continuous variable
6984 - SCIPexecRelpscostBranching() in branch_relpscost.{c,h}; this method allows of calling the reliability
6985 pseudo cost branching algorithm for given set of branching candidates from the outside
6986 - SCIPinitVarBranchStats() to initialize the branching statistics (such as pseudo costs, VSIDS, inference values) of a variable
6987 - SCIPselectBranchVarPscost() in branch_pscost.{c,h}; this method selects from a given candidate array a
6988 branching variable w.r.t. pseudo cost branching for relax candidates
6990- Reading, Writing and Parsing:
6991 - SCIPparseVarName() which parses a string in cip-format as a variable name
6992 - SCIPparseVarList() which parses a string as a variable list in cip-format
6993 - the Flatzinc reader can now handle the output annotations of the Flatzinc format; the method SCIPprintSolReaderFzn()
6994 outputs the given solution in Flatzinc format w.r.t. the output annotations
6995 - SCIPprintSolReaderFzn() which prints the best solution in Flatzinc format w.r.t. to the output annotations
6996 in the input file of the flatzinc model
6997 - SCIPwriteVarName() which writes a variable in cip-format to given stream
6998 - SCIPwriteVarsList() which writes an array of variables in cip-Format to given stream
6999 - SCIPwriteVarsLinearsum() which writes an array of variables and coefficients as linear sum in cip-Format to given stream
7001- Copying a SCIP instance:
7002 - SCIPapplyRens() in \ref heur_rens.h has a new parameter `uselprows`. It can be used to switch from LP rows
7003 to SCIP constraints as basis of the sub-SCIP constructed in the RENS heuristic.
7006 - SCIPsetParamsCountsols() which sets the parameter for a valid counting process
7007 - SCIPsetEmphasis() which sets parameter to detect feasibility fast, handle hard LP, solves easy CIPs fast, behaves like a
7008 CP solver, set parameter for a valid counting process; the desired behavior is triggered via a parameter of the function
7009 - SCIPresetParam() to reset the value of a single parameter to its default value
7012 - added SCIPsortRealRealRealPtr() and corresponding sorting/inserting/deleting methods in pub_misc.h and necessary defines in misc.c
7013 as basis for the subSCIP, setting ist to TRUE (uses LP rows) will lead to same version as before
7014 - SCIPsetHeuristics(), SCIPsetSeparating(), SCIPsetPresolving() which set the heuristics to aggressive, fast, off, or
7015 default settings, depending on the `SCIP_PARAMSET` parameter
7016 - SCIPsetSubscipsOff() which disables all plugins that uses subscips
7017 - SCIPsepaSetFreq() to set the calling frequency of a separator
7019### Command line interface
7021- added new dialog for setting the SCIP parameters for hardlp, optimality, easy CIP, CP like search
7022- added new dialog for setting the SCIP parameters for feasibility problems `SCIP> set emphasis feasibility`
7023- added new dialog for setting the SCIP parameters for counting `SCIP> set emphasis counting`
7024- added new dialog for setting presolving to aggressive, fast, or off in interactive shell
7025- added new dialog for setting separation to aggressive, fast, or off in interactive shell
7026- added new dialog for writing all solutions which are collected during the counting process (see cons_countsols.{c,h})
7027- added new dialog for setting heuristics to aggressive, fast, or off in interactive shell
7028- added new dialog `display pricers` which displays all included pricers
7030### Interfaces to external software
7032- added interface to CppAD (nlpi/exprinterpret_cppad.cpp)
7033- Improved Xpress, CPLEX, SoPlex interfaces
7034- the SoPlex interface now includes equilibrium scaling on lp's solved from scratch without starting basis
7035- the SoPlex interface can now double check each SoPlex result against CPLEX (lpi_spx.cpp)
7036- the SoPlex interface has the option to restore basis only after entire strong branching phase instead of after each
7037 strong branch (off, because it mostly appears to increase strong branching time and iterations) (lpi_spx.cpp)
7039### Changed parameters
7041- removed parameter `constraints/knapsack/maxnumcardlift` and adapted setting files
7042- changed parameter `lp/fastmip` from boolean to integer, possible values are 0 (off), 1 (medium, default), 2 (full,
7043 must not be used with branch-and-price).
7047- `branching/clamp` to set the minimal fractional distance of a branching point to a continuous variable' bounds
7048- `branching/random/seed` to change the initial seed value of the branching rule random
7049- `constraints/indicator/addCouplingCons` that allows to add variable upper bounds if addCoupling is true
7050- `constraints/indicator/enforceCuts` that allows to check for violated cust in enforcement
7051- `constraints/indicator/maxCouplingValue` for the maximal value of the coefficient in a coupling inequality/constraint
7052- `constraints/indicator/noLinconsCon` which controls whether the linear constraint is not explicitly
7053 added to the problem. default is FALSE
7054- `constraints/knapsack/dualpresolving` to switch dualpresolving on/off inside the knapsack constraint handler, default is TRUE
7055- `constraints/knapsack/presolpairwise` that allows pairwise presolving of knapsack constraints, default is TRUE
7056- `constraints/knapsack/presolusehashing` that allows fast pairwise presolving of knapsack constraints, default is TRUE
7057- `heuristics/crossover/dontwaitatroot` that allows to call crossover at root node independently from nwaitingnodes
7058- `heuristics/rens/uselprows` that allows to switch between LP row and SCIP constraints as basis for the
7059 subSCIP, default is TRUE (uses LP rows)
7060- `lp/rowrepswitch` telling simplex solver to switch to row representation of the basis (if possible),
7061 if number of rows divided by number of columns exceeds this value (default value infinity, i.e. never switch)
7062- `lp/threads` to change the number of threads used to solve the LP relaxation (default is 0: automatic)
7063- `misc/lexdualstalling` that turns on the lex dual algorithm if the separation process is stalling
7064- `misc/usevartable` and `misc/useconstable` which turns on/off the usage of hashtables mapping from
7065 variable/constraint names to the variables/constraints; when turned off, SCIPfindVar() and SCIPfindCons() may not be
7066 used; the hashtables can be turned off for subMIPs to improve the performance, default value TRUE
7067- `misc/usesmalltables` which results in using smaller tables for names, cliques and cuts and improves
7068 the performace for smaller instances, default value FALSE
7069- `misc/permutationseed` to change the permutation seed value for permuting the problem after the
7070 problem is transformed (-1 means no permutation)
7071- `reading/zplreader/usestartsol` which allows to switch ZIMPL start solutions off, default value TRUE
7072- `vbc/dispsols` to propose if the nodes where solutions are found should be visualized in the branch and bound tree
7076- implemented the data structure and events for global and local domain holes added and removed
7077- new data structures and methods to handle nonlinear expressions in NLPI ({type_, struct_, pub_}expression.{h,c}):
7078 nlpioracle can store and evaluate general NLPs now, nlpi_ipopt can solve general NLPs now
7083- minor changes on several evaluation scripts (new statuses: better, solved, sollimit, gaplimit) and short-mode for cmpres.awk
7084- support for FreeBSD (32- and 64-bit) including minor changes in several scripts in the check-directory
7091- added scripts check_*.sh, evalcheck_*.sh and check_*.awk for blis, glkp, gurobi and symphony (including targets in
7092 Makefile) and slightly modified scripts for cplex, cbc and mosek and cmpres-script
7093- added target `lintfiles` which allows to call flexelint with a list of file, for example, make lintfiles
7094 `FILES=src/scip/prop_vbounds.c`
7095- the NLP solver interfaces and expression interpreter are located in a separate library (libnlpi.*; similar to the lpi
7096 library) and is required to link against the SCIP library also projects that use SCIP via `make/make.project` need to
7097 change their Makefile (!!!): in the $(MAINFILE) target, add $(NLPILIBFILE) behind $(LPILIBFILE) in the dependencies
7098 and add $(LINKCXX_l)$(NLPILIB)$(LINKLIBSUFFIX) to the linker flags
7099- The additional NLPI library requires a change in the Makefile of SCIP's project:
7100 The $(MAINFILE) target now has $(NLPILIBFILE) as additional dependency and the linking
7101 command requires $(LINKCXX_l)$(NLPILIB)$(LINKLIBSUFFIX) as additional argument.
7102- A bug in the Makefiles of older versions of the SCIP examples may cause
7103 data loss. If you have a custom Makefile, please ensure that the target
7104 `clean` is changed as described here:
7105 http://scipopt.org/download/bugfixes/scip-1.2.0/make.txt.
7110- fixed bug in conflict.c in the method conflictsetAddBound()
7111- fixed `bug` in projects Makefiles w.r.t. `make clean`
7112- fixed bug in rapid learning with wrong ordering of dual and primal bound update, primal bound is now updated inside
7114- fixed potential bug in rapid learning with dual reductions
7115- fixed potential bug where SCIPselectSimpleValue() returns a value slightly outside of the given bounds due to rounding
7116 errors (probably cancelation in subtraction in SCIPfindSimpleRational), now use rounding control and check result
7117- fixed bug that SCIP could not be continued after it has been stopped due to a limit
7118- fixed bug in var.c: SCIPvarChgLbOriginal() and SCIPvarChgUbOriginal() cannot access original bounds if the variable is
7120- fixed potential bug with pseudo solution branching on free variables
7121- fixed bug with multiaggregations whose infimum and supremum are both infinite: in such a case multiaggregation is now
7123- fixed numerical issue with multiaggregations which are infinite in one direction: value of multiaggregated variable
7124 could have been larger then inifinity
7125- fixed bug w.r.t. of adding a variable bound variable to its self
7126- fixed bug concering the incorrect assumption that every solution computed in SCIPlpGetUnboundedSol() is integral (we
7127 will not branch but return `infeasible or unbounded` like in presolving)
7128- fixed bug while breaking an clique down to their impications (in SCIPcliquetableCleanup() in implics.c) where the
7129 variable was not of vartype `SCIP_VARTYPE_BINARY`, instead of adding an implication we add a variable bound
7130- fixed bug with debugging a solution: during restarts erroneously it was claimed that the primal solution is cut off
7133 - fixed bug w.r.t. ObjDialog and displaying the description of the dialog
7134 - fixed bug when aborting pricing with Ctrl-C
7137 - fixed bug in scip.c w.r.t. to call of conflict analysis for LPs which reached the objective limit in case of diving
7138 - fixed bug with resolving LPs at infeasible root node
7139 - fixed bug in lp.c: in sumMIRRow() rowtoolong was not set correctly
7140 - fixed bug in lp.c w.r.t. objective limit reached and the chosen comparison (fixed buglist entry 40)
7141 - fixed bug in lp.c: if in SCIPlpSolveAndEval() the LP has to be solved from scratch due to numerical troubles, reset
7142 `SCIP_LPPARAM_FROMSCRATCH` to `FALSE` afterwards
7143 - fixed bug in lp.c SCIProwGetObjParallelism() due to a wrong parallelism value which arised from cancellations during
7144 calculation of squared euclidean norm of objective function vector of column variables
7145 - fixed bug in lp.c: SCIPlpGetUnboundedSol() did not ensure that unbounded solution lies withing the bounds of the
7147 - fixed bug in lp.c w.r.t. to the number of `active` pricer
7150 - fixed bug in solve.c where relaxation branching candidates were cleared, but the relaxation was still marked solved
7151 and not called again, furthermore, adjusted criterions for solving a relaxation again
7152 - fixed bugs in solve.c: even with LP solving disabled, the root LP was solved in case continous variables are
7153 contained; setting pricing/maxvars(root) to 1 resulted in not calling the pricers
7154 - fixed bug in solve.c: make sure SCIP terminates correctly also when a user interrupt or gap limit is reached, i.e.,
7155 avoid error `pricing was aborted, but no branching could be created!`
7158 - fixed bug in tree.c: if an explicit branching point is given, we may not recompute a better centering point
7159 - fixed bug in tree.c: propagate implications on multi-aggregated should not be performed
7162 - corrected several asserts in linear and quadratic constraint handler concerning parsing of CIP format
7163 - fixed bug while deleting redundant variables, which have no influence on changing the feasibility of the linear
7164 constraints, we need to update the sides of the constraint at each step, bug number 51 in bugzilla
7165 - fixed bug in copy procedure of AND constraint handler, negated variables have been copied to their originals
7166 - fixed bug when deleting a constraint where the update was delayed and not processed yet (in cons.c)
7167 - fixed bug in cons_linear.c: binary variables should not be multi-aggregated
7168 - fixed bug in cons_quadratic.c: curvature of bivariate quadratic constraints was not detected correctly
7169 - fixed bug in cons_sos2.c: the branching position was sometimes mistakenly increased
7170 - fixed bug in propagation of cons_sos2.c: the node can be cut off at more places: the previous version was not
7171 sucessfull in this respect
7172 - fixed bug in cons_linear.c:applyFixings() which could lead to lhs/rhs smaller/larger than -/+infinity
7173 - fixed bug in cons_linear.c in detectRedundantConstraints() and corrected old bug fix in SCIProwCreate(): we want lhs
7174 <= rhs to be satisfied without numerical tolerances in order to avoid numerical problems in the LP solver
7176- Knapsack Constraint Handler:
7177 - fixed bug in cons_knapsack.c: mergeMultiples() now detects whether a node can be cut off
7178 - fixed bug in cons_knapsack.c w.r.t. to items with zero weight
7179 - fixed bug in cons_knapsack.c: In SCIPseparateRelaxedKnapsack() not all variables need to be active in deeper regions
7181 - fixed bug in cons_knapsack.c and sepa_clique.c: the assumption that implications are always nonredundant and contain
7182 only active variables is not correct anymore as the corresponing vbound might be missing because of numerics
7184- Separation and Cuts:
7185 - fixed bug in cutpool.c: the hashkey computation was not constant over time
7186 - fixed bug in cutpool.c: hashkey of a row changed during the solving process (if a row is made integral after creation,
7187 maxabsval can be invalid when adding it to the pool, but might be recomputed later on)
7188 - fixed bug in sepa_rapidlearning.c, stop processing if there are no binary variables left
7189 - fixed bug in sepa_rapidlearning.c, corrected computation of right dualbound
7190 - fixed bugs in sepa_zerohalf.c, e.g., handling of intscaling and substitution of variable bounds
7191 - fixed bug in sepastore.c in sepastoreApplyLb/Ub being to hard on feasibility decisions
7192 - fixed bug in sepa_flowcover.c: numerical issues while computing candidate set for lambda
7195 - fixed bug in SoPlex autopricing due to which autopricing had behaved like steepest edge pricing so far
7196 - fixed bug in lpi_clp.cpp: SCIPlpiChgBounds() checks if the column status exists in Clp before using it
7197 - fixed wrong assert in Cplex LPI: Due to numerical inaccuracies, a few pivots might be performed after refactorization
7198 - fixed bug concerning assert(!SCIPlpDivingObjChanged(lp)) which was caused by wrong infinity double parameters for
7200 - fixed makefile system for `OSTYPE=darwin` w.r.t. to CPLEX as LP solver
7203 - fixed bug in cons_setppc: aggregated variables were not correctly removed in presolving
7204 - fixed bug in presolving of linear constraint handler: in redundancy detection, two different numerical epsilons were used
7205 - fixed bug in presolving while not applying a bound change on a variable in a single-variable constraint (e.g. x1 =
7206 0.03) in cons_linear which is too small, that lead to another bound change in presol_trivial which is not allowed, so
7207 now this bound change will be forced
7208 - fixed SCIPvarIsTransformedOrigvar() in var.c (variables generated by presol_inttobinary returned false)
7209 - fixed bug w.r.t. an assert in presol_inttobinary.c; it was assumed that the aggregation which is performed there will
7210 never lead to an infeasibility, this is not true, see comment in presol_inttobinary.c
7211 - fixed bug in presol_trivial.c trying to fix continuous variables, now uses a less stricter comparison to fix variables
7212 - fixed bug in cons_bounddisjunction.c: presolve may have tried to tighten bounds on a multiaggregated variable (now
7213 upgrades to linear constraint)
7215- Reading, Writing and Messages:
7216 - fixed bug while trying to write a MIP where SCIP needs to flush the lp changes first
7217 - fixed potential resource leak when running out of memory while writing files
7218 - fixed bug in reader_zpl.c which appeared using the parameter `reading/zplreader/parameters`
7219 - fixed bugs in flatzinc readers with constraints that exclusively consist of constants
7220 - fixed bug in reader_gms: correct handling of nonstandard bounds on general integer variables
7221 - fixed buglist entry 35, which was caused by a wrong read in correction when the reading buffer was full in
7223 - fixed bugs in reader_fzn.c w.r.t. parsing and solution output in Flatzinc format
7224 - fixed bug in reader_fzn.c w.r.t. comment lines
7225 - fixed bug in reader_opb.c w.r.t. comment lines
7226 - fixed bug in message handler w.r.t. to messages which are longer then `SCIP_MAXSTRLEN`
7229 - fixed bugs do to `HEUR_TIMING SCIP_HEURTIMING_AFTERPROPLOOP` which appeared during repropagation
7230 - fixed bug in trivial heuristic: the locking solution might have falsely initialized some values to zero
7231 - fixed bug in heur_oneopt.c w.r.t. to SCIPtrySol(); it is necessary that the bound of the solution is check otherwise,
7232 infeasible solution could be accepted as feasible
7233 - fixed bug in heur_trivial.c w.r.t. to debug messages after a solution was freed
7234 - fixed bug for `HEUR_TIMING SCIP_HEURTIMING_BEFOREPRESOL` and modifiable constraints
7235 - corrected wrong assert in DINS heuristic when called for an empty problem
7236 - fixed potential bug in OCTANE heuristic with nonbasic solutions
7237 - fixed bug in sub-MIP heuristics with parameter change if some default plugins are not included
7238 - fixed bug in trivial heuristic with bounds that are greater than the heuristic's infinity value
7243- As the interface contains several additional callback functions and
7244 parameters for plugins, some effort may be required to compile your
7245 own projects with SCIP 2.0. See also `Changes between version 1.2 and 2.0` in the doxygen
7246 documentation for additional information.
7248@page RN1_2 Release notes for SCIP 1.2
7250@section RN120 SCIP 1.2.0
7251*************************
7256- adjusted hard memory limit to (soft memory limit)*1.1 + 100mb in check.sh, checkcount.sh, check_cplex.sh,
7257 check_cluster.sh and check_cbc.sh
7258- new presolving step in cons_knapsack.c, same like `simplifyinequalities` in cons_linear.c
7259- now it's possible to write strings with more than `SCIP_MAXSTRLEN` amount of characters in all message.c functions
7260- the current/root lp can be marked to be no relaxation of the current/root problem
7261- added new preprocessing step (mergeMultiples) in cons_setppc.c where equal variables are merged
7262- Black-box lexicographic dual simplex algorithm; can now run lexicographical dual algorithm (parameter `lp/lexdualalgo`)
7265 - SCIP now has `lazy bounds`, which are useful for column generation: see @ref PRICER_REMARKS `pricer remarks` for an explanation.
7266 Each variable has now two additional `SCIP_Real` parameter which define a lazy lower and upper bound; lazy means that
7267 there exists constraints which implies these (lazy) bounds. If the lazy lower or upper bound is greater or less than
7268 the local lower or upper bound, respectively, then the corresponding bound is not put into the LP. The bounds are set
7269 to minus and plus infinity per default which yields the same behavior as before. With the methods SCIPchgVarLbLazy()
7270 and SCIPchgVarUbLazy() these bounds can be set. This is of interest if SCIP gets used as a branch-and-price
7271 framework. Attention! The lazy bounds need to be valid for each feasible LP solution. If the objective function
7272 implies bounds on the variables for each optimal LP solution, but these bounds may be violated for arbitrary LP
7273 solutions, these bounds must not be declared lazy!
7274 - interval arithmetic functions can work with unbounded intervals added new functions to allow more operations on
7275 intervals, including solving quadratic interval equations
7278 - extended hybrid relpscost branching rule by usage of the average length of conflicts a variable appears in
7279 - `early branching`-functionality added: in a branch-and-price code, the user can stop pricing at a node although there
7280 may exist variables with negative reduced costs. In this case, the lp-lowerbound will not be used. The pricer has,
7281 however, the option to return a lower bound. This can be useful for column generation.
7284 - Copy constructors and i/o functionality for constraints: all linear type constraint handlers are able to copy
7285 constraints using the function SCIPgetConsCopy() in scip.h
7286 - the linear constraint handler is able to parse a string in CIP format and create a corresponding linear constraint
7287 - Constraint handler for indicator constraints and parsing them from *.lp and *.zpl files
7288 - the indicator constraint can now try to produce a feasible solution (via heur_trysol)
7289 - one can now write indicator constraints in LP-format
7290 - added constraint handler for quadratic constraints
7293 - added new version of zerohalf cuts from Manuel Kutschka
7294 - added multi-commodity-flow cut separator
7297 - Heuristics which are applied before root LP
7298 - added heuristic that performs a local search in an NLP (takes only linear and quadratic constraints into account so far)
7299 - added heuristic that gets a solution from other components and tries it (heur_trysol.?)
7300 - new trivial heuristic: tries zero solution, lower and upper bound solution and some variable lock based fixing
7301 - added new timing point, `SCIP_HEURTIMING_DURINGPRICINGLOOP`, for calling heuristics; If this timing point is used the
7302 corresponding heuristics is called during the pricing loop of variables; we also added this timing point to
7303 heur_simplerounding.{h,c} which has the effect that a LP solution which satisfies all integrality conditions during
7304 the pricing loop is detected
7307 - added first version of an interface to NLP solvers (type_nlpi.h, struct_nlpi.h, nlpi.h, nlpi.c, nlpi_oracle.h, nlpi_oracle.c)
7308 - Preliminary support of non-convex MIQCPs: Constraint handler for quadratic constraints, NLP heuristic and
7309 Ipopt interface, see \ref cons_quadratic.h.
7310 - There are LP-interfaces to QSopt and Gurobi (rudimentary).
7313 - added reader and writer for FlatZinc models (reader_fzn.{c,h})
7314 - added writer for GAMS models (reader_gms.{c,h})
7316Performance improvements
7317------------------------
7319- Enhanced MCF cuts: stable version, used by default
7320- replaced some function calls in loop conditions
7321- in sepa_cmir.c, if mksetcoefs is invalid for delta=1 no other values of delta are tested anymore
7322- changed the timing of the feasibility pump in case of pricing
7323- removed changing of update rule to `ETA` from standard soplex update `Forrest-Tomlin` in lpi_spx.cpp
7324- improved memory usage in heur_octane.c
7325- improved reading time of opb-files, due to using a hashtable for all `and`-constraints
7326- improved performance of merging variables in mergeMultiples() in cons_knapsack.c
7327- improved performance in tightenWeightsLift() and SCIPseparateRelaxedKnapsack() in cons_knapsack.c, due to now
7328 sparse-cleaning `global` arrays instead of using BMSclearMemory... functions for cleaning local arrays each time
7329- improved performance in SCIPcliquelistRemoveFromCliques()
7330- improved performance in SCIPcalcCliquePartition()
7331- improved performance in SCIPvarGetActiveRepresentatives() in var.c
7334 - improved pairwise presolving in cons_and.c due to using a hashtable
7335 - improved pairwise presolving in cons_xor.c due to using a hashtable
7340- A significant change for C++ users is that all include files of SCIP
7341 automatically detect C++ mode, i.e., no `extern `C`` is needed anymore.
7342- Reader for Flatzinc and GAMS models
7344### New and changed callbacks
7346- The callback SCIP_DECL_PRICERREDCOST(x) in the \ref PRICER `pricers` has two new parameters:
7347 + A `result` pointer determines whether the pricer guarantees that there exist no more variables. This allows for early branching.
7348 + A pointer for providing a lower bound.
7350- The \ref CONS `constraint handlers` have two new callback methods (see type_cons.h for more details):
7351 + SCIP_DECL_CONSCOPY(x): this method can be used to copy a constraint.
7352 + SCIP_DECL_CONSPARSE(x): this method can be used to parse a constraint in CIP format.
7354### Deleted and changed API methods
7356- SCIPcalcMIR() in scip.h has two new parameter `mksetcoefsvalid` and `sol`. The parameter `mksetcoefsvalid` stores
7357 whether the coefficients of the mixed knapsack set (`mksetcoefs`) computed in SCIPlpCalcMIR() are valid. If the mixed
7358 knapsack constraint obtained after aggregating LP rows is empty or contains too many nonzero elements the generation of the
7359 c-MIR cut is aborted in SCIPlpCalcMIR() and `mksetcoefs` is not valid. The input parameter `sol` can be used to separate a
7360 solution different from the LP solution.
7361- new parameter `set` in SCIPconsSetInitial().
7362- some interval arithmetic method take an additional argument to denote which value stands for infinity in an interval
7365 - SCIPgetVarClosestVlb() and SCIPgetVarClosestVub() in scip.h have a new parameter `sol`. It can be used to obtain the closest
7366 variable bound w.r.t. a solution different from the LP solution.
7367 - new parameters `lowerbound` and `result` in type_pricer.h: lowerbound can save a lower bound computed by the pricer,
7368 result indicates whether the pricer guarantees that there exist no more variables if no variable was found
7370### New API functions
7372- new methods to deactivate a pricer SCIPdeactivatePricer() in scip.c
7373- new methods in pub_misc.h/misc.c to access hash map lists and elements of a hash map list and to clear all entries in a hash map
7374- SCIPsetProbName() to set problem name in scip.h/c (SCIPprobSetName() in prob.h/c)
7377 - SCIPgetTransObjscale() and SCIPgetTransObjoffset() in scip.c
7378 - SCIPaddObjoffset() in scip.h; sets offset of objective function
7379 - SCIPgetOrigObjoffset() in scip.h; returns the objective offset of the original problem
7380 - SCIPgetOrigObjscale() in scip.h; returns the objective scale of the original problem
7383 - detectRedundantConstraints() in cons_xor.c and necessary hash-functions for fast pairwise presolving
7384 - SCIPparseCons() in scip.h; parses constraint information (in cip format) out of a string
7385 - SCIPgetConsCopy() in scip.h; which copies a constraint of the source SCIP
7388 - SCIPisLPRelax() and SCIPisRootLPRelax() in scip.c and scip.h returning whether the current/root LP is a
7389 relaxation of the current/root problem and thus defines a valid lower bound
7390 - SCIPlpSetIsRelax() and SCIPlpSetRootLPIsRelax() in lp.c and lp.h to set the information, whether the lp is a valid relaxation;
7391 this information is per default set to true and constraint be used. The aggregated version has only 2 linear constraints the
7392 default linearization has nvars + 1
7395 - extended the sort template functions in sorttpl.c with a `five` array; now it possible to used this template to sort
7397 - new interface methods SCIPcolSort(), SCIProwSort(), SCIPcolGetIndex()
7398 - added SCIPsortPtrPtrLongInt() and corresponding sorting/inserting/deleting methods in pub_misc.h and necessary defines
7402 - SCIPprintNodeRootPath() in scip.h This method prints all branching decisions on variables from the root to the given node
7403 - SCIPnodeGetParentBranchings(), SCIPnodeGetAncestorBranchings(), SCIPnodeGetAncestorBranchingPath(); These methods return
7404 the set of variable branchings that were performed in the parent node / all ancestor nodes to create a given node
7405 - SCIPchgVarLbLazy() and SCIPchgVarUbLazy() in scip.h; These methods can be used to change the lazy lower or
7406 upper bound of a variable; This might has the consequences that the bounds of the corresponding variable is not in
7407 LP. This is the case if the lazy lower or upper bound is greater or less than the local lower or upper bound, respectively
7408 - SCIPvarGetLbLazy() and SCIPvarGetUbLazy() in pub_var.h; These methods return the lazy lower or upper bound, respectively
7409 - SCIPvarCompareActiveAndNegated() and SCIPvarCompActiveAndNegated() in pub_var.h for comparing variables
7410 negated, active or fixed the same way
7411 - SCIPparseVars() in scip.h; parses variable information (in cip format) out of a string
7412 - SCIPgetNFixedonesSetppc() and SCIPgetNFixedzerosSetppc() in cons_setppc.{h,c}; these methods returns
7413 current (local) number of variables fixed to one/zero in the given setppc constraint
7414 - SCIPgetVarConflictlengthScore(), SCIPgetVarAvgConflictlength(), SCIPgetAvgConflictlengthScore() and their pendants for the current run
7415 - added function SCIPvarsGetProbvarBinary() in pub_var.h; gets active, fixed, or multi-aggregated problem variables of
7416 binary variables and corresponding negated status
7418### Interfaces to external software
7421 - heavily revised Mosek interface
7422 - new interface to QSopt due to Daniel Espinoza
7423 - First version of LP interfaces to Gurobi and QSopt
7424 - Major performance improvements in LP interfaces to Clp, Mosek and SoPlex
7427 - adjusted interface to ZIMPL (reader_zpl.{c,h} for ZIMPL version 2.10; this interface should also work with older ZIMPL versions
7428 - Adjusted interface to Zimpl version 3.0.0
7429 - added first version of an interface to Ipopt (only QCP, no deletion of vars/cons allowed; nlpi_ipopt.(h|c))
7432 - On http://code.google.com/p/python-zibopt/source/checkout you find a beta
7433 version of a python interface to SCIP implemented by Ryan J. O'Neil.
7435### Changed parameters
7437- removed parameter `constraints/and/initiallp` since it is not needed anymore;
7438- set parameter `constraints/and/sepafreq` default value to 1
7439- display character of oneopt heuristic changed to `b`
7443- `branching/relpscost/advanced/conflenscore`, default value 0.001
7444- `constraints/and/aggrlinearization` in cons_and.c, aggregated version of the linearization
7445- `constraints/and/enforcecuts` in cons_and.c, should cuts be separated during LP enforcing?
7446- `constraints/and/presolusehashing` in cons_and.c, should pairwise presolving use hashing?, default TRUE
7447- `constraints/countsols/sollimit` in cons_countsols.c, counting stops, if the given number of solutions were found (-1: no limit)
7448- `constraints/xor/presolusehashing` in cons_xor.c, should pairwise presolving use hashing?, default TRUE
7449- `heuristics/oneopt/duringroot`, default value TRUE
7456- extend Makefile to link against Ipopt if `IPOPT=true` is set
7461- fixed wrong use of pointer in lp.c
7462- fixed bug with array dimension not reset to zero when array is freed in pseudoobj propagator
7463- fixed bug with enforcement of pseudo solutions: if pseudo solution is choosen because LP hit a limit, it has to be
7464 enforced in any case
7465- fixed potential bug in coloring example: SCIPcreateChild() is now given an estimate in terms of the transformed
7466 problem by SCIPgetLocalTransEstimate(), no longer the estimated original problem value. Also clarified this in the
7467 comments for SCIPcreateChild()
7468- fixed compiler warning `warning: dereferencing type-punned pointer will break strict-aliasing rules` which resuts in
7469 scip-crashes with gcc version 4.4.0
7470- adjusted assert in var.c
7471- fixed bug in SCIPvarGetActiveRepresentatives() in var.c
7472- fixed bug with objective limit in lp.c: previously the infinity value of SCIP was used as default - now the value of
7473 LPI is used. In the earlier version in many cases the problems where never infeasible.
7474- added and adjusted some asserts, initialized some values
7475- increased the numerical stability of coefficient tightening for Big M formulations
7476- fixed bug with incorrect pseudo activities when objective of a variable switches sign in linear constraint handler
7477- fixed bug with empty constraints in several writing routines
7478- fixed `GGT-Kaibel-Bug` in var.c, prop_pseudoobj.c and cons_varbound.c that occured while computing new values using
7482 - fixed bug in coefficient tightening with infinite bounds
7483 - fixed bug in solve.c: in case lowerbound >= upperbound, SCIPsolveIsStopped() returned `SCIP_STATUS_GAPLIMIT`
7486 - fixed bug in SCIPsolveNode() concerning the case that the time limit was hit while solving the LP relaxation of a
7487 subproblem which is already an LP (branching on pseudo solution is not possible)
7488 - fixed bug in vbc tools concerning of marking probing nodes
7489 - fixed bug in solve.c with nodes which are marked to be repropagated while enforcement
7492 - fixed possible infinite loop while multiaggregating a variable in var.c
7493 - fixed bug in SCIPgetSolVals() similar to SCIPgetSolVal(): try to get original variables of transformed ones if the
7494 solution lives in original space
7497 - fixed potential bug: restarts are now only done if no active pricers exist
7498 - fixed bug in SCIPlpSolveAndEval(): if fastmip and pricers enabled and objlimit was reached but CPLEX did not perform
7499 the final pivot step in order to exceed the objlimit, do one additional simplex step with pricing strategy steepest
7500 edge, if this doesn't suffice, turn off fastmip temporarily and solve again. Also consider solstat of the new
7502 - fixed bug with invalid pseudo solution (lower bound was always >= 0) when using pricing.
7503 - fixed bug in SCIPfreeProb() in scip.c: all pricers are deactivated now
7506 - now frees debug memory
7507 - fixed bug with exponential complexity for reallocating memory in SCIPvarGetActiveRepresentatives() in var.c
7508 - fixed casting of void* pointers in memory.h for C++, adjusted the same for C in memory.h and due to that adjusted all
7509 header files(set whole files in extern `C`) and cpp-files(removed unnecessary extern `C` lines)
7510 - removed memory leak in connection with freeing branch and bound nodes: focusnode was not freed if both children could
7511 be cut off due to bounding
7513- Reading and Writing:
7514 - corrected bug in reader_lp.c: earlier read bounds were thrown away (implementation was not conforming to standard)
7515 - fixed bug in reader_lp.c with respect to constraint and variable names which start with two or more dots `..`
7516 - fixed bug in all readers w.r.t. SCIPgetProbvarLinearSum()
7517 - fixed bug in reader_mps.c with respect to corrupted files
7518 - fixed bug in reader_mps.c with respect to writing transformed problems
7519 - changed wrong writing of mps files due to constraints without any name
7520 - fixed a bug during reading debug solution file
7521 - fixed bug in case of reading an objective function in opb format with multiple occurrences of the same variable
7522 - fixed bug in case of reading an objective function in lp format with multiple occurrences of the same variable
7523 - fixed a wrong fix of a reading bug, which was in reality a writing bug in MPS format; integer variables in mps format
7524 without bounds are binary variables, if the bound of an integer variable is infinity you have to write this bound
7527 - fixed bug in sepa_cmir.c, sepa_mcf.c and sepa_flowcover.c: sol different to LP solution is now separated
7528 - corrected two asserts in sepa_redcost.c (reduced costs can be negative for fixed variables: qsopt uses this)
7529 - fixed bug in sepa_zerohalf.c; replacement of own sorting functions by template functions was incorrect
7530 - fixed bug in var.c, cons_knapsack.c and sepa_flowcover.c: variable bounds corresponding to implication are not
7531 generated if coefficient is large, variable bounds with large coefficients are ignored for construction of knapsack
7533 - fixed bug in sepa_impliedbound.c concerning redundant implications
7536 - fixed bug in sepa_cmir.c concerning uninitialized mksetcoefs (if MIR-cut generation is aborted because the aggregated
7537 constraint is empty or contains too many nonzero elements mksetcoefs is invalid)
7538 - interrupts optimization process if a node will be cutoff, which allows the solution
7539 - fixed bug in sepa_impliedbounds.c and sepa_intobj.c: if separating a sol, this sol is now also given to SCIPaddCut()
7540 so that the efficacy of the cut is now computed correctly
7541 - fixed bug in solve.c caused by integer overflow due to setting the number of cuts to INT_MAX
7544 - fixed wrong result in check.awk, if infeasible problems are stopped in presolving
7545 - fixed exponential calculation of solution values during check of original solution, therefore changed
7546 SCIPvarGetActiveRepresentatives() in var.c and flattened all multiaggregated vars at the end of presolving in
7548 - fixed bug with wrong abort criterion in presolving
7549 - fixed bug in presol.c caused by not reseting presolver-wasdelayed status
7550 - fixed bug in SCIPconsSetInitial() that occurred in pairwise presolving: add or delete constraint in initconss when
7551 changing the initial flag
7554 - fixed bug in cons.c caused by not resetting conshdlr data after restart
7555 - fixed memory error in cons_countsols.c
7556 - fixed assert in cons_and.c method SCIP_DECL_CONSINITSOL(consInitsolAnd)
7557 - fixed bug in cons_countsols.c we respect to warning message that `The current parameter setting might cause ...`
7559- Knapsack Constraint Handler:
7560 - fixed wrong assert in cons_knapsack.c and handled a special this case in simplifyInequalities()
7561 - fixed some bugs in simplifyInequalities() in cons_knapsack.c
7562 - fixed bug in mergeMultiples() in cons_knapsack.c
7563 - adjusted ConsData and ConsHdlrData in cons_knapsack.c
7564 - fixed compiler warning caused by no initialization of two integer in cons_knapsack.c
7565 - fixed bug in cons_knapsack.c caused by having a multi-aggregated variable in a knapsack constraint, now applyFixing is
7566 able to resolve a binary multi-aggregation with integral values
7568- Linear Constraint Handler:
7569 - fixed infinity loop in simplify inequalities in cons_linear.c
7570 - fixed bug in cons_linear.c: do not select variable as slack variable for multiaggregation in convertLongEquality if it
7571 has been marked as not-multiaggregable
7572 - fixed bug in cons_linear.c: also do not multiaggregate variables in dual preproccessing if it has been marked as
7574 - fixed bug in cons_linear.c: slight decrease of epsilon in order to make sure that scaled coefficients are really
7576 - fixed bug in chgRhs() and chgLhs() of cons_linear.c: after changing lhs or rhs of a constraints lhs <= rhs has to be
7577 satisfied without numerical tolerances
7580 - added and changed some SCIPisStopped() calls in several heuristics
7581 - fixed bug in oneopt heuritic with start solution which has become infeasible due to global bound changes
7584 - corrected several bugs in the Clp-interface concerning return values
7585 - fixed potential interface bug: time limits of 0.0 are not anymore passed to the LP solver, which may have caused
7588@page RN1_1 Release notes for SCIP 1.1
7590@section RN110 SCIP 1.1.0
7591*************************
7596- SCIP can now count integer feasible solutions for IPs/CIPs (without continuous variables) (see SCIPcount())
7597- check.awk now uses TeX package supertabular which supports automatic pagebreak
7598- struct `SCIP_Stat` has now two additional variables: `nprobboundchgs`, `nprobholechgs`; these are used to fix the domain
7599 reduction counts in sepa.c, cons.c, branch.c and prop.c; this means, that now the domain reduction counts are reduced
7600 by those domain reduceds which are preformed during probing
7601- added capabilities to flatten the (multi)-aggregation graph of variables
7602- pseudoobj propagator now also propagates the global lower (dual) bound
7603- new heuristic DINS (distance induced neighborhood search by Ghosh)
7606 - SCIP can now output a picture of the constraint matrix in PPM format.
7607 - output of real values is now done with 15 digits after the decimal point
7608 - Extended the capabilities of SCIP to output problems in different formats (LP, MPS, CIP, ...). You can output the original and
7609 transformed problem. Furthermore, generic names can be given to the variables and constraints.
7610 - The feasibility test for solutions at the end of the execution now outputs more useful information.
7611 This made some changes in the interface of constraint handlers necessary.
7614 - added predefined settings file presolving/aggressive.set
7615 - new presolver boundshift (presol_boundshift.{c,h}); this presolver is currently turned off with default parameter setting
7618 - linear constraint handler now detects continuous variables that are implicit integer in dual presolve
7619 - replaced some old sorting methods in cons_knapsack.c, heur_octane.c, sepa_flowcover.c and presol_probing.c through
7620 SCIPsort...() interfaces, adjusted misc.{c,h} and pub_misc.h for these changes
7621 - cons_countsols.c is now able to store the collected solution if required
7622 - added first version of SOS type 1 constraint handler (cons_sos1.{c,h})
7623 - added first version of SOS type 2 constraint handler (cons_sos2.{c,h})
7624 - less aggressive scaling in linear constraint handler presolve to improve numerics
7625 - added first version of constraint handler cons_countsols.{c,h}
7628 - added ccg-reader (weighted column connectivity graph)
7629 - added reader for pseudo-Boolean problems (reader_opb.{c,h})
7630 - the ZPL reader is now able to pass a starting solution to SCIP
7631 - the MPS reader is now able to write a problem in MPS format
7632 - the ZIMPL reader now understands SOS type 1 and 2 constraints
7633 - the LP reader reads SOS constraints of type 1 and 2
7634 - the MPS reader reads the SOS section (but cannot yet handle `MARKERS`)
7637 - The SoPlex LPI can now write basis files.
7638 - revised lpi_clp.cpp (many small changes, in particular writing and reading of bases)
7639 - added FASTMIP settings in lpi_clp.cpp that try to improve the performance of Clp as much as possible
7641- Cuts and Separation:
7642 - the c-MIR separator now also tries to get rid of implicit integer variables by aggregation
7643 - allow cut selection based on support of inequality in orthogonality computation
7644 - disabled zerohalf cuts by default
7645 - adjusted all predefined settings files, e.g., `settings/cuts/fast.set`, such that they are consistent wrt removed,
7646 added and changed parameter values of scip.
7647 - New cutting plane separator MCF (beta version).
7648 - new separator sepa_zerohalf.{c,h}; separates {0,1/2}-Cuts according to Caprara and Fischetti
7650Performance improvements
7651------------------------
7653- heavily decreased the usage of SCIPisStopped(), which costs system time
7654- small performance improvement of c-MIR aggregation heuristic
7655- reworked strong branching in lpi_clp.cpp (scaling works now, bounds can be trusted)
7658 - The preprocessing has been revised. It now applies bound computations in a numerically more stable way. The pairwise
7659 comparison of linear, logicor, and setppc constraints has been improved.
7660 - better branching in SOS1/SOS2 constraints
7661 - fixed performance bug with large number of unnamed constraints that will kill the name hash table (now, unnamed
7662 constraints are not put into the hash table)
7664- Cuts and Separation:
7665 - improved the performance of SCIPcalcMIR() and SCIPcalcStrongCG() by exploiting sparsity
7666 - improved performance of SCIPvarGetLPSol(), which affects many parts of the code, in particular Gomory and strong CG cuts
7667 - do not calculate MIR and StrongCG cut aggregations if number of nonzeros in aggregated row is too large
7670 - improved pairwise presolving in cons_linear.c: reduced cache misses, reduced number of SCIPisStopped() calls and
7671 included detecting of redundant constraints with hash table in advance
7672 - tighter memory limits in knapsack presolve lifting procedure to avoid overly expensive presolving
7673 - included detecting of redundant constraints with hash table in advance in cons_logicor.c and limit other pairwise
7675 - included detecting of redundant constraints with hash table in advance in cons_setppc.c and limit other pairwise
7677 - limit pairwise presolving in cons_linear.c
7679Examples and applications
7680-------------------------
7682- Added an example for the graph coloring problem in `examples/Coloring`, showing the usage of column generation.
7684- extended TSP example
7689### New and changed callbacks
7691- New callback method SCIP_DECL_READERWRITE(x) in type_reader.h; this method is called to write a problem to file
7692 stream in the format the reader stands for; useful for writing the transformed problem in LP or MPS format. Hence,
7693 also SCIPincludeReader() has changed.
7694- The callback \ref CONSCHECK (SCIP_DECL_CONSCHECK()) in the constraint handlers now has a new parameter `printreason` that tells
7695 a constraint handler to output the reason for a possible infeasibility of the solution to be checked using
7696 SCIPinfoMessage(). Have a look at one of the constraint handlers implemented in SCIP to see how it works. This
7697 methodology makes it possible to output the reason of a violation in human readable form, for instance, for the check
7698 at the end of a SCIP run, where the obtained best solution is checked against the original formulation.\n This change
7699 often has little effect on C-implementations, since this parameter can be safely ignored with respect to the
7700 correctness of the code. The corresponding C++ method scip::ObjConshdlr::scip_check(), however, has to be extended
7701 and will not compile otherwise.
7702- added new LPI pricing option `SCIP_PRICING_LPIDEFAULT`, such that every LP interface can set the default pricing
7703 strategy on its own (`auto` is not useful for this, because for CPLEX, for example, SCIP seems to be worse with `auto`
7704 then with `steepest edge`)
7705- Added user pointer to callback methods of hash table, see pub_misc.h.
7707### Deleted and changed API methods
7709- SCIPgetVarRedcost() now returns 0 for variables that have been aggregated out or removed in presolving.
7710 reduced cost in case of infeasible LPs)
7711- new parameter `maxfrac` for SCIPcalcStrongCG()
7712- new parameter `maxmksetcoefs` for SCIPcalcMIR() and SCIPcalcStrongCG() methods
7713- new parameter `conshdlrname` in SCIPincludeLinconsUpgrade()
7716 - new parameters `extension` in SCIPreadProb() defining a desired file format or `NULL` if file extension should be use
7717 - New parameters `extension` and `genericnames` in SCIPprintTransProblem(), SCIPprintOrigProblem(),
7718 SCIPwriteOrigProblem(), and SCIPwriteTransProblem() defining the requested format or `NULL` for default CIP format
7719 and using generic names for the variables and constraints. Examples are
7720 - SCIPprintTransProblem(scip, NULL, NULL, TRUE) displays the transformed problem in CIP format with
7721 generic variables and constraint names
7722 - SCIPprintOrigProblem(scip, NULL, `lp`, FALSE) displays the original problem in LP format with
7723 original variables and constraint names.
7726 - expand sorttpl.c by some parameters
7727 - changed some names for sorting methods
7728 - replaced sorting methods SCIPbsort...() by faster (quicksort/shellsort) algorithms SCIPsort...() Note that the order
7729 of the parameters has been changed to simplify the template code in sorttpl.c!
7732 - SCIPcheckSolOrig() is restructured. The last two parameters have changed. They are now bools indicating
7733 whether the reason for the violation should be printed to the standard output and whether all violations should be
7734 printed. This reflects the changes in the constraint handlers above, which allow the automation of the feasibility
7735 test. The pointers to store the constraint handler or constraint are not needed anymore.
7736 - the parameter list of the method SCIPcheckCons() (scip.h) has changed; the new advatage is, that SCIP can print the
7737 reason for the violation of a constraint as for as the constraint handler supports that
7738 - the parameter list of the method scip_check() (objconshdlr.h) has an additional parameter `printreason` see for
7739 explanation the previous point
7741### New API functions
7743- LPI now has a function SCIPlpiGetSolverPointer() that returns a solver dependent pointer. This can be used to directly
7744 access the LP solver. This should, of course, only be used by people that know exactly what they are doing.
7745- added capabilities to avoid multi-aggregation of a single variable by setting a corresponding flag (SCIPmarkDoNotMultaggrVar())
7746- SCIPgetProbvarLinearSum()
7747- SCIPgetResultantAnd() which returns the resultant variable of an `and` constraint
7748- SCIPchgChildPrio() to change the node selection priority of the given child
7750- SCIPrepropagateNode() to mark a node for repropagation
7751- SCIPcount() (in cons_countsols.h) for counting all feasible solution of a given CIP
7752- SCIPcreateRootDialog() (in dialog_default.h) which creates a root dialog
7753- SCIPgetVectorEfficacyNorm()
7754- SCIPseparateRelaxedKnapsack() in cons_knapsack.h
7755- SCIPgetCutoffdepth() which returns the depth of first node in active path that is marked being cutoff
7756- SCIPflattenVarAggregationGraph()
7757- SCIPclockGetLastTime()
7758- SCIPcalcHashtableSize() to get a reasonable hash table size
7759- SCIPgetVarFarkasCoef() and SCIPgetColFarkasCoef() to get the farkas coefficient of a variable (analogon of
7760- SCIPgetRepropdepth() to get the depth of first node in active path that has to be propagated again
7761- SCIPmajorVersion(), SCIPminorVersion() and SCIPtechVersion() returning the corresponding version
7763- Read, Write and Print:
7764 - SCIPprintSysError() which encapsulates the strerror_r calls, the NO_STRERROR_R flag switches between the use
7765 of strerror_r and strerror inside
7766 - SCIPsnprintf() safe version of snprintf (and sprintf)
7767 - SCIPreaderCanRead() and SCIPreaderCanWrite() in pub_reader.h, these return TRUE if the corresponding
7768 reader is capable to read or write, respectively
7769 - SCIPwriteOrigProblem(), e.g., SCIPwriteOrigProblem(scip, `orig.lp`, NULL, FALSE) prints the original
7770 problem in LP format in the file `orig.lp`
7771 - SCIPwriteTransProblem(), e.g., SCIPwriteTransProblem(scip, NULL, NULL, FALSE) displays the transformed problem in CIP format
7774 - SCIPcutGenerationHeuristicCmir() in sepa_cmir.h
7775 - SCIPheurGetTimingmask() and SCIPheurSetTimingmask()
7778 - added some downwards-sorting methods
7780 - SCIPsortedvecInsert...(), SCIPsortedvecInsertDown...(), SCIPsortedvecDelPos...(),
7781 SCIPsortedvecDelPosDown...(), SCIPsortedvecFind...() and SCIPsortedvecFindDown...() to manage sorted vectors or
7782 groups of vectors of various data types that are sorted w.r.t. the first vector
7784### Command line interface
7786- advanced reading and writing dialog in interactive shell
7788### Interfaces to external software
7790- Many changes in the SoPlex interface: The current one is tailored towards SoPlex 1.4 (aka 1.3.3). All SoPlex functions
7791 (where applicable) should now have an exception handling. The Bugfix for adding columns has been moved to SoPlex. One
7792 can use ROW representation. Reading/writing of a basis has been implemented.
7794### Changed parameters
7796- changed default frequency parameters for RINS, Local Branching, Crossover and Mutation heuristic This should not
7797 change the performance but happened just for consistency reasons
7798- changed parameter default values for the priority of presolver `dualfix` and `inttobinary`
7799- removed parameter `separating/cmir/maxtestdeltaroot`
7800- new value `l` for parameter `lp/pricing`, which is the new default
7804- `constraints/and/linearize` to enable linearization of all <and> constraints (in presolving),
7805- `constraints/and/initiallp` to turn on, off, or `auto` that the LP relaxation of the AND constraints are in the initial LP;
7806- `constraints/countsols/collect` to enable the storing of the solutions; default value FALSE;
7807- `constraints/indicator/addCoupling` to enable generation of relaxation
7808- `constraints/indicator/branchIndicators` to decide whether it is branched on indicator constraints in enforcing
7809- `constraints/indicator/genLogicor` to decide whether logicor constraints instead of cuts are generated
7810- `constraints/indicator/sepaAlternativeLP` to decide whether separation takes place using the alternative LP
7811- `constraints/linear/aggregatevariables` to search for aggregations in equations in the presolving step
7812- `constraints/linear/dualpresolving` to disable dual presolving step in the linear constraint handler; default value is TRUE
7813- `constraints/linear/simplifyinequalities` to enable a simplification step for inequalities; default value is set to FALSE = disabled
7814- `constraints/linear/upgrade/binpack` to enable or disable the linear upgrading process
7815- `constraints/linear/upgrade/eqknapsack` to enable or disable the linear upgrading process
7816- `constraints/linear/upgrade/invarknapsack` to enable or disable the linear upgrading process
7817- `constraints/linear/upgrade/knapsack` to enable or disable the linear upgrading process
7818- `constraints/linear/upgrade/logicor` to enable or disable the linear upgrading process
7819- `constraints/linear/upgrade/setppc` to enable or disable the linear upgrading process
7820- `constraints/linear/upgrade/varbound` to enable or disable the linear upgrading process
7821- `constraints/linear/presolusehashing` to use hashing comparison in cons_linear.c; default value is TRUE
7822- `constraints/logicor/presolusehashing` to use hashing comparison in cons_logicor.c; default value is TRUE
7823- `constraints/setppc/presolusehashing` to use hashing comparison in cons_setppc.c; default value is TRUE
7824- `constraints/SOS1/branchNonzeros` to decide whether SOS1 constraint with largest number of nonzero variables is picked for branching
7825- `constraints/SOS1/branchSOS` to enable or disable branching on SOS1 constraints
7826- `heuristics/feaspump/beforecuts` to allow the feaspump to be called before cut separation
7827- `heuristics/mutation/minimprove`
7828- `presol/donotmultaggr` which disables multiaggregation for all variables of the problem
7829- `separating/cmir/densityoffset` to allow for more c-MIR cuts on small models
7830- `separating/orthofunc` to choose function for scalar product computation in orthogonality test
7835- updated mmm.{test,solu}, mittelmann.{test,solu}, miplib3.solu, miplib.solu, shortmiplib.test and added
7836 mittelmann_current.test, mittelmann_old.test
7837- added test scripts for testing counting (make testcount)
7838- removed tag make testpre (useless without corresponding scripts)
7839- added tag testcount (make testcount); this allows for testing counting problem
7840- replaced tcsh by bash and gawk by awk in all check scripts to achieve higher compatibility
7847- added `make/make.project` as default make include for external projects using SCIP
7848- added possibility to compile shared libraries in makefiles (and added `make/make.linux.x86.gnu.opt-shared`)
7849- replaced <string> by <cstring> in all C++-interfaces to get `strlen()` included (gcc-4.3 gave an error)
7850- Moved -rpath option for ld to linux-specific Makefiles.
7851- Re-activated readline library on darwin/ppc.
7854 - added in all `make/make.*` `GMP_FLAGS` and `GMP_LDFLAGS`
7855 - new flag GMP with values (`auto`, `true and `false`); in case of `auto` the library gmp is linked if ZIMPL is
7857 - adapted all makefiles of the examples accordingly
7860 - modified makefiles to accept ZIMPLOPT and LPSOPT flags (with values `opt` or `dbg` and default being `opt`), and
7861 removed `LPS=spxdbg` and `LPS=clpdbg`
7862 - added target spx132 for SoPlex version 1.3.2
7867- fixed CTRL-C if NO_SIGACTION is set (e.g., for MinGW)
7868- added checks whether a plugin (handler) has already been included to avoid later complications e.g. with parameters.
7869- fixed bug with wrong `tightened` return value of some of the change bounds methods
7870- forced full propagation in presolving -> this fixes a bug that implied that variable locks became inconsistent
7871- replaced calls to perror() by SCIP error message using strerror(errno); this avoids problems with the error output
7873- fixed bug in method SCIPgetProbvarLinearSum()
7874- fixed bug with errors occurring in sub-MIPs. Search is only aborted in dbg mode, in opt mode a warning will be printed
7875- fixed bug in tclique-graph datastructure concerning insertion of edges into nonempty graph
7876- corrected bug in SCIPtreeBranchVar() (tree.c): several comparison functions needed a `feas`.
7877- fixed bug in SCIPtightenVarLb/Ub() in scip.c concering forcing a bound change (bound improvement is checked now)
7878- improved stage checking for bound computation
7879- fixed usage of command test for string comparison in check-scripts (now compatible with ubuntu)
7880- replaced sprintf and snprintf by SCIPsnprintf() fixed potential bug with overlong strings
7881- corrected bug in the case when soplex threw an exception in autopricing
7882- fixed bug in SCIPvarGetOrigvarSum() concerning the corner case the a negated variable has no parent variable in
7886 - avoid aggregation of implicit integers with fractional aggregation scalars
7887 - fixed bug in aggregateActiveIntVars(): If a < 0, multiply a*x + b*y == c by -1 (algo for finding initial solution does
7888 only work for a > 0).
7889 - avoiding aggregation that removes information about implicitly integer variables (removes bug)
7890 - fixed bug with exponential running times due to complicated recursive multi-aggregation
7891 - corrected bug in var.c occuring during applying boundchanges in varUpdateAggregationBounds method
7894 - fixed bug that a missing CONSTRANS in constraint handler leads to `NULL` pointer as constraint data for the copied
7895 constraints instead of pointer copies of the consdata (as explained in the constraint handler `HowTo`)
7896 - fixed bugs in second part of consdataTightenCoefs(): Removed min/maxleftactisinfinity (definition was not correct),
7897 fixed calculation of min/maxleftactivity and removed asserts concerning whether all redundant vars were deleted (led
7898 to different behavior in debug and opt mod).
7899 - fixed typo in documentation: default value for `dynamic` parameter is FALSE for all constraint handlers!
7900 - fixed bug in preprocessing of SOS2 constraints (cons_sos2.c)
7901 - fixed bug in cons_countsols.c concerning variable locking
7902 - fixed bug in cons_varbounds.c, concerning SCIPaddVarVlb() and SCIPaddVarVub()
7903 - fixed bug in applyFixings() in cons_varbound.c concerning tightening the bound of a variable left in a redundant
7904 constraint (bound change is forced now)
7907 - fixed bug with useless objective cutoff in LNS heuristics
7908 - removed bug for values greater than (-)infinity, heur_shifting.c, heur_intshifting.c, heur_rounding.c, heur_oneopt.c
7909 - fixed bug with errors occurring in heuristic LPs. In opt mode a warning will be printed, abort in dbg mode
7911- Linear Constraints:
7912 - fixed bug with wrong update of activities in linear constraints after global upper bound changes
7913 - fixed bug in preprocessConstraintPairs() in cons_linear.c concerning updating the flags of the constraint that stayes
7914 in the problem (nonredundant information were lost before)
7915 - fixed bug in cons_linear.c caused by comparing two infinity values during checking of using variable as slackvariable
7916 - removed bug for rhs/lhs greater than (-)infinity, cons_linear.c
7917 - removed bug caused by hashcomparison for non-sorted constraints, cons_linear.c
7918 - fixed bugs with wrong presolving due to cancellation in (res-)activities in cons_linear.c
7919 - removed BOUNDSCALETOL adjustment in cons_linear.c. This fixes bug with slightly infeasible variable fixings in
7920 presolving; reliable resactivities should make the BOUNDSCALETOL relaxation redundant.
7921 - removed `epsilontic` bug in cons_linear.c due to adjusting left/right hand side in applyfixing
7922 - fixed bug with multi-aggregated variables in cons_logicor: instead of fixing them, a linear constraint will be created
7923 - corrected bug in cons_linear.c:applyFixings() [if variable was fixed to infinity the rhs/lhs were wrong]
7924 - fixed bugs in pairwise presolving of cons_linear.c concerning deletion of upgraded constraints and inconsistent update
7925 of nchgsides in case of coefsequal and coefsnegated
7926 - fixed false assert and corrected a bug caused by deleting a constraint on `firstchanged` position in pairwise
7927 presolving with hashing in cons_linear.c
7930 - fixed handling of unbounded variables with 0 objective in SCIPlpGetModifiedPseudo[Proved]Objval() (lp.c)
7931 - fixed bug with uncatched LPSOLSTAT after hitting a time or iteration limit
7932 - corrected bug in SCIPlpGetState() if the LP is empty
7933 - fixed bug in SCIPlpSolveAndEval(): added extra simplex step if objlimit reached, fastmip and pricers enabled in order
7934 to get dual solution for pricing.
7935 - weakened two too strong asserts in lp.c concerning the LP result OBJLIMIT
7936 - fixed bug in SCIPlpSolveAndEval(): allow more than one extra simplex step for getting an objlimit exceeding solution
7940 - corrected invalid memory access in tcliqueIsEdge: added check whether node1 has no neighbors (tclique_graph.c)
7941 - removed memory leak detected with the help of coverity in dialog.c
7942 - fixed bug with memory reallocation in SCIPgetProbvarLinearSum()
7943 - tried to fix memory leak in dialog.c occuring from different versions of the readline/history libraries
7944 - removed possible memory leak in objdialog.cpp
7947 - fixed numerical issue in linear constraint propagation: need slightly more aggressive tightening such that probing
7948 does not choose a wrong value for fixing inside an epsilon interval
7949 - fixed numerical bug in dual presolving of linear constraint handler
7950 - avoid fixing variables to infinity in order to get rid of numerical inconsistencies in the original model
7953 - added handling of the case of roundable variables with 0 objective in presol_dualfix.c
7954 - fixed bug with writing the MIP relaxation to a file concerning the objective function; in case the original objective
7955 function is requested, the transformed objective function gets re-transformed (scaling, offset)
7956 - fixed bug with wrong objective sense output for transformed problem. The transformed problem is always a minimization
7958 - fixed bug with objective scaling after restart
7961 - fixed bug with reading empty lines in TSP example
7962 - fixed bug with non-conformal parameter name in reader_ppm
7963 - fixed infinite loop in LP file reader if a line exceeds the character limit
7964 - fixed bug in reader_ppm while appending strings for output file
7965 - fixed some `SCIP_RETCODE` bugs in reader_fix.c, reader_sol.c, reader_sos.c and reader_zpl.c
7966 - fixed docu in type_reader.h
7967 - fixed bug with multi-aggregated variables which are de facto aggregated or fixed after flattening the aggregation tree
7968 - fixed bug with bound changes of variables in modifiable constraints during full dual presolving of linear conshdlr
7969 - increased compiler compatibility for C++ wrapper classed by adding extern `C` in obj*.cpp files and changing strlen
7970 calls to std::strlen
7973 - corrected bug in priceAndCutLoop(): separation was aborted if domain reduction was applied
7974 - fixed bug in sepa_mir.c: size of testeddeltas-array was too small
7975 - corrected imlementation of SCIPlpiGetBasisInd() in lpi_clp.cpp (this fixes the bug that almost no Gomory cuts are
7979 - fixed bugs in sorttpl.c: fixed wrong arraysize in shellsort; in case an has at most one element, then no sorting is
7981 - fixed wrong if condition for function call in sorttpl.c
7982 - fixed obvious bug in linear constraint data sorting. Most part of the code assumed pure index sorting, but in fact, it
7983 was sorted by variable type as first criterion and index as second criterion.
7985@page RN1_0 Release notes for SCIP 1.0
7987@section RN100 SCIP 1.0.0
7988*************************
7993- SCIP now has a couple of specialized settings, all called scip_*.set
7994- SCIP is now compatible to the Exception branch of SoPlex
7995- if possible, objective function is scaled to make objective value integral with gcd 1
7996- slightly modified automatic constraint aging strategy
7997- new C templates disp_xxx.h and dialog_xxx.h and C++ wrapper classes objdisp.h and objdialog.h, respectively
7998- modified reader `sol`, st. files which where created via typing the order of commands `set log *.sol`,
7999 `disp sol var -`, `set log cplex.log` in Cplex can now be read
8000- new dummy LP interface `lpi_none.c`; useful for running SCIP without a LP solver
8003 - modified probing presolver to do multiple cycles if called in subsequent runs
8004 - changed sort algorithm in probing presolver
8007 - new node selection rule `estimate` (best estimate search)
8008 - new node selection rule `hybridestim`
8011 - the doxygen documentation now has HowTo's for all plugin types
8012 - the doxygen documentation now contains a FAQ
8013 - the documentation has now a TAB Modules; there you can find list of available constraint handles, presolvers,
8014 propagators, lpi interfaces, file readers and so on
8017 - time limit is now forwarded to lp solving algorithm
8018 - presolving, cut separation, primal heuristics and strong branching now better respect time limit
8021 - best estimate search is now used in all large neighborhood search heuristics
8022 - new improvement heuristic `oneopt`
8023 - new heuristic `actconsdiving` following an idea of John Chinneck
8025- Separation and Cuts:
8026 - modified cut selection code
8027 - cut conversion into linear constraints after a restart now works better
8028 - added flow cover separator
8029 - gomory cuts are now also separated for integral slack variables
8030 - less aggressive in Gomory cut separation
8031 - strong CG cuts are now also separated for integral slack variables
8033Performance improvements
8034------------------------
8036- greatly improved performance of LP file reader by replacing string copies with pointer copies
8037- removed performance bottleneck with non-bfs based node selectors and large leaf queues at the cost of a small memory
8038 overhead (2 ints per node in the leaf queue); this improves performance quite a bit on instances that take a large
8039 number of branching nodes
8040- improved performance of linear constraint propagation by delaying some floor/ceil calculations
8041- improved performance of clique cut separator
8046### New and changed callbacks
8048- new callback method SCIPdialogFree()
8050### Deleted and changed API methods
8052- slightly modified bound substitution heuristic in SCIPcalcMIR() and SCIPcalcStrongCG()
8053- slightly less conservative in numerics for SCIPmakeRowIntegral()
8054- linear and knapsack constraint handler may now deal with coefficients of value zero
8055- new parameter `maxbounddist` for SCIPincludeSepa() and constructor ObjSepa()
8056- new parameter `restart` for method SCIPfreeSolve()
8057- calling SCIPwriteLP() is now possible in Solved Stage
8058- SCIPwrite{LP,MIP} may no longer be called after solving, since the LP data structures may not be valid
8059- All functions SCIP<datatype>Param() got a new parameter `isadvanced`.
8060 This does not influence the performance of SCIP, but the position of the parameter in the settings menu.
8061 Hence, if you do not care about this, you can assign any value to it.
8062 You should add the corresponding flag to the SCIP<datatype>Param() calls in your own source code.
8065 - modified `SCIP_SUBVERSION` to be a number instead of a string (to be able to use `SCIP_SUBVERSION >= ...`)
8066 - SCIPsubversion() now returns an int instead of a const char*
8069 - new parameter `estimate` for SCIPcreateChild() giving an estimate for value of best feasible solution in the subtree to
8070 be created. One possibility is to use SCIPgetLocalOrigEstimate() for this value.
8071 - removed method SCIPnodeGetPriority()
8072 - removed parameter `lowestboundfirst` from SCIPincludeNodesel()
8075 - removed parameter `branchdir` from SCIPbranchVar()
8076 - new parameters `leftchild`, `eqchild` and `downchild` for SCIPbranchVar()
8077 - SCIPgetVarStrongbranch() now also returns lperror == TRUE if the solving process should be stopped, e.g., because of a
8080- Variable tightening:
8081 - replaced methods SCIPvarGetClosestVlb() and SCIPvarGetClosestVub() from pub_var.h by new methods
8082 SCIPgetVarClosestVlb() and SCIPgetVarClosestVlb() in scip.h
8083 - new parameter `force` for SCIPtightenVarLb() and SCIPtightenVarUb()
8085### New API functions
8089- SCIPgetLocalOrigEstimate() and SCIPgetLocalTransEstimate()
8091- SCIProwIsInGlobalCutpool()
8093- SCIPgetVarRedcost()
8094- SCIPtightenVarLbGlobal() and SCIPtightenVarUbGlobal()
8095- SCIPsepaGetMaxbounddist()
8096- SCIPboundchgGetNewbound(), SCIPboundchgGetVar(), SCIPboundchgGetBoundchgtype(),
8097 SCIPboundchgGetBoundtype(), SCIPboundchgIsRedundant(), SCIPdomchgGetNBoundchgs(), SCIPdomchgGetBoundchg()
8098- SCIPnodeUpdateLowerboundLP()
8099- SCIPcalcNodeselPriority()
8100- SCIPnodeGetEstimate()
8101- SCIPnodeGetDomchg()
8102- SCIPgetRootNode() (in combination with SCIPcutoffNode(), this allows the immediate finishing of the optimization)
8104### Command line interface
8106- default dialog menu now includes the commands `set default` and `display parameters`
8107- added option to write node LP and MIP relaxations to LP file from interactive shell
8109### Changed parameters
8111- parameters are now separated into basic and advanced, the latter ones have been moved to extra submenus
8112- priority parameters are now restricted to be in [INT_MIN/4,INT_MAX/4] to avoid overflow errors in comparison methods
8113- increased priority of `estimate` node selector, such that this is the new default node selector
8114- changed meaning of parameter setting `nodeselection/childsel = l`; old meaning is now called `r`
8115- changed default value of `conflict/maxvarsfac` to 0.1
8116- changed default value of `conflict/useprop` to TRUE
8117- changed default value of `conflict/useinflp` to TRUE
8118- changed default value of `conflict/usepseudo` to TRUE
8119- changed default value of `conflict/maxlploops` to 2
8120- changed default value of `conflict/lpiterations` to 10
8121- changed default value of `conflict/interconss` to -1
8122- changed default value of `conflict/reconvlevels` to -1
8123- changed default value of `conflict/settlelocal` to FALSE
8124- changed default value of `constraints/linear/propfreq` to 1
8125- changed default values of `heuristics/∗diving/backtrack` to TRUE
8126- changed default value of `nodeselection/restartdfs/stdpriority` to 10000
8127- changed default value of `numerics/boundstreps` to 0.05 in order to avoid very long propagation loops on continuous variables
8128- changed default value of `presolving/restartfac` to 0.05
8129- changed default value of `presolving/restartminred` to 0.10
8130- changed default value of `separating/objparalfac` to 0.01 for performance reasons
8131- changed default value of global `separating/maxbounddist` to 1.0
8132- changed default value of `separating/objparalfac` to 0.0001
8136- `conflict/enable` to globally enable or disable conflict analysis
8137- `constraints/linear/maxcardbounddist` and `constraints/knapsack/maxcardbounddist`
8138- `heuristics/∗diving/backtrack` to activate 1-level backtracking for most of the diving heuristics
8139- `heuristics/feaspump/maxstallloops`
8140- `nodeselection/childsel` to control the child selection
8141- `presolving/immrestartfac`
8142- `separating/∗/maxbounddist` to have individual maxbounddist parameters per separator
8143- `separating/clique/backtrackfreq` to speed up clique cut separation in heuristic fashion
8144- `separating/redcost/continuous`
8151- added version numbers to library files (There will be a softlink generated in the lib/ and bin/ directories without
8152 version number that point to the latest compiled version.)
8153- added .exe extension to binaries of MinGW
8154- removed the `.static` extension associated to the LINK variable from the Makefile system (If you want to build
8155 makefiles for shared library generation, use the OPT variable. For example, you could create a makefile
8156 `make/make.linux.x86.gnu.opt-shared` and compile it with `make OPT=opt-shared`.)
8158- Defaults and Options:
8159 - modified the default LP solver to be SoPlex instead of CPLEX
8160 - added `LPS=none` for compiling SCIP without a LP solver
8161 - made `ZIMPL=true` the default; if you do not want to include ZIMPL support, call `make ZIMPL=false`
8166- fixed bug in rowScale() concerning deletion of almost zero coefficients
8167- weakened assert in primal.c in order to avoid numerical troubles
8168- fixed bug with too long variable names
8169- fixed bug with strange user descriptions of plugins
8170- changed position of some asserts to prevent segmentation faults
8171- SCIPgetAvgPseudocostCount() and SCIPgetAvgPseudocostCountCurrentRun() now return the average over all integer
8172 variables instead of all variables, since pseudo costs are not recorded for continuous variables
8173- fixed wrong sorting of plugins with priorities close to INT_MIN or INT_MAX
8174- replaced `line` by `read` in Makefile, since `line` is non-standard
8175- fixed bug with branching rules that produce only one child with no changes to the problem
8176- fixed bug that external relaxator is not reset appropriately for a new problem instance
8177- removed wrong assert in function paramWrite()
8178- fixed bug with uninitialized in check.awk
8179- fixed bug in ZIMPL file reader for multiple occurrences of a single variable in the objective function
8180- fixed bug with deleting variables from the transformed problem that are contained in the implication graph
8181- fixed bug in root reduced cost fixing propagator that leads to an empty domain for a variable as a proof of optimality
8182 of the current incumbent
8183- fixed bug with fractional coefficients of binary variables in cont --> impl int upgrading
8186 - fixed bug with aggregated variables in debug solution test
8187 - now it is possible to add original solutions
8188 - fixed bugs with SCIPgetBestsol() returning `NULL` after a restart with user objective limit
8189 - fixed wrong status code in presence of user objective limit and a feasible solution that is not better than the limit
8192 - fixed bug with wrong bound changes of loose variables
8193 - changed wrong assert in SCIPnodeAddBoundinfer()
8194 - fixed bug in variable bounds search and insertion method
8195 - fixed bug regarding modifying bounds in original problem if negated original variables exist
8196 - fixed bug with multiple pending bound changes on some variable
8199 - fixed bug in integer objective separator with restarts
8200 - fixed bug in integer objective separator with dynamic columns
8203 - fixed bug that cut age was not reset to zero for violated cuts
8204 - fixed bug in SCIPcutpoolAddNewRow() concerning update of minidx and maxidx of added row
8205 - fixed numerical bug in rowScaling of lp.c, which possibly cut off feasible solutions
8206 - significantly improved performance of c-MIR and Gomory cuts by caching closest VLB and VUB info
8209 - fixed numerical buf with slightly different LP optimum after resolving due to probing/diving
8210 - fixed bug in cmir and flowcover separator with variables which are currently not in the LP
8211 - fixed bug with LP size management in probing if column generation is used
8212 - fixed bug in LP file reader with row names identical to section keywords
8213 - fixed potential bugs due to errors in resolving the LP after diving or probing
8214 - fixed potential bugs in SCIPpriceLoop() and priceAndCutLoop(), st. now all LP solution stati are handled appropriately
8215 - fixed potential bug with non-existent LP in SCIPwrite{LP,MIP}
8217- Constraint handler:
8218 - removed wrong assert in bounddisjunction constraint enforcement
8219 - fixed numerical bug in propagator of varbound constraint handler
8220 - fixed bug in variable bound constraint handler with changing bounds on multi-aggregated variables
8221 - fixed bug in linear constraint handler: only tight cuts are transformed into linear constraints after restart
8222 - fixed bug in bounddisjunction constraint handler with propagation of multi-aggregated variables
8223 - fixed bug with numerics in linear constraint handler due to non-representable `BOUNDSCALETOL`
8224 - fixed bug with almost integral multi-aggregation in dual presolve of linear constraint handler
8225 - fixed bug with numerics in update of min/maxactivity in linear constraint handler
8228 - fixed bug in intshifting and oneopt heuristic with variables which are currently not in the LP
8229 - fixed bug with primal heuristics reducing the cutoff bound such that the current node is cut off
8230 - fixed bug in oneopt heuristic: must not be called on pseudo nodes if continuous variables are present
8232@page RN0_9 Release notes for SCIP 0.9
8234@section RN090 SCIP 0.9.0
8235*************************
8240- the EXITSOL callback of the plugins is now called before the LP and the global cut pool are freed
8243 - new primal heuristics `rens`, `mutation` and `veclendiving`
8244 - primal heuristics that run before the node is solved now know already whether the LP will be solved at the current
8248 - new heuristic `intshifting` (ID character `i`)
8249 - in the root node of the very first run, heuristics with timing `AFTERNODELPNODE`, `AFTERLPPLUNGE`, `AFTERPSEUDONODE`, and
8250 `AFTERPSEUDOPLUNGE` are now called before the enforcement of the constraint handlers, in particular before the branching
8251 rules; in this way, the branching rule can already benefit from a tighter primal bound
8252 - if a heuristic found a better solution after the LP loop (and in particular the `AFTERNODE` heuristics in the root node
8253 of the very first run, see above), domain propagation and LP solving is triggered again; this allows for additional
8254 reduced cost tightening and other dual propagations
8255 - slightly modified `crossover` and `rins` heuristics
8256 - improved performance of intdiving heuristic
8257 - improved heuristic `octane` and `shifting`
8258 - slightly modified rens and localbranching heuristics
8259 - modified guided diving heuristic such that it equals the original version of the heuristic (i.e., round in direction of the
8260 current incumbent solution instead of the average of all primal feasible solutions)
8261 - ID character for intdiving heuristic is now `I`
8263- Separation and Cuts:
8264 - c-MIR cuts try now to scale the cut to integral values; however, cuts are still generated if this fails
8265 - hard-coded relative objective gain to consider a separation loop to be stalling is now changed from 1e-3 to 1e-4,
8266 which means that separation is not aborted as early as before
8267 - modified c-MIR cut separator to more closely resemble the original version of Marchand and Wolsey
8270 - possibility of SAT-like restarts after a number of conflict constraints have been found
8271 - improved presolving of and, or and xor constraints
8272 - implemented additional dual presolving in linear constraint handler
8273 - slightly modified presolving of varbound constraint handler
8278### New and changed callbacks
8280- new parameter `solinfeasible` for constraint handler callback methods `ENFOLP` and `ENFOPS`
8281- replaced callback parameter `inlploop` and `inplunging` by `heurtiming` in `SCIP_DECL_HEUREXEC`
8282- slightly changed the meaning of the result codes returned by external relaxators: if they modify the LP or tighten
8283 bounds of variables, they are not automatically be called again (it is assumed that they already made use of these
8284 changes). They are only called again, if they returned `SCIP_SUSPENDED` or if some other plugin modified the LP.
8286### Deleted and changed API methods
8288- new parameter `escapecommand` for SCIPdialoghdlrAddHistory()
8289- removed method SCIPgetVarData(); use SCIPvarGetData() from pub_var.h instead
8290- new calls SCIPgetLPBInvCol() and SCIPgetLPBInvACol() to access the basis inverse and simplex tableau columnwise
8291- new parameter `ndomredsfound` of SCIPpropagateProbing()
8292- new parameters `fixintegralrhs`, `maxfrac`, `mksetcoefs` and `fracnotinrange` in SCIPcalcMIR()
8293- modified SCIPfixVar() such that in problem creation stage it will change the bounds as requested even if the fixing
8294 value is outside of the current bounds
8295- replaced parameters `pseudonodes`, `duringplunging`, `duringlploop` and `afternode` by `timingmask` in
8296 SCIPincludeHeur() and constructor of ObjHeur() class use the following table to translate old settings into the new
8299| PSEUDONODES | DURINGPLUNGING | DURINGLPLOOP | AFTERNODE | timingmask |
8300|-------------|----------------|--------------|-----------|---------------------------------------------------------------|
8301| FALSE | FALSE | FALSE | FALSE | SCIP_HEURTIMING_BEFORENODE |
8302| TRUE | FALSE | FALSE | FALSE | SCIP_HEURTIMING_BEFORENODE |
8303| FALSE | TRUE | FALSE | FALSE | SCIP_HEURTIMING_BEFORENODE |
8304| TRUE | TRUE | FALSE | FALSE | SCIP_HEURTIMING_BEFORENODE |
8305| FALSE | FALSE | TRUE | FALSE | SCIP_HEURTIMING_BEFORENODE \| SCIP_HEURTIMING_DURINGLPLOOP |
8306| TRUE | FALSE | TRUE | FALSE | SCIP_HEURTIMING_BEFORENODE \| SCIP_HEURTIMING_DURINGLPLOOP |
8307| FALSE | TRUE | TRUE | FALSE | SCIP_HEURTIMING_BEFORENODE \| SCIP_HEURTIMING_DURINGLPLOOP |
8308| TRUE | TRUE | TRUE | FALSE | SCIP_HEURTIMING_BEFORENODE \| SCIP_HEURTIMING_DURINGLPLOOP |
8309| FALSE | FALSE | FALSE | TRUE | SCIP_HEURTIMING_AFTERLPPLUNGE |
8310| TRUE | FALSE | FALSE | TRUE | SCIP_HEURTIMING_AFTERPLUNGE |
8311| FALSE | TRUE | FALSE | TRUE | SCIP_HEURTIMING_AFTERLPNODE |
8312| TRUE | TRUE | FALSE | TRUE | SCIP_HEURTIMING_AFTERNODE |
8313| FALSE | FALSE | TRUE | TRUE | SCIP_HEURTIMING_AFTERLPPLUNGE \| SCIP_HEURTIMING_DURINGLPLOOP |
8314| TRUE | FALSE | TRUE | TRUE | SCIP_HEURTIMING_AFTERPLUNGE \| SCIP_HEURTIMING_DURINGLPLOOP |
8315| FALSE | TRUE | TRUE | TRUE | SCIP_HEURTIMING_AFTERLPNODE \| SCIP_HEURTIMING_DURINGLPLOOP |
8316| TRUE | TRUE | TRUE | TRUE | SCIP_HEURTIMING_AFTERNODE \| SCIP_HEURTIMING_DURINGLPLOOP |
8319 - renamed all occurences of `removeable` by the correct English word `removable`: SCIPconsIsRemovable(),
8320 SCIPsetConsRemovable(), SCIPvarIsRemovable(), SCIPcolIsRemovable(), SCIProwIsRemovable()
8321 - new parameter `sticktonode` in SCIPcreateCons(), SCIPcreateConsAnd(), SCIPcreateConsBounddisjunction(),
8322 SCIPcreateConsKnapsack(), SCIPcreateConsLinear(), SCIPcreateConsLogicor(), SCIPcreateConsOr(),
8323 SCIPcreateConsVarbound(), SCIPcreateConsXor(), SCIPcreateConsSetpart(), SCIPcreateConsSetpack(),
8324 SCIPcreateConsSetcover(): usually, you should set this to FALSE; if you want to add constraints as node markers with
8325 node data and, e.g., use the `activate` and `deactivate` callbacks to get informed about the activation and
8326 deactivation of the node, you should set this flag to TRUE in order to make sure, that the constraint will always be
8327 associated to the node and not moved to a more global node if this would be possible
8328 - slightly changed semantics of SCIPaddConsNode() and SCIPaddConsLocal(), such that a constraint which is added to the
8329 root node now enters the global problem (and is still existing after a restart)
8331### New API functions
8335- SCIPgetGlobalCutpool(), SCIPgetPoolCuts(), SCIPcutpoolGetCuts(), SCIPcutGetRow() and SCIPcutGetAge()
8336- SCIPconsGetNLocksPos() and SCIPconsGetNLocksNeg()
8338### Command line interface
8340- command shell now understands escape characters `\``,`'` and `\` which makes it possible to read in files with spaces in the
8343### Interfaces to external software
8345- updated XPress interface to XPress-MP 17 (contributed by Michael Perregaard)
8347### Changed parameters
8349- changed default value of `heuristics/octane/usediffray` to FALSE
8350- removed parameter `heuristics/octane/usediffbwray`
8351- renamed parameter `heuristics/octane/useavgray` to `heuristics/octane/useavgnbray`
8352- changed default value of `heuristics/rens/binarybounds` to TRUE
8353- changed default value of `heuristics/octane/freq` to -1 in order to deactivate Octane
8354- parameter `heuristics/feaspump/maxsols` is now strict, i.e., if n solutions were already found, the feasibility pump
8355 starts to work only if `maxsols <= n`, instead of `maxsols < n`
8359- `conflict/restartnum` and `conflict/restartfac`
8360- `heuristics/octane/useavgray`
8361- `heuristics/octane/useavgwgtray`
8362- `limits/absgap` to define an absolute gap limit
8363- `separating/cmir/aggrtol`
8364- `separating/cmir/densityscore`
8365- `separating/cmir/fixintegralrhs`
8366- `separating/maxruns`
8367- `presolving/restartminred` which forbids another restart if the last one was not successful enough
8368- `propagating/abortoncutoff`
8369- `reading/zplreader/changedir` to control behavior of path switching of ZIMPL file reader
8370- `reading/zplreader/parameters` to pass additional parameters to ZIMPL
8377- added ncurses to the readline entries in the `make/make.*` files
8378- added quotes to sed expressions in Makefile (needed under Windows)
8379- modified makefiles for Windows/Intel
8380- added automatic query script in the Makefile for soft-link names
8385- fixed bug with string pointer copy instead of string content duplication in constructors of C++ wrapper classes
8386- fixed bug in CPLEX interface with basis access methods that dualopt has to be called for more error status codes
8387- fixed bug with inserting two variable bounds of the same type on the same variable with the same bounding variable but
8388 with different sign of coefficient (e.g., `x <= 10*z + 5` and `x <= -5*z + 10`); in previous version, one of the two was
8389 removed, although both have a useful meaning; now, we keep both and detect a stronger global bound in the implication graph presolving
8390- objective function is now also checked for integrality after problem transformation (fixed a bug that a solution which
8391 was generated between transformation and presolving for an integral objective function did not reduce the cutoff bound by one)
8392- fixed a bug with cmir cut efficacy calculation (however, on my first tests, the performance reduced slightly!)
8393- fixed bug that SCIPvarGetAvgSol() always returned the upper bound (affected guided diving heuristic)
8394- fixed bug in RENS, RINS, Local Branching, Crossover and Mutation heuristics with wrong variable-subvariable assignments
8395- fixed bug in infeasible/bound-exceeding LP conflict analysis if the bounds were relaxed in diving (happens in intshifting heuristic)
8398 - fixed bug with adding constraints with `INITIAL=true` and separating them afterwards, which lead to a second addition of
8399 the constraint's relaxation in the child node
8400 - separation LPs are now immediately resolved after a bound change was generated by a cut separator; before, the
8401 separation round was prematurely aborted, which means that a separation round limit was sometimes reached very quickly
8402 and some of the separators were not even called a single time
8404- Cmir Cut Separator:
8405 - too large deltas are now also rejected in c-MIR cut separation
8406 - fixed bug in cmir cut separator, that 8*delta was not tried
8407 - fixed bug in cmir cut separator with wrong sign of slack in row score function
8408 - fixed bug in cmir cut separator with weights fixed to zero, thus making the current aggregation invalid
8409 - fixed bug in cmir cut separator with wrong calculation of cut efficacies
8411@page RN0_8 Release notes for SCIP 0.8
8413@section RN082 SCIP 0.8.2
8414*************************
8419- additional flag `delay` for pricers
8420- new propagator `rootredcost` which applies reduced cost fixing at the root node whenever a best new primal solution was found
8421- new separator `redcost` which replaces the internal reduced cost strengthening
8424 - extensions to the LP are kept even if the LP is not solved at the current node; however, if the LP turned out to be
8425 numerically instable, the extensions of the current node are still discarded
8426 - added removal of bound-redundant rows from the LP during root node LP solving loop
8427 - new display column `lpobj`
8430 - slightly changed priorities of constraint handlers
8431 - now, conflict constraints are also created if they were generated in strong branching or diving with insertion depth
8432 equal to the current depth
8433 - new constraint handler `bounddisjunction`
8436 - renamed `sol` file reader to `fix` file reader (reads partial solution files and fixes variables to the given values)
8437 - added `sol` file reader which reads complete solution files and adds the solutions to the solution pool
8438 - LP and MPS file readers are now able to parse lazy constraints and user cuts sections
8441 - knapsack presolver now generates cliques in the clique table (this essentially solves `neos1.mps`)
8442 - new presolver `inttobinary`
8445 - new primal heuristic `shifting`
8446 - diving heuristics abort earlier (did not come back in reasonable time on `fast0507`)
8451- new solution status code `SCIP_STATUS_STALLNODELIMIT`
8453### New and changed callbacks
8455- slightly modified semantics of the `CONSINITLP` callback in the constraint handlers
8457### Deleted and changed API methods
8459- methods SCIPisLbBetter() and SCIPisUbBetter() have an additional parameter and slightly different meaning (they now
8460 compare the bound improvement *relatively* to the width of the domain and the bound itself)
8461- SCIPgetNSols() now returns an int instead of `SCIP_Longint`
8462- method SCIPreadProb() does not call SCIPfreeTransform() anymore; file readers that want to extend the existing problem
8463 must now call SCIPfreeTransform() themselves before modifying the original problem
8464- method SCIPgetBinvarRepresentative() can now also be called in problem creation stage
8465- additional parameter `maxpricerounds` in method SCIPsolveProbingLPWithPricing()
8466- changed name of method SCIPpresolGetNVarTypes() to SCIPpresolGetNChgVarTypes()
8467- method SCIPsplitFilenames() now treats both versions of slashes, `/` and `\`, as directory delimiters (under MinGW and
8468 CygWin, both are valid; so, we cannot treat file names anymore where the other slash is used as a regular character)
8471 - marking a constraint to be `initial` now means in addition, that if the constraint is added to a local node it will
8472 enter the LP at the time the node is first processed, even if parameters forbid separation at this node
8473 - changed name of method SCIPconshdlrGetNVarTypes() to SCIPconshdlrGetNChgVarTypes()
8476 - method SCIPgetNConflictClausesFound() renamed to SCIPgetNConflictConssFound()
8477 - method SCIPgetNConflictClausesFoundNode() renamed to SCIPgetNConflictConssFoundNode()
8478 - method SCIPgetNConflictClausesApplied() renamed to SCIPgetNConflictConssApplied()
8480### New API functions
8482- SCIPsolveProbingLPWithPricing()
8483- SCIPchgVarLbRoot() and SCIPchgVarUbRoot()
8484- SCIPinRepropagation()
8485- SCIPaddDialogInputLine() and SCIPaddDialogHistoryLine()
8486- SCIPtransformProb() to create the transformed problem; enables the user, e.g., to add primal solutions before the presolving begins
8487- SCIPcreateSolCopy()
8491 - SCIPgetRowKnapsack(), SCIPgetRowLinear(), SCIPgetRowLogicor(), SCIPgetRowSetppc(), and
8492 SCIPgetRowVarbound() for obtaining the linear relaxation of a corresponding constraint
8493 - SCIPgetLhsVarbound(), SCIPgetRhsVarbound(), SCIPgetVarVarbound(), SCIPgetVbdvarVarbound(), and
8494 SCIPgetVbdcoefVarbound()
8495 - SCIPgetLPRootObjval(), SCIPgetLPRootColumnObjval() and SCIPgetLPRootLooseObjval()
8496 - SCIPcolGetMinPrimsol() and SCIPcolGetMaxPrimsol()
8497 - SCIPgetFocusDepth()
8500 - SCIPgetAvgPseudocostScore()
8501 - SCIPgetAvgPseudocostScoreCurrentRun()
8502 - SCIPgetAvgConflictScore()
8503 - SCIPgetAvgConflictScoreCurrentRun()
8504 - SCIPgetAvgInferenceScore()
8505 - SCIPgetAvgInferenceScoreCurrentRun()
8506 - SCIPgetAvgCutoffScore()
8507 - SCIPgetAvgCutoffScoreCurrentRun()
8510 - SCIPgetColRedcost()
8511 - SCIPvarGetRootRedcost()
8514 - SCIPgetNVarsAnd() and SCIPgetVarsAnd()
8515 - SCIPgetWeightsKnapsack(), SCIPgetNVarsKnapsack(), SCIPgetVarsKnapsack() and SCIPgetWeightsKnapsack()
8516 - SCIPgetNVarsLinear(), SCIPgetVarsLinear() and SCIPgetValsLinear()
8517 - SCIPgetNVarsOr() and SCIPgetVarsOr()
8518 - SCIPgetNVarsXor() and SCIPgetVarsXor()
8520### Command line interface
8522- command line syntax changed to support batch modus without piping stdin with `<` or `|` operators
8523- advanced command line syntax:
8524 - `-l <logfile> `: copy output into log file
8525 - `-q `: suppress screen messages
8526 - `-s <settings> `: load parameter settings (.set) file
8527 - `-f <problem> `: load and solve problem file
8528 - `-b <batchfile>`: load and execute dialog command batch file (can be used multiple times)
8529 - `-c <command> `: execute single line of dialog commands (can be used multiple times)
8531### Interfaces to external software
8533### Changed parameters
8535- removed parameter `propagating/redcostfreq`, because reduced cost strengthening is now an external separator plugin
8536- removed parameter `conflict/maxunfixed`
8537- parameter `conflict/maxclauses` renamed to `conflict/maxconss`
8538- parameter `conflict/interclauses` renamed to `conflict/interconss`
8539- parameter `conflict/reconvclauses` replaced by `conflict/reconvlevels`
8540- parameter `conflict/uselp` replaced by `conflict/useinflp` and `conflict/useboundlp`
8541- changed default value of `constraints/obsoleteage` to -1
8542- changed default value of `branching/relpscost/conflictweight` to 0.01
8543- changed default value of `branching/relpscost/inferenceweight` to 0.0001
8544- changed default value of `branching/relpscost/cutoffweight` to 0.0001
8545- in bfs node selector, parameter `minplungedepth` is now stronger than `maxplungedepth` if they conflict
8549- `constraints/linear/separateall`
8550- `conflict/lpiterations`
8551- `conflict/keepreprop`
8552- `branching/relpscost/conflictweight`, `branching/relpscost/inferenceweight`,
8553 `branching/relpscost/cutoffweight` and `branching/relpscost/pscostweight`
8554- `conflict/settlelocal`
8555- `conflict/depthscorefac`
8556- `limits/stallnodes`
8563- removed ncurses and pthread libraries from the Makefile; pthread is now only linked if CPLEX is used
8568- fixed numerical bug in SCIPrealToRational() [thanks to Anders Schack-Nielsen]
8569- fixed bug in crossover heuristic with negative timelimit
8570- removed bug in conflict analysis with wrong redundancy check
8571- fixed bug that unexpected end of stdin (Ctrl-D or piped-in file without `quit` command) gives a segmentation fault
8572- fixed bug with inconsistent data structures after a global bound was changed at a local subproblem and the local
8573 bounds are not contained anymore in the new global bounds
8574- fixed dependency generation in example Makefiles
8577 - fixed bug in knapsack presolving with redundancy check after applyFixings() [thanks to Anders Schack-Nielsen]
8578 - fixed bug in knapsack separator with empty initial covers
8579 - fixed bug in knapsack constraint disaggregation that may lead to acceptance of infeasible solutions
8580 - fixed bug in knapsack constraint handler where a modifiable constraint may be declared redundant
8583 - fixed bug with missing LP size updates after pricing or cut separation in probing [thanks to Marc Nuenkesser]
8584 - fixed bug in CPLEX interface with getting basis information after the LP was modified and restored
8585 - fixed bug with updating LP size in probing
8586 - fixed bug that SCIPgetLPSolstat() returns a valid status code even if the LP was not yet constructed for the current node
8589 - fixed bug with invalid lazy updates after a restart where the LP is not solved again (e.g., due to all variables being fixed)
8590 - fixed bugs resulting from inactive general integer variables being member of the variable bounds array of a variable
8591 - fixed bug in updatePseudocost() with wrong lpgain distribution on multiple branching variables [thanks to Anders Schack-Nielsen]
8592 - fixed bug in objconshdlr.h where member variable scip_maxprerounds_ was declared as an `SCIP_Bool` instead of an int
8593 - branching on nearly-integral variables is now avoided in relpscost branching, which lead to a numerical assertion
8596 - fixed bug with adding implications that fix the implication variable to the opposite value (due to the bug, it was
8597 returned that the whole problem is infeasible)
8598 - removed wrong assert in varRemoveImplicsVbs()
8601 - fixed bug in SCIPcliqueSearchVar() [thanks to Anders Schack-Nielsen]
8602 - fixed bug in SCIPcliqueAddVar() [thanks to Anders Schack-Nielsen]
8605 - fixed bug in MPS file reader with `OBJSENSE`
8606 - fixed bug in LP reader with potentially uninitialized pointers [thanks to Martin Mueller]
8609 - it is now possible to branch on constraints without the risk of going into an infinite loop, because constraints marked as `initial`
8610 will be put to the LP relaxation (of the child nodes) even if separation is prohibited by the parameter settings
8611 - fixed bug that locally valid varbound constraints produce VLB/VUB entries [thanks to Anders Schack-Nielsen]
8613@section RN081 SCIP 0.8.1
8614*************************
8619- improved performance of the priority queue in conflict analysis
8620- slightly modified restartdfs node selector
8623 - new presolver `implics` to find bound changes and aggregations out of the implication graph
8624 - modified probing order in probing presolver
8627 - changed handling of added constraints in separation calls
8628 - modified bookkeeping of locally added and disabled constraints such that the order of enabling and disabling constraints stays the same
8629 - logic or constraint handler now adds implications on clauses with 2 literals to the implication graph
8630 - and/or constraint handlers now add implications to the implication graph
8631 - xor constraint handler now uses stronger LP relaxation without auxiliary variable for xor constraint with 2 operands
8634 - added preliminary version of `intdiving` heuristic (disabled in default settings)
8635 - added crossover heuristic
8638 - LP file reader now accepts the keyword `Integer` for defining the start of the integer variables section
8639 - new file reader for (partial) solutions
8641Examples and applications
8642-------------------------
8644- added two small pricer examples (for C and C++)
8645- updated example code (s.t. it compiles again)
8650### New and changed callbacks
8652- callback method `CONSSEPA` of constraint handler was split into two methods `CONSSEPALP` and `CONSSEPASOL`
8653- callback method `SEPAEXEC` of separator was split into two methods `SEPAEXECLP` and `SEPAEXECSOL`
8655### Deleted and changed API methods
8657- replaced method SCIPsepaWasDelayed() by SCIPsepaWasLPDelayed() and SCIPsepaWasSolDelayed()
8658- additional parameter `sol` for methods SCIPaddCut(), SCIPgetCutEfficacy() and SCIPisCutEfficacious()
8659- additional parameter `sol` for method SCIPseparateKnapsackCover()
8660- primal solutions may now contain values marked to be unknown (value is `SCIP_UNKNOWN`); unknown values don't contribute
8661 to the objective value of the solution; an unknown solution value should be treated as an arbitrary value in the
8662 variable's bounds, e.g., in the calculation of the feasibility of a constraint, a value inside the variable's bounds
8663 should be selected that makes the constraint as feasible as possible
8664- new parameter `printzeros` for methods SCIPprintSol(), SCIPprintTransSol(), SCIPprintBestSol() and SCIPprintBestTransSol()
8667 - replaced method SCIPconshdlrWasSeparationDelayed() by two methods SCIPconshdlrWasLPSeparationDelayed() and
8668 SCIPconshdlrWasSolSeparationDelayed()
8669 - renamed method SCIPgetNGlobalConss() to SCIPgetNConss()
8671### New API functions
8674- SCIPgetVarConflictScore() and SCIPgetVarConflictScoreCurrentRun()
8676- SCIPcreateUnknownSol()
8677- SCIPgetNConflictClausesFoundNode()
8678- SCIPvarSetDelorigData(), SCIPvarSetTransData() and SCIPvarSetDeltransData()
8679- SCIPvarHasBinaryImplic()
8680- SCIPgetFixedVars() and SCIPgetNFixedVars()
8681- SCIPgetConss(), SCIPgetNOrigConss() and SCIPgetOrigConss()
8682- SCIPsepaGetNConssFound() and SCIPsepaGetNDomredsFound()
8683- SCIPconstructLP() to force constructing the LP of the current node
8684- SCIPisLPConstructed()
8686### Command line interface
8688- added `write statistics` command to default user dialogs
8690### Changed parameters
8692- modified meaning of parameter `presolving/probing/maxtotaluseless`
8693- heuristics with `freq = 0` and `freqofs > 0` are now called in depth level freqofs instead of being called in the root
8695- added some parameters in local branching and RINS heuristic
8696- new parameter values `p`rimal simplex and `d`ual simplex in `lp/initalgorithm` and `lp/resolvealgorithm`
8700- `branching/inference/conflictweight`
8707- included version number in binary file name
8708- tried to make the code Windows compatible
8713- also removed history_length, if `NO_REMOVE_HISTORY` is defined to support older versions of the readline library
8714- hopefully fixed bug with wrong path slash `/` under Windows
8715- fixed bug with aggregating fixed variables
8718 - fixed bug in transitive implication addition
8719 - fixed wrong assert with implications that imply a fixed variable
8720 - removed bug in implication addition
8723 - fixed bug in ZIMPL model reader with wrong chdir, if .zpl file is in current directory
8724 - fixed bug in LP file reader with signed values without space between sign and value (e.g. `+2x` instead of `+ 2x`)
8725 - fixed various bugs in LP file reader
8726 - fixed bug in LP file reader with explicit zero coefficients
8729 - fixed numerics in probing and linear constraint handler (rentacar was detected to be infeasible in presolving)
8730 - fixed numerics in check method of linear constraint handler
8731 - fixed bug with numerical error in LP resolve after probing or diving
8734 - fixed bug with calling heuristics in depths smaller than their frequency offset
8735 - fixed bugs in local branching and RINS heuristic
8740- if one uses column generation and restarts, a solution that contains variables that are only present in the
8741 transformed problem (i.e., variables that were generated by a pricer) is not pulled back into the original space
8742 correctly, since the priced variables have no original counterpart
8744@section RN080 SCIP 0.8.0
8745*************************
8750- adding variable bounds automatically adds the corresponding implication
8751- changed restart dfs nodeselector to sort leaves by node number instead of node depth to aviod jumping around in the
8752 search tree after a restart was applied and the current dive ended due to infeasibility
8753- new Message Handler plugin
8754- added file reader for LP format
8755- introduced subversion string
8756- replaced all abort() calls by SCIPABORT(); this is defined in def.h to be `assert(FALSE)`
8757- added possibility to disable certain features by using `make USRFLAGS=-DNO_REMOVE_HISTORY`, `make
8758 USRFLAGS=-DNO_SIGACTION`, `make USRFLAGS=-DNO_RAND_R`, or `make USRFLAGS=-DNO_STRTOK_R`
8759- improved preprocessing abort criteria
8763 - conflict clauses are now collected in a conflict store, redundant clauses are eliminated and only the best `conflict/maxclauses`
8764 clauses are added permanently to the problem; the remaining clauses are only added temporarily, if they can be used for repropagation
8765 - modified the influence of the depth level in conflict analysis
8766 - slightly changed LP resolving loop in conflict analysis
8767 - if CPLEX returns that the LP exceeds the bound and if no additional LP solves are allowed in conflict analysis, we
8768 have to perform one additional simplex iteration to get the dual solution that actually violates the objective limit
8771 - reactivated multiaggregation in cons_linear.c on binary variables again (possible due to bug fix below)
8772 - improved preprocessing of variable bounds constraints
8773 - linear constraint handler now catches events of variables after the problem was completely transformed in order to
8774 avoid the whole bunch of `LOCKSCHANGED` events that are generated at problem transformation stage
8775 - added redundancy detection for pairs of constraints in setppc constraint handler
8777- Presolving and Cliques:
8778 - changed linear constraint presolving s.t. redundant sides are not removed if constraint is an equality
8779 - new event type `SCIP_EVENTTYPE_PRESOLVEROUND`
8780 - modified probing presolver to not add implications that are already included in the implication graph and clique table
8781 - incorporated clique and implication information in knapsack constraint presolving
8782 - removed transitive clique generation, because this produces way too many cliques
8785 - diving heuristics now apply propagation at each step
8786 - removed `objfeaspump` heuristic, because the functionality can be achieved by using the `feaspump` heuristic
8787 - diving heuristics are now applying propagation after each bound change
8788 - new primal heuristic `octane`
8789 - slightly changed feaspump heuristic, s.t. after finding a new best solution the target integral solution is modified randomly
8791- Separation and Cuts:
8792 - improved debugging for infeasible cuts and propagations, given a primal feasible solution
8793 - improved knapsack cover separation
8794 - improved performance of c-MIR separator
8795 - cut pool is now also separated in root node (to find cuts again that were removed from the LP due to aging)
8800- new event type `SCIP_EVENTTYPE_VARDELETED`
8801- new event `SCIP_EVENTTYPE_IMPLADDED`
8802- new event types `SCIP_EVENTTYPE_GLBCHANGED` and `SCIP_EVENTTYPE_GUBCHANGED`
8804### New and changed callbacks
8806- new callback parameter `validnode` for the `CONFLICTEXEC` method of conflict handlers, which should be passed to
8809### Deleted and changed API methods
8811- additional parameter `validnode` for SCIPaddConsLocal() and SCIPaddConsNode()
8812- SCIPhashtableRemove() can now also be called, if the element does not exist in the table
8813- SCIPhashmapRemove() can now also be called, if the element does not exist in the map
8814- additional parameter `branchdir` for SCIPbranchVar()
8815- replaced method SCIPmessage() by SCIPverbMessage() with additional parameter `file`
8816- put block memory shell and tclique algorithm into separate subdirectories
8817- new parameter `duringlploop` of SCIPincludeHeur(): heuristics can now run during the price-and-cut loop at a node
8819### New API functions
8821- SCIPgetNConflictClausesApplied()
8822- SCIPgetNConflictClausesApplied()
8823- SCIPhashtableExists()
8824- SCIPhashmapExists()
8825- SCIPnodeGetNumber()
8826- SCIPsolveProbingLP() to solve the LP in a probing node (enables mixing of propagation and LP solving for diving heuristics)
8827- SCIProwGetDualfarkas()
8828- SCIPgetCurrentNode()
8829- SCIPinterruptSolve()
8830- SCIPpropagateProbingImplications()
8831- SCIPgetLPI() which makes all methods in scip/lpi.h available to the user
8832- SCIPgetRandomInt() and SCIPgetRandomReal()
8834- SCIPheurGetNBestSolsFound()
8838 - SCIPgetVarStrongbranchLPAge()
8839 - SCIPvarIsTransformedOrigvar()
8840 - SCIPvarIsDeleted()
8843 - SCIPerrorMessage()
8844 - SCIPwarningMessage()
8845 - SCIPdialogMessage()
8847 - SCIPsetMessagehdlr()
8848 - SCIPsetDefaultMessagehdlr()
8849 - SCIPgetMessagehdlr()
8850 - new file i/o methods SCIPfopen(), SCIPfclose(), SCIPfprintf(), ... that operate on the data type `SCIPFILE`; these
8851 methods automatically use zlib methods if the zlib is enabled
8854 - SCIPvarGetNCliques()
8855 - SCIPvarGetCliques()
8856 - SCIPvarsHaveCommonClique()
8857 - SCIPvarHasImplic()
8858 - SCIPcliqueGetNVars()
8859 - SCIPcliqueGetVars()
8860 - SCIPcliqueGetValues()
8863 - SCIPcalcCliquePartition()
8865- Constraint handler:
8866 - SCIPgetDualfarkasLinear() of linear constraint handler
8867 - SCIPgetDualfarkasLogicor() of logicor constraint handler
8868 - SCIPgetDualfarkasSetppc() of setppc constraint handler
8869 - SCIPgetDualsolKnapsack() of knapsack constraint handler
8870 - SCIPgetDualfarkasKnapsack() of knapsack constraint handler
8871 - SCIPgetDualsolVarbound() of varbound constraint handler
8872 - SCIPgetDualfarkasVarbound() of varbound constraint handler
8873 - SCIPconsGetValidDepth()
8874 - SCIPsetConsInitial()
8875 - SCIPsetConsSeparated()
8876 - SCIPsetConsEnforced()
8877 - SCIPsetConsChecked()
8878 - SCIPsetConsPropagated()
8879 - SCIPsetConsLocal()
8880 - SCIPsetConsDynamic()
8881 - SCIPsetConsRemoveable()
8883### Command line interface
8885- added command `write solution` to default dialog
8886- added commands `write problem` and `write transproblem` to default dialog
8888### Changed parameters
8890- additional setting `SCIP_VERBLEVEL_DIALOG` in `display/verblevel` parameter
8891- additional LP pricing setting `partial`
8892- replaced parameter `presolving/restartbdchgs` with parameters `presolving/maxrestarts` and `presolving/restartfac`
8893- replaced parameter `constraints/linear/maxpresolaggrrounds` with `constraints/linear/maxpresolpairrounds`
8894- parameters `constraints/agelimit` and `constraints/obsoleteage` now iterprete the value 0 as a dynamic setting
8895- number of fractional variables included in parameter `separating/maxstallrounds`
8897- Changed default values:
8898 - changed default values of `heuristics/∗/maxdiveavgquot` and `heuristics/∗/maxdiveavgquotnosol` to 0
8899 - changed default values of `constraints/agelimit` and `constraints/obsoleteage` to 0
8900 - changed default values of `heuristics/objpscostdiving/maxsols` and `heuristics/rootsoldiving/maxsols` to -1
8901 - changed default value of `separating/strongcg/maxroundsroot` to 20
8902 - changed default value of `separating/cmir/maxroundsroot` to 10
8903 - changed default value of `constraints/linear/maxaggrnormscale` to 0.0, which means to not apply aggregation
8904 - changed default value of `separating/maxstallrounds` to 5
8905 - changed default value of `presolving/probing/maxfixings` to 50
8906 - changed default parameter values to MIP settings:
8907 + `conflict/useprop` = FALSE
8908 + `conflict/usepseudo` = FALSE
8909 + `display/verblevel` = 4
8910 + `separating/poolfreq` = 0
8911 + `constraints/linear/sepafreq` = 0
8912 + `constraints/and/sepafreq` = 0
8913 + `constraints/conjunction/sepafreq` = 0
8914 + `constraints/knapsack/sepafreq` = 0
8915 + `constraints/knapsack/sepacardfreq` = 0
8916 + `constraints/logicor/sepafreq` = 0
8917 + `constraints/or/sepafreq` = 0
8918 + `constraints/setppc/sepafreq` = 0
8919 + `constraints/varbound/sepafreq` = 0
8920 + `constraints/xor/sepafreq` = 0
8921 + `separating/clique/freq` = 0
8922 + `separating/cmir/freq` = 0
8923 + `separating/gomory/freq` = 0
8924 + `separating/impliedbounds/freq` = 0
8925 + `separating/strongcg/freq` = 0
8929- `branching/fullstrong/reevalage`
8930- `conflict/maxclauses`
8931- `conflict/allowlocal`
8932- `constraints/knapsack/disaggregation`
8933- `presolving/probing/maxtotaluseless`
8934- `separating/cmir/maxfails`, `separating/cmir/maxfailsroot` and `separating/cmir/trynegscaling`
8938- MAJOR CHANGE: preceeded all data types with `SCIP_`: you may use shell script reptypes_scip.sh to rename the SCIP
8939 data types in your own source code (But use with care! Create a backup copy of your source first!)
8946- modified the Makefile to accept an additional parameter `VERBOSE={true,false}`
8947- added flags `READLINE=true/false`, `ZLIB=true/false`, `ZIMPL=true/false` to Makefile
8952- fixed minor bugs in debug code of primal.c and sol.c
8953- variables that are being multiaggregated are now automatically removed from all other variables' variable bound and
8954 implication arrays; this fixes bugs with methods, that rely on the fact, that the entries in the variable bound and
8955 implication arrays are active variables only
8956- aggregations are now always performed in a way, such that the variable of more general type is aggregated (with type
8957 generality being cont > implint > int > bin); in this way, a binary variable's representant is always binary (which
8958 was not the case before and resulted in a bug in SCIPgetBinvarRepresentative())
8959- removed bug in presol_probing.c: the vars of the sorted variables array have to be captured
8960- fixed bug in the output of solutions with priced variables
8961- fixed bug in propagation with parameters prop_maxrounds and prop_maxroundsroot
8962- conflict analysis can now handle errors in LP solving calls
8963- removed bug in SCIPvarAddVlb() and SCIPvarAddVub() with fractional vlb/vubcoefs
8964- fixed bug that primal or dual rays might not be available because the wrong solver was used
8965- included message.o in LPI library, s.t. one can link this library indepentent of SCIP
8966- fixed bug that if diving heuristic that changes the objective values finds a solution, the cutoff is reinstalled in
8967 the LP solver (although the objective value has no meaning due to the objective function modification)
8970 - LP primal feasibility for bounds is now defined as absolute measure (was relative to the bound before); this fixes a bug (see alu8_9.mps),
8971 that an LP with an integral variable fixed to a large value yields an accepted solution with that variable slightly different than the fixed
8972 value; the integrality feasibility condition is measured with absolute differences, which leads to the fixed integer variable being fractional;
8973 this leads to an error if branching is performed on this variable
8974 - fixed bug with redundant self implications that wrongly lead to the detection of infeasibility
8975 - fixed bug with potential infinite loop if a separator is delayed and the LP is infeasible
8978 - removed wrong asserts from lpi_cpx.c
8979 - removed wrong assertion in varAddImplic()
8982 - locally fixed variables are no longer used as branching candidates even if their LP solution value is fractional (due
8983 to numerical reasons, see above)
8984 - fixed numerical bug in pseudo objective propagator with only slightly tightened bounds
8985 - removed bug that an LP might be declared to be solved even if it was marked erroneous due to numerical problems
8987- Constraint Handlers:
8988 - fixed bug in linear constraint handler with variables fixed to infinity
8989 - fixed bug with constraint handlers that can only enforce their constraints by adding cuts, but the maximal number of
8990 cuts to separate is set to 0; now, cuts that are generated in the constraint enforcement are used in any case
8991 - fixed bug in knapsack constraint presolving with tightening coefficients and capacity
8992 - fixed bug with modifiable constraints in linear constraint handler preprocessing
8993 - fixed bug in linear constraint handler that global activities are not updated after global bound changes
8995- Separation and Cuts:
8996 - global bound changes now lead to the removal of redundant implications (such that the asserts in sepa_implbounds.c are now correct)
8997 - due to usage of variable bounds, SCIPcalcMIR() may return LOOSE variables in the cut -> modified sepa_cmir.c, sepa_gomory.c and
8998 sepa_strongcg.c to use SCIPcreateEmptyRow() and SCIPaddVarsToRow() instead of SCIPcreateRow() which only works for COLs
8999 - fixed bug in clique separator that reduced performance
9000 - increased performance of clique separator by allowing only a certain number of zero-weighted fill ins
9002@page RN0_7 Release notes for SCIP 0.7
9004@section RN079 SCIP 0.7.9
9005*************************
9010- aging and cleanup now only remove non-basic columns and basic rows, s.t. resolving can be applied with 0 simplex iterations
9011- it is now possible to create subnodes in probing and use backtracking to undo probing changes
9012- bounds of variables are included in the feasibility checks for solutions
9013- support for barrier algorithm
9014- changed implementation of automatic minplungedepth and maxplungedepth calculation in bfs node selector
9017 - new plugin: probing presolver
9018 - probing is now also possible in presolving stage
9019 - it is now possible to interrupt and continue presolving
9021- Separation and Cuts:
9022 - new plugin: clique separator for clique cuts with at least 3 elements
9023 - new plugin: implied bound cuts separator
9024 - included debugging module to check whether cutting planes cut off the optimal solution
9027 - changed implementation of reliability value calculation in reliability branching; slightly modified influence of
9028 maximal total number of strong branching LP iterations in reliability branching
9029 - changed implementation of maximal strong branching iterations calculation in reliability branching
9032 - if verblevel is at least `NORMAL`, an automatical check of the best solution is performed in the original problem, and
9033 an error message is displayed, if it violates an original constraint
9034 - due to the new constraint handler `cons_cumulative.{c,h}` SCIP can resource-constraint scheduling problem
9035 - during probing, propagation of bounds is now always performed in linear constraint handler, ignoring the parameter `tightenboundsfreq`
9036 - new implementation of the clique graph construction method in clique separator
9037 - new constraint handler `cons_cumulative.{c,h}`
9040 - new implementation of the feasibility pump heuristic by Timo Berthold (replaces old implementation); old
9041 implementation is now called `objfeaspump`; parameter names have been changed accordingly
9042 - diving heuristics now compare their number of LP iterations with the number of node LP iterations instead of the total
9043 number (including their own) LP iterations
9044 - modified the automatic objfactor setting of feaspump heuristic to let the objective function have stronger influence
9046Examples and applications
9047-------------------------
9049- added TSP example in `examples/TSP`
9054### New and changed callbacks
9056- new callback methods `INITSOL` and `EXITSOL` for variable pricers, primal heuristics, conflict handlers, relaxators,
9057 separators, propagators, event handlers, node selectors and display columns
9058- callback method `CONFLICTEXEC` of conflict handlers receive additional parameters `dynamic` and `removeable`
9059- constraint handler callback methods `CONSLOCK` and `CONSUNLOCK` are replaced by a single method `CONSLOCK` with the number
9060 of locks being positive or negative
9062### Deleted and changed API methods
9064- calling SCIPaddCut() with `forcecut=TRUE` will add the cut to the LP even if it is redundant
9065- SCIPreadProb() does not free the current problem, this is done in SCIPcreateProb() now, which is usually
9066 called by a problem reader; in this way, a reader can generate `extra information` for the current problem, s.t. the
9067 full problem information can be distributed to different files read by different readers
9068- SCIPgetVarStrongbranch() and SCIPgetVarStrongbranchLast() now have two additional parameters that can be used
9069 to check, whether the returned values are correct dual bounds
9070- SCIPgetBinvarRepresentative() now returns the fixed or multi-aggregated variable instead of returning `NULL` or
9071 aborting with an error message
9072- SCIPdispDecimal() is replaced by SCIPdispInt() and SCIPdispLongint()
9073- additional parameter `maxproprounds` in SCIPpropagateProbing()
9074- changed memory interface (see memory.h), `MEMHDR` is now called `BLKMEM`
9075- source code was moved into subdirectories: replace includes `scip.h` by `scip/scip.h` and
9076 `objscip.h` by `objscip/objscip.h`; This should allow a user to have include files of the same name as the ones
9077 of SCIP, e.g. `tree.h` or `var.h`.
9078- event handlers are now available as C++ wrapper class
9079- new flag `afterrelaxation` for primal heuristics
9082 - removed method SCIPsolGetObj(), use SCIPgetSolOrigObj() or SCIPgetSolTransObj() instead
9083 - additional parameter `checkbounds` for SCIPtrySol(), SCIPtrySolFree(), SCIPcheckSol()
9086 - SCIPvarLock(), SCIPvarLockDown(), SCIPvarLockUp(), SCIPvarLockBoth(), SCIPvarUnlock(), SCIPvarUnlockDown(),
9087 SCIPvarUnlockUp() and SCIPvarUnlockBoth() are replaced by SCIPaddVarLocks() which returns a `RETCODE`
9088 - SCIPvarGetLbGlobal(), SCIPvarGetUbGlobal(), SCIPvarGetLbLocal() and SCIPvarGetUbLocal() now return the
9089 corresponding values of the transformed problem or current subproblem even for original problem variables
9090 - SCIPvarGetProbvar(), SCIPvarGetProbvarBinary() now return the fixed or multi-aggregated variable instead of
9091 returning `NULL` or aborting with an error message; in SCIPvarGetProbvarBinary(), the fixing of a fixed variable does
9092 not influence the negation status anymore
9093 - SCIPvarGetProbvarBound() returns the multi-aggregated variable instead of aborting with an error message
9094 - SCIPvarGetProbvarSum() does not set *var to `NULL` for fixed variables anymore; it may also return a
9095 multi-aggregated variable instead of aborting with an error message
9096 - SCIPaddVarImplication() now also adds variable lower and upper bounds, if the implied variable is non-binary
9097 - additional parameter `aggregated` in SCIPmultiaggregateVars()
9100 - SCIPvarLockDownCons(), SCIPvarLockUpCons(), SCIPvarUnlockDownCons() and SCIPvarUnlockUpCons() are replaced by
9101 SCIPlockVarCons() and SCIPunlockVarCons() which return a `RETCODE`
9102 - SCIPlockConsVars() and SCIPunlockConsVars() replaced with method SCIPaddConsLocks()
9103 - SCIPconshdlrGetNConss() is replaced by SCIPconshdlrGetNActiveConss() (returning the number of active
9104 constraints); method SCIPconshdlrGetNConss() does now return the total number of existing constraints, active and inactive
9105 - SCIPconshdlrGetStartNConss() is now called SCIPconshdlrGetStartNActiveConss()
9106 - SCIPconshdlrGetMaxNConss() is now called SCIPconshdlrGetMaxNActiveConss()
9107 - SCIPdisableConsNode() is replaced by SCIPdelConsNode()
9108 - SCIPdisableConsLocal() is replaced by SCIPdelConsLocal()
9109 - added new parameter `dynamic` to SCIPcreateCons() and all plugin methods SCIPcreateCons...()
9111### New API functions
9114- SCIPcreateOrigSol()
9115- SCIPwriteImplicationConflictGraph()
9118- SCIPgetVarNStrongbranchs()
9119- SCIPcolGetNStrongbranchs()
9120- SCIPfindSimpleRational()
9121- SCIPselectSimpleValue()
9124 - SCIPvarGetLbOriginal()
9125 - SCIPvarGetUbOriginal()
9126 - SCIPvarGetImplIds()
9127 - SCIPvarGetOrigvarSum()
9132 - SCIPenableConsSeparation()
9133 - SCIPdisableConsSeparation()
9134 - SCIPconsIsSeparationEnabled()
9137 - SCIPgetAvgPseudocost()
9138 - SCIPgetAvgPseudocostCurrentRun()
9139 - SCIPgetAvgPseudocostCount()
9140 - SCIPgetAvgPseudocostCountCurrentRun()
9141 - SCIPgetAvgInferences()
9142 - SCIPgetAvgInferencesCurrentRun()
9143 - SCIPgetAvgCutoffs()
9144 - SCIPgetAvgCutoffsCurrentRun()
9147 - SCIPisLPSolBasic() to check, whether the current LP solution is basic (i.e. due to a simplex algorithm or barrier with crossover)
9148 - SCIPgetNPrimalLPs()
9149 - SCIPgetNPrimalLPIterations()
9151 - SCIPgetNDualLPIterations()
9152 - SCIPgetNBarrierLPs()
9153 - SCIPgetNBarrierLPIterations()
9154 - SCIPgetNPrimalResolveLPs()
9155 - SCIPgetNPrimalResolveLPIterations()
9156 - SCIPgetNDualResolveLPs()
9157 - SCIPgetNDualResolveLPIterations()
9160 - SCIPsepaIsDelayed()
9161 - SCIPsepaWasDelayed()
9162 - SCIPpropIsDelayed()
9163 - SCIPpropWasDelayed()
9164 - SCIPpresolIsDelayed()
9165 - SCIPpresolWasDelayed()
9166 - SCIPconshdlrIsSeparationDelayed()
9167 - SCIPconshdlrIsPropagationDelayed()
9168 - SCIPconshdlrIsPresolvingDelayed()
9169 - SCIPconshdlrWasSeparationDelayed()
9170 - SCIPconshdlrWasPropagationDelayed()
9171 - SCIPconshdlrWasPresolvingDelayed()
9173### Command line interface
9175- command line history in interactive shell now only stores useful commands
9177### Interfaces to external software
9179- removed storing of dual norms in LPI state of CPLEX interface (too memory consuming)
9181### Changed parameters
9183- default frequency offset of fracdiving heuristic changed to 3
9184- default frequency offset of (new) feaspump heuristic changed to 0
9185- default frequency offset of objfeaspump heuristic changed to 8
9186- changed default priority of primal heuristics
9187- renamed parameter `limits/sol` to `limits/solutions`
9188- changed default check priority of knapsack constraint handler to -600000
9189- changed default priority of Gomory cut separator to -1000 (will now be called after constraint handlers!)
9190- changed default priority of strong CG cut separator to -2000
9191- changed default priority of cmir cut separator to -3000
9192- changed default of parameter `lp/pricing` to `s`teepest edge pricing
9193- default parameter `branching/relpscost/minreliable` changed to 1.0
9194- default parameter `branching/relpscost/maxlookahead` changed to 8
9195- default parameter `branching/relpscost/sbiterofs` changed to 100000
9196- default parameter `heuristics/coefdiving/maxlpiterquot` changed to 0.05
9197- default parameter `heuristics/fracdiving/maxlpiterquot` changed to 0.05
9198- default parameter `heuristics/guideddiving/maxlpiterquot` changed to 0.05
9199- default parameter `heuristics/linesearchdiving/maxlpiterquot` changed to 0.05
9200- default parameter `heuristics/pscostdiving/maxlpiterquot` changed to 0.05
9201- default parameter `heuristics/feaspump/freq` changed to 20
9202- default parameter `heuristics/objfeaspump/freq` changed to 20
9203- default parameter `heuristics/objpscostdiving/freq` changed to 20
9204- default parameter `heuristics/rootsoldiving/freq` changed to 20
9205- default parameter `separating/clique/maxtreenodes` changed to -1
9209- new parameter delay for presolvers
9210- new parameter delaypresol for constraint handlers
9211- `branching/scorefunc`
9212- `constraints/.../delaypresol`
9213- `constraints/.../delayprop`
9214- `constraints/.../delaysepa`
9216- `conflict/removeable`
9217- `heuristics/coefdiving/maxlpiterofs`
9218- `heuristics/feaspump/maxlpiterofs`
9219- `heuristics/feaspump/maxsols`
9220- `heuristics/fracdiving/maxlpiterofs`
9221- `heuristics/guideddiving/maxlpiterofs`
9222- `heuristics/linesearchdiving/maxlpiterofs`
9223- `heuristics/objfeaspump/maxlpiterofs`
9224- `heuristics/objfeaspump/maxsols`
9225- `heuristics/objpscostdiving/maxlpiterofs`
9226- `heuristics/objpscostdiving/maxsols`
9227- `heuristics/pscostdiving/maxlpiterofs`
9228- `heuristics/rootsoldiving/maxlpiterofs`
9229- `heuristics/rootsoldiving/maxsols`
9230- `heuristics/fixandinfer/proprounds` and `heuristics/fixandinfer/minfixings`
9231- `lp/cleanupcolsroot` and `lp/cleanuprowsroot` to distinguish cleanup settings between root node and other nodes
9232- `lp/checkstability` to disable stability check of LP solver's result code
9233- `lp/initalgorithm` and `lp/resolvealgorithm` for switching between simplex and barrier algorithm
9234- `lp/pricing` to set the pricing strategy used in the LP solver
9235- `numerics/barrierconvtol` to set the convergence tolerance in the barrier algorithm
9236- `presolving/.../delay`
9237- `propagating/.../delay`
9238- `reading/cnfreader/dynamicconss`
9239- `reading/mpsreader/dynamicconss`
9240- `separating/.../delay`
9244- new possible result `SCIP_DELAYED` for `EXEC` method of separators, presolvers and propagators and `SEPA`, `PROP` and
9245 `PRESOL` methods of constraint handlers
9250- fixed bug in MPS file reader
9251- removed bug with applying reduced cost strengthening before pricing in all necessary variables
9252- negated variables must also be reset in SCIPvarInitSolve()
9253- fixed documentation of `CONSLOCK`-method (missing parameter `scip` in SCIPaddVarLocks())
9254- included missing `objrelax.h` in includes of objscip.h
9255- fixed bug that after a resolve and further preprocessing, existing primal solutions may get corrupted due to
9256 aggregations or fixings that are possible due to the primal bound (given by the best solution)
9257- fixed bug with primal bound becoming wrong, if in a prior run the optimal solution was found and the cutoff bound was
9258 thereby reduced due to further domain propagation w.r.t. the objective function
9259- fixed bug in SCIPisObjIntegral()
9260- fixed bug in SCIPprintError() with `file == NULL`
9261- heuristic's display character is now only shown the first time, the new solution was found
9262- fixed bug that SCIPreadProb() doesn't discard the transformed problem
9263- fixed bug with wrong euclidean norm calculation of row, if multiple coefficients for the same variable are added and
9264 the sorting of the row was delayed with SCIProwDelaySort()
9265- fixed bug with adding implications: wrong insertion position, if only the lower bound change was present but not the
9267- fixed bug in SCIPvarAddImplics() with wrong variable used in varAdjustBd()
9268- fixed bug in method reduced() of tclique_branch.c with sorting nodes in V
9271 - removed bug with objective norm calculation and column variables not in the LP (pricing)
9272 - LP error on forced LP resolve (due to 0 unfixed integers) now leads to an error (instead of accepting the pseudo
9273 solution as feasible)
9274 - fixed bug in CPLEX LP interface with dual norms
9277 - fixed bug that presolving time is not counted to solving time, if presolving is called explicitly with SCIPpresolve()
9278 - fixed bug where presolving fixings are counted even if the variable was already fixed
9279 - removed bug with dual presolver, that declared a problem to be unbounded or infeasible, if it could fix a variable to
9280 infinity even if its objective value is zero
9281 - fixed bug in knapsack constraint handler that fixed variables are sometimes not removed in presolving
9284 - fixed bug with unresolved numerical troubles in LP that don't render the LP useless at the current node
9285 - fixed numerical bugs in rounding heuristic and rootsoldiving heuristic
9288 - fixed bugs in separation store with single coefficient cuts that are converted into bound changes
9289 - at least one cut per separation round is added to the LP to avoid cycling, even if the cut is redundant
9290 - fixed bug in SCIProwCalcIntegralScalar() with rows consisting of only continuous variables (appeared in gomory cut
9291 separator on miplib/dcmulti.mps)
9292 - fixed bug in linear constraint handler's knapsack relaxation separator
9293 - fixed bugs in intobj separator
9294 - fixed bug in cmir separator with empty rows
9295 - fixed bug in implied bound cut separator: only implications between binary variables were generated before
9297- Constraint Handlers:
9298 - removed bug in knapsack constraint handler with merging multiple items if more than two items of the same variable
9299 appear in the constraint
9300 - removed bug in knapsack constraint handler with merging negated variables of equal weight at the end of the variables' array
9301 - fixed bug in linear constraint handler with eventdatas, if the original constraint has no variables
9302 - fixed bug that `CONSLOCK` method of constraint handlers that don't need constraints is not called
9303 - fixeg bug in setppc constraint handler with pairs of aggregated variables in the same constraint
9304 - fixed bug with globally deleting constraints, that have attached rows which are therefore not released in exitsol methods
9307 - removed conflict analysis of infeasible diving LP if pricing is activated
9308 - made conflict analysis available in presolving stage (for probing conflicts)
9310@section RN078 SCIP 0.7.8
9311*************************
9316- changed SCIProwCalcIntegralScalar() to a slightly different algorithm
9317- improved knapsack relaxation in linear constraint handler separator to scale the constraint in order to get integral
9318 coefficients instead of just rounding down all coefficients
9319- improved presolving of linear constraint handler: aggregation of two constraints with equal coefficient vector into
9321- improved presolving of knapsack constraint handler: aggregation of equal or negated variables in same constraint
9324 + priority of separators, propagators and presolvers decide whether the plugin is called before the corresponding
9325 constraint handler methods or after: plugins with nonnegative priorities are called before, plugins with negative
9326 priorities are called after the constraint handlers
9327 + new plugin class for relaxators (external relaxations, that can be used in parallel with LP relaxations)
9328 + if more than one result code applies to a plugin's execution, it should return the one that is higher in the call's
9334- even in optimized mode, the simple functions that are implemented as defines in the include files exist in the
9335 library, s.t. one can include the include files without `NDEBUG` and use the optimized library
9337### New and changed callbacks
9339- new branching rule plugin methods `INITSOL` and `EXITSOL`
9341### Deleted and changed API methods
9343- removed SCIPisFeasible(); use !SCIPisFeasNegative() instead
9344- SCIPisIntegral(), SCIPisFracIntegral(), SCIPfloor(), SCIPceil() and SCIPfrac() don't use the feasibility
9345 tolerance anymore (default: 1e-06); instead, they are using epsilon (default: 1e-09); instead, for handling
9346 integrality of a variable `in feasibility tolerances`, new methods SCIPisFeasIntegral(), SCIPisFeasFracIntegral(),
9347 SCIPfeasFloor(), SCIPfeasCeil() and SCIPfeasFrac() should be used
9348- in LPI, the semantics of SCIPlpiHasPrimalRay() and SCIPlpiHasDualRay() changed: methods return TRUE, if a ray exists
9349 and the solver can return it; new methods SCIPlpiExistsPrimalRay() and SCIPlpiExistsDualRay() check whether a ray
9350 exists without checking, if the solver knows and can return the ray
9352### New API functions
9355- SCIPgetLPColumnObjval() and SCIPgetLPLooseObjval()
9356- SCIPcalcIntegralScalar() with arbitrary array of Real values
9357- SCIPaddCoefKnapsack() in knapsack constraint handler
9358- SCIPisScalingIntegral() to check, whether the scaling of a value would lead to an integral value, measured
9359 against epsilon which is also scaled by the same scalar
9360- SCIPgetRealarrayMinIdx(), SCIPgetRealarrayMaxIdx(), SCIPgetIntarrayMinIdx(), SCIPgetIntarrayMaxIdx(),
9361 SCIPgetBoolarrayMinIdx(), SCIPgetBoolarrayMaxIdx(), SCIPgetPtrarrayMinIdx() and SCIPgetPtrarrayMaxIdx()
9362- SCIPbsortPtrInt() and SCIPbsortPtrIntInt()
9363- SCIPvarWasFixedAtIndex()
9364- SCIPaddConflictBd()
9365- SCIPprintMemoryDiagnostic()
9366- SCIPfindObj...() and SCIPgetObj...() in C++ wrapper interface to get the corresponding plugin object
9368### Changed parameters
9370- slightly changed the meaning of parameter `presolving/abortfac` a value of 0 now means to abort presolving only after
9371 no more change has been found
9376- assigning a value to a fixed variable in a solution with SCIPsetSolVal() does not return an error anymore, if the
9377 value is equal to the fixed value of the variable
9378- removed bug in SCIPisScalingIntegral()
9379- removed bugs with calling SCIPtightenVarLb(), SCIPtightenVarUb(), SCIPinferVarLbCons(), SCIPinferVarUbCons(),
9380 SCIPinferVarLbProp() and SCIPinferVarUbProp() in `PROBLEM` stage
9383 - solving loop is now immediately aborted, if a node on the active path is marked to be cut off
9384 - removed bug in resolving an interrupted problem, after the last solved node was cut off
9385 - removed bug with infinite solving loop if LP solving is turned off
9386 - removed bug with aborted solving in root node (e.g. due to time limit) that is tagged to be restarted
9389 - fixed bug in all-fullstrong branching with getting strong branching information for columns not in current LP
9390 - implemented missing case in solve.c with branching rules that add constraints
9393 - changed numerics for integrality check of coefficients (fixed bug with accumulated errors in rows s.t. the row's
9394 activity is no longer integral although the row is marked being integer)
9395 - slightly changed numerics in linear constraint handler presolving to fix a bug with coefficients detected to be scaled
9396 to an integral value, that are not integral after scaling due to a large scalar that increased the integrality gap to
9397 a value larger than epsilon
9399- Constraint handlers:
9400 - fixed bugs in consdataSwitchWatchedVars() of `or` and `and` constraint handlers
9401 - fixed wrong assertion in xor constraint handler with switching both watched variables to unwatched
9402 - fixed bugs in constraint handlers (and, logicor, or, setppc, xor) with calling conflict analysis during presolving
9403 - removed bug in knapsack constraint handler that appears if a variable is fixed to zero in knapsack presolving, which
9404 triggers a variable of the same knapsack to be fixed to one due to aggregation
9407 - removed bug in knapsack presolver
9408 - fixed bug in presolving with wrong number of newly fixed/aggregated/... variables/bounds/... after a restart
9410@section RN077 SCIP 0.7.7
9411*************************
9416- infeasible LPs in diving now produce conflict clauses (if LP conflict analysis is enabled)
9417- conflict analysis was slightly modified
9418- slightly changed aging strategy of logic or constraint handler
9423### Deleted and changed API methods
9425- method SCIPgetGap() and SCIPgetTransGap() now return infinity, if primal and dual bound have opposite sign (this
9426 removes the oddness with the gap increasing while the dual bound approaches zero)
9428### New API functions
9430- added methods SCIPgetVarsLogicor() and SCIPgetNVarsLogicor() in logic or constraint handler
9432### Changed parameters
9434- `lp/colagelimit` and `lp/rowagelimit` may now be set to -1 to disable deletion of columns/rows due to aging
9441- the file names in the archive file are now preceeded with a directory `scip-<version>/`
9442- the compiler is now also represented in the LP solver library names (e.g. you have to rename the softlink
9443 `libcplex.linux.x86.a` to `libcplex.linux.x86.gnu.a`)
9448- removed bug in conflict analysis that appears if the conflict is only active at the current depth level
9449- missing SCIPlpiIsPrimalFeasible() and SCIPlpiIsDualFeasible() implemented in lpi_spx.cpp and lpi_spx121.cpp
9450- removed preprocessing of linear constraint pairs with modifiable constraints
9453 - removed wrong assert `assert(eventfilter->len == 0 || eventfilter->eventmask != 0x00000000)` from event.c
9454 - removed wrong assert in conflict analysis (appeared on analyzing diving LP conflicts with both bounds of a non-binary variable changed)
9456@section RN076 SCIP 0.7.6
9457*************************
9462- creation of reconvergence clauses in conflict analysis
9463- first node of each plunging is not treated as plunging node w.r.t. calling primal heuristics
9464- improved performance of logic or constraint handler due to better watched variables handling
9469### Deleted and changed API methods
9471- changed SCIPcatchVarEvent() and SCIPdropVarEvent()
9472- SCIPstage() is now called SCIPgetStage()
9473- SCIPprintStatus() is now called SCIPprintStage()
9475### New API functions
9477- SCIPgetActivityLinear() in linear constraint handler
9478- SCIPgetFeasibilityLinear() in linear constraint handler
9479- SCIPchgVarBranchDirection()
9480- SCIPvarGetBranchDirection()
9481- SCIPgetStatus() returns the solution status
9482- SCIPprintStatus() outputs the solution status (beware, that the old SCIPprintStatus() method is now called SCIPprintStage())
9484### Changed parameters
9486- changed default frequency offset of pscostdiving `heuristics/pscostdiving/freqofs` to 2 and frequency offset of fracdiving
9487 `heuristics/feaspump/freqofs` to 0 in order to not call pscostdiving in root node, where nearly all pseudo costs are uninitialized.
9491- new parameter `separating/efficacynorm` to choose between Euclidean, maximum, sum and discrete norm in efficacy
9496- new possible result code `SCIP_DELAYED` for primal heuristics
9501- removed bugs in CLP Solver interface
9502- SCIP returned `gap limit reached` even if the problem was solved to optimality, if the optimal solution was found at a
9503 node with lower bound equal to the global lower bound
9504- after conversion of the focus node into a junction (e.g. in case of numerical troubles while solving the node's LP), the child
9505 nodes got the wrong LP fork attached (the common LP fork of the old and new focus node instead of the old focus node's LP fork)
9508 - bug reconvergence clauses in conflict analysis if bounds on non-binary variables were the reason for the fixing of the
9509 uip to create a reconvergence clause for
9510 - wrong sub calls in SCIPvarGet...CurrentRun() for aggregated variables
9511 - variables' conflict set counter was not reset when the problem was resolved again
9516- unbounded models lead to an error
9517- air04 and air05 return wrong optimal value (1 too large): possibly due to strong branching or setppc propagation?
9519@section RN075 SCIP 0.7.5
9520*************************
9525- started change log*/