9- fixed bugs with counting changes in presolving of nonlinear and setppc constraints, which resulted in negative values
10- cut off dead end node to correctly track dual bound update during solving
11- no longer construct and flush the LP in SCIPwriteLP() and SCIPwriteMIP() to avoid unexpected side effects
12- apply multi-aggregations before detecting redundancy in propagation of varbound constraints to keep bound implications
13- skip bound changes when cutting off a branch-and-bound subtree
14- correct detection of doublelex matrices and their handling via orbitope constraints
15- skip attempting to free transformed problem if SCIPtransformProb() failed with an error in SCIPpresolve(), since freeing
16 the transformed problem is likely to fail as well
17- fixed memory leak in primal heuristic "scheduler" when there is a restart
18- fixed stopping when there is a candidate with a change in the LP bound for both children in strong branching of branch_fullstrong
19- fixed detection of sinks in varbound detection from cumulative constraints
20- fixed memory allocation when adding strong SBCs for enclosing orbit of symmetric subgroups (disabled by default)
21- free paths of branch-and-bound tree iteratively instead of recursively to avoid stack overflow
22- fixed rare invalid memory access when collecting symmetry information for indicator constraints
23- recompute activity bounds before checking infeasibility and redundancy in linear constraint presolving
24- skip integer variables with fractional value in reference solution when finding additional variable fixings in ALNS heuristic
25- fix call of SCIPaddExprsViolScoreNonlinear() with constant expressions (no variables)
26- fixed bug with concurrent solve w.r.t. variable indices that led to segmentation faults and fix termination test
27- adjust further bounds before checking feasibility in SCIPvarAddVlb() and SCIPvarAddVub() to detect integrality cutoff
28- fixed that the last fixed binary variable was not set after binary variables were created for linking constraints
29- fixed that when a linking constraint with only one binary variable was added during solving, it was not disabled
30- fixed set_search_limits call when using SYM=sbliss with an old patched Bliss version
31
32Build system
33------------
34
35### CMake
36
37- added workaround for recent ctest versions rejecting -R -default as arguments
38
39### Makefile
40
41- added experimental target to run cppcheck
42
43
44@section RN923 SCIP 9.2.3
45*************************
46
47Fixed bugs
48----------
49
50- avoid hashmap key error in removal of doubletons and singletons in dual presolve of setppc constraints by skipping tripleton locks
51- when upgrading to xor constraint require parity variable to be enforced integral
52- provide the depth of the applied effective root with SCIPtreeGetEffectiveRootDepth() to avert invalid globalization of constraint set changes
53- disable objective limit during lexicographic dual minimization to preserve feasibility status
54- declare infinite bound inference infeasible in SCIPinferVarLbCons() and SCIPinferVarUbCons() to maintain correct loose LP values
55- fixed update of consssorted flags in a variable expressions data when adding an additional constraint using this variable
56- corrected computation of number of variables affected by symmetry
57- fixed computation of symmetry group size
58- correct comparison conditions in checkRedundancySide() of cons_varbound.c to ensure pair redundancy
59- also for the initial LP solve force acceptance of Farkas row in SCIPlpGetDualfarkas() if all other means for obtaining a reliable Farkas proof have failed
60- avoid overwriting the cutoff flag in tightenCoefs(), preprocessConstraintPairs(), and applyFixings() of cons_varbound.c to reject infeasible solutions
61- fix memory leak in CppAD interface w.r.t. user expressions
62- adjust bound before checking feasibility in SCIPvarAddVlb() and SCIPvarAddVub() to detect integrality cutoff
63- choose incumbent solution as reference in varFixingsRins() and varFixingsDins() of ALNS heuristic to ensure integrality
64- consider variable type in selectInitialVariableRandomly() of GINS heuristic to count integral variables
65- correct fractionality sign when standardizing bounds in simplifyInequalities() of cons_linear.c
66
67Build system
68------------
69
70### CMake
71
72- disable setting the boolean variable MACOSX_RPATH to a string value to actually enable @rpath usage
73- define SOPLEX_NEEDED and ZIMPL_NEEDED to avoid syntax error in configuration file
74
75Miscellaneous
76-------------
77
78- when writing a problem with non-generic names, warnings are printed if variable or constraint names are not unique
79
80@section RN922 SCIP 9.2.2
81*************************
82
83Fixed bugs
84----------
85
86- fixed definition of slack variables of >= constraints and ranged rows in LP interface to Gurobi
87- free memory leaking singleton arrays for ignored variables in SCIPapplyHeurDualval()
88- use epsilon tolerance for bound implications of dual substitutions in dualPresolve() of cons_linear
89- fixed timeouts due to race conditions when using TPI=omp
90- fixed issues with indexing of concurrent solvers when a solver finishes (because SCIP is too fast) before others have been created when using TPI=tny
91- respect fixing if variable is declared binary in bounds section of mps file
92- fixed reading mps files with short row and column names and some fixed-form mps files with spaces in row names
93- force local bounds to adjusted value when fixing variable
94- adds missing NULL check for Benders' subproblems in feasalt cut
95- apply objective scale to pseudoboolean non-linear terms
96- impose pseudoboolean cost bound without intermediate casting
97- flatten aggregation graph before finishing presolve to accelerate evaluating an empty solution
98- respect fixed resultants in binvarGetActiveProbindex() of branch_relpscost
99- drop fixed resultants when copying pseudoboolean constraint
100- correct matrix entry when resolving aggregated variables in checkSystemGF2() of cons_xor
101- corrected symmetry detection graph of cons_and, cons_or, cons_xor, and cons_indicator
102- correct redundancy filter in consdataCreateRedundant() of cons_bounddisjunction
103- replaced unreliable comparison of node pointers by node numbers in prop_genvbounds
104- allocate memory for all integral variables in applyCliqueFixings() of heur_clique
105- fix conflict resolution for one particular case in cons_indicator
106- make interface to nauty thread safe
107- use relative epsilon tolerance to check Farkas row in SCIPlpGetDualfarkas() to avoid invalid cutoff
108- fixed bug with SOS2 constraints of size that avoided a correct enforcing
109
110Build system
111------------
112
113### Cmake
114
115- allow to set HIGHS_DIR via -D flag as well
116- reenable building and testing of SCFLP example
117- fixed that compiler flags for sanitizers were not used for compiling objects of SCIP library
118- prioritize local includes for unittests, examples, and applications to link the intended SCIP version
119- fix detection of Gurobi 11 and 12 libs on Linux
120
121### Makefile
122
123- fix use of SANITIZE=full for debug builds with GCC on Linux: removed -fsanitize=leak because it cannot be used together with -fsanitize=address
124- fix that make install SHARED=true missed to install libscipbase
125
126@section RN921 SCIP 9.2.1
127*************************
128
129Fixed bugs
130----------
131
132- apply same feasibility definition in PaPILO as in SCIP to avoid numerical inconsistencies
133- check variable cancellation in SCIPvarAddVlb() and SCIPvarAddVub() to avert wrong infeasibility
134- SCIPfreeReoptSolve() now also clears partial solutions
135- fixed bug in calculation of "fractionality score" for spatial branching candidates in cons_nonlinear
136- fixed bug with installing symmetry dialog in sub-SCIPs
137- added copy callbacks for presolvers dualagg and redvub, branching rules lookahead and cloud, primal heuristics dualval and repair, propagator nlobbt, and separators gauge and convexproj
138- respect maximal separation rounds setting by running remaining delayed separators in last round
139- replace terms consistently in applyFixings() of cons_linear to handle infinite aggregations
140
141Build system
142------------
143
144### Cmake
145
146- fix SCIP Optimization Suite build with -DSYM=(s)bliss and bliss being downloaded and built during configuration by cmake
147- fix use of a bliss cmake installation (from https://github.com/scipopt/bliss) specified via BLISS_DIR if -DSYM=(s)bliss
148
149### Makefile
150
151- the check/solchecker build can now use also GMP installations by Homebrew on macOS/arm64
152
153Miscellaneous
154-------------
155
156- the output precision for writing CIP/OPB files has been increased at several places for nonlinear constraints
157- the solchecker tool now also supports SCIP solutions without unknown or infinite values
158- generate an error if the same linear constraint is used by several indicator constraints
159
160@section RN920 SCIP 9.2.0
161*************************
162
163Features
164--------
165
166- added check for absolute and relative gap limits at end of synchronization in concurrent solving mode, in order to terminate earlier;
167 note that if the concurrent solve is stopped due to a gap limit, the "winner" solver will have an interrupted solution status and
168 its primal and dual bounds may not be the best possible ones (use SCIPgetConcurrentPrimalbound() and SCIPgetConcurrentDualbound() instead)
169- parse pseudoboolean constraint from CIP format (and add linear-"and"-reformulation)
170
171Performance improvements
172------------------------
173
174- reoptimization now also stores propagations from propagators if reoptimization/saveconsprop is enabled;
175 the parameter will be renamed to reoptimization/saveprop in a next major release
176- imposed stricter limits on the size of disconnected components which may be solved separately during presolve
177- use individual slack variables also for constraints indicated by a common binary variable to use tighter formulation by default
178- when computing symmetries using Nauty, iteration limits are now available to terminate Nauty early
179
180Fixed bugs
181----------
182
183- Benders' decomposition subproblems that are always infeasible are correctly handled and the complete problem is declared infeasible
184- skip linear constraint propagation if the residual activity bound cancels the side precision
185- correct bound tracking to make the evaluation of primal-dual-integrals work
186- skip aggregations on fixed variables in milp presolver to avoid errors for earlier versions of PaPILO
187- use indices of negation counterparts and accept fixings when ordering and-resultants of pseudoboolean constraints
188- update locks on model variables before removing pseudoboolean constraints in presolve
189- reformulate soft pseudoboolean constraints with linear constraints if the indicator decomposition is disabled
190- add workaround for recent HiGHS versions resetting the model status when changing the presolve option after a solve
191- 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
192
193Interface changes
194-----------------
195
196### New API functions
197
198- added SCIPtpiIsAvailable() to check whether a working task processing interface is available (TPI != none)
199- added SCIPtpiGetLibraryName() and SCIPtpiGetLibraryDesc()
200- SCIPdelCons() can now also be called in SCIP_STAGE_TRANSFORMED
201- added SCIPstrcasecmp() and SCIPstrncasecmp() for case-insensitive string comparison
202- added SCIPbendersSubproblemsAreInfeasible() to return if at least one subproblem has been identified as being
203 infeasible prior to performing any variable fixing
204
205### New parameters
206
207- presolving/milp/abortfacexhaustive to control the abort threshold for exhaustive presolving in PAPILO
208- presolving/milp/abortfacmedium to control the abort threshold for medium presolving in PAPILO
209- presolving/milp/abortfacfast to control the abort threshold for fast presolving in PAPILO
210- constraints/components/maxcompweight to determine the maximum weight for a disconnected component that is solved during presolve
211- constraints/components/contfactor counts the contributing factor of a single continuous variables with respect to the weight limit specified by constraints/components/maxcompweight
212- constraints/indicator/usesameslackvar to decide whether the same slack variable should be used for indicators constraints with common binary variable
213- propagating/symmetry/nautymaxncells and propagating/symmetry/nautymaxnnodes to set iteration limits in Nauty (only available if build with SYM=nauty or SYM=snauty)
214
215### Changed parameters
216
217- presolving/milp/threads is now only available if PaPILO is built with TBB
218- changed default of numerics/recomputefac to 1e+6 to aim at relative epsilon precision
219
220Build system
221------------
222
223### Cmake
224
225- attempted to fix detection of CPLEX library on macOS and Windows systems
226
227Testing
228-------
229
230- added parameter FILTER for tests/Makefile to run only tests with a specific pattern (ctest with -R FILTER)
231
232Miscellaneous
233-------------
234
235- adjusted Gurobi interface for Gurobi 12
236- reordered events: BESTSOLFOUND/NODE_FEASIBLE are now processed before the nodes are cut off and before NODE_DELETE events are processed
237- removed `#define` of `getcwd` (in case of Windows builds) in scip/def.h
238- the `#define` of `strcasecmp` and `strncasecmp` (in case of Windows builds) in scip/def.h will be removed with SCIP 10;
239 use `SCIPstr(n)casecmp()` (scip/pub_misc.h) instead
240
241@section RN911 SCIP 9.1.1
242*************************
243
244Fixed bugs
245----------
246
247- fix bug in separator aggregation that caused incorrect terminations when for an integral objective the objective limit was set to a fractional value
248- fix bug in memory management of doublelex matrices where indices were set beyond array bounds
249- store relevance flags in consdataTightenCoefs() of cons_linear.c to avoid dropping variables unintentionally due to numerical changes
250- fix possible segmentation fault when resetting local and global bounds of original variables after abnormal termination
251- compare coefficient scales to detect parallelism to avoid integral relaxations in detectRedundantConstraints() of cons_linear.c
252- remove coefficient information from linear constraint hashes in order to compare keys with tolerances
253- fixed NULL pointer dereference in SCIPtpiGetNumThreads() of TinyCThread interface if called before SCIPtpiInit(); now returns 0 in this case
254- calling SCIPsolveConcurrent() when SCIP was compiled without a TPI now results in a plugin-not-found error
255- fixed LPI status functions of lpi_cpx if the barrier is called
256- check cuts for redundancy after scaling in cutTightenCoefs() and cutTightenCoefsQuad() of cuts.c
257- maintain definition of artificial integral variables in xor constraints to avoid invalidation of conflict constraints
258- free childless nodes only after the deactivation of the old focus path in treeSwitchPath() of tree.c
259- only normalize rows for column norm evaluations in shift-and-propagate heuristic to avoid unscaled violations
260- 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
261- check for more data to be freed before modifying nonlinear constraints in SCIPaddExprNonlinear()
262- allow for terms with zero coefficients when checking sum in SCIPexprCheckQuadratic()
263- do not abort writing of constraints to lp/pip files (and forget to free buffer memory) when encountering unsupported nonlinear constraint
264- fixed that strings with names and descriptions of the LPI's were not null-terminated
265- fixed decision on when to enforce nonlinear constraints on relaxation solutions if integer variables are present
266- fixed reading of very long lines (>78000 characters) in FlatZinc reader
267- 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)
268- keep epsilon coefficients in applyFixings() of cons_linear.c until multiples are merged to avoid loss of relevant contributions
269- fixed that some variable type changes were not accounted correctly in presolve of linear constraints
270- fix constraint sorting in setpp-orbitope upgrade in symmetry code
271- fixed that SCIPnodeGetConsProps() also counted bound changes from propagators
272- use original and-constraints of an untransformed pseudoboolean constraint when copying original problems to avert segmentation faults
273- sort and-constraints of a pseudoboolean constraint with respect to the resultant problem indices to avoid shuffled copies
274- treat pseudoboolean constraints as nonlinear constraints in OPB reader to prevent duplication mistakes
275
276Examples and applications
277-------------------------
278
279- in example Binpacking implement Farkas pricing for packings because branching can actually lead to infeasible restricted master LPs
280
281Testing
282-------
283
284- allow unknown parameters to let tests pass if only optional dependencies are missing
285
286Build system
287------------
288
289### Cmake
290
291- 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`
292- extended identification of Ipopt library on Windows to also look for ipopt.dll.lib, as this is used since Ipopt 3.13.0 (2019)
293
294
295@section RN910 SCIP 9.1.0
296*************************
297
298Features
299--------
300
301- added constraint handler that checks and enforces bounds on original variables which have been fixed or aggregated in the transformed problem
302- allow for implicit integer variables in xor constraints
303- implemented symmetry detection callbacks for pseudoboolean constraints
304- added option to consider enforcement of nonlinear constraints (including spatial branching) before integrality has been enforced
305
306Fixed bugs
307----------
308
309- make sure that, in dual proof analysis, upgraded constraints can report their number of variables
310- check knapsack constraints as linear constraints to avoid violations based on implicit integrality
311- make sure that symmetry detection callbacks report success
312- make arithmetics in cuts.c more robust to avoid invalid scg cuts due to numerical rounding sensitivity
313- allow to copy pseudoboolean constraints even if no AND constraints are present in order to avoid a warning
314- set value for variable that is introduced to reformulate nonlinear objective function when reading .nl files with initial solution
315- fixed that multi-aggregations from PaPILO were accepted without ensuring that their bounds hold
316
317Examples and applications
318-------------------------
319
320- TSP: removed `gzstream.h/hpp` and parse gzipped files differently
321
322Interface changes
323-----------------
324
325### New callbacks
326
327- SCIP_DECL_NLHDLRENFO takes additional parameter branchcandonly to indicate whether only branching candidates should be registered,
328 without looking for cuts or boundchanges
329
330### New API functions
331
332- new function SCIPgetExprActivityNonlinear() to get activity of nonlinear constraint
333- new function SCIPincludeConshdlrFixedvar() to include new constraint handler that checks bounds on fixed original variables
334
335### New parameters
336
337- 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)
338- limits/dual to terminate the solve as soon as the dual bound is at least as good as this value
339- presolving/milp/internalmaxrounds to control the maximal rounds for each call of the milp presolver (PaPILO)
340- constraints/fixedvar/∗ to control the new constraint handler that checks bounds on fixed original variables
341- constraints/nonlinear/branching/mixfractional to specify minimal average pseudo cost count for discrete variables
342 at which to start considering spatial branching before branching on fractional integer variables
343 (default infinity means that integrality is always enforced before nonlinear constraints)
344- constraints/nonlinear/branching/fracweight to specify weight of fractionality of integer variables in spatial branching
345
346### New data structures
347
348- enum SCIP_Status has been extended by SCIP_STATUS_PRIMALLIMIT and SCIP_STATUS_DUALLIMIT to indicate termination at limits/primal and limits/dual respectively
349
350Build system
351------------
352
353- changed the default symmetry computation package from sassy+bliss to sassy+nauty
354- bliss source is no longer included in the source tree, but can be linked as external library (https://github.com/ds4dm/Bliss)
355- cmake now automatically downloads and installs the latest release version of SoPlex from GitHub if it is not found directly
356
357Miscellaneous
358-------------
359
360- updated nauty to version 2.8.8
361
362
363@section RN901 SCIP 9.0.1
364*************************
365
366Fixed bugs
367----------
368
369- fixed bug in detection of double lex matrices due to wrong memory allocation
370- fixed bug where parameter `limits/objectivestop` was copied to subscips in plugins which have different objectives
371- in count mode respect empty solution when problem is solved in presolving
372- fixed that SCIP may have tried to pass a negative random seed to an LP solver
373- fixed bug where conflict analysis in strong branching tried to analyze an unsuccessful LP solve
374- enable parameter limits/restarts by allowing to reach the restart limit in restartAllowed()
375- handle normalizing linear constraints in presolving with more caution to avoid numerical difficulties for integer variables with large coefficients
376- use quad precision to calculate residual activity bounds to reduce numerical errors for large variable bounds in cons_linear.c
377- in SCIPsolveProbingLP() when objective has been changed do not return cutoff due to exceeding the cutoff bound
378- set probing LP to be a relaxation only when objective has not been changed
379- declare contradicting infinities in getMinActivity() and getMaxActivity() as non-tight
380- reject farkas solution with large values to bound magnification of errors in SCIPgetFarkasProof()
381- if all variables are fixed, apply relative feasibility tolerance to avoid invalid infeasibility in applyFixings() of cons_linear.c
382- delete empty redundant knapsack and linear constraints after cleanup in SCIPmatrixCreate()
383- cleanup first constraints in SCIPcleanupConssVarbound(), SCIPcleanupConssSetppc(), and SCIPcleanupConssLogicor()
384- symmetry handling methods have not been added immediately after computing symmetries, which has been fixed
385- delay checking node limits after presolving to correctly continue up to the exceeding main node
386- simplified the objective sense assumption for the subproblems in the Lagromory separator
387- update effective root depth iteratively to avoid trapping it at a single child node
388- fixed that dualsparsify presolver did not always check do-not-multiaggregate variable flag
389- fixed bug in computing elements of orbits in orbital reduction
390
391Miscellaneous
392-------------
393
394- redefine isrelax to istight in cons_linear.c
395
396Build system
397------------
398
399### Cmake
400
401- A file cmake.log containing the changed options is written to the cmake build directory.
402- removed replacement of the settings of RelWithDebInfo
403- add compile option -ffp-contract=off or /fp:precise to enhance reproducibility across different systems
404
405### Makefile
406
407- add flags -ffp-contract=off and /fp:precise to enhance reproducibility across different systems
408
409Interface changes
410-----------------
411
412### New parameters
413
414- added parameter "propagating/symmetry/symtiming" to determine when symmetries are computed and handled
415
416### Changed parameters
417
418- Disabled "propagating/symmetry/addconsstiming" since it is not used anymore.
419- Disabled "propagating/symmetry/ofsymcomptiming" since it is not used anymore.
420
421@section RN900 SCIP 9.0.0
422*************************
423
424Features
425--------
426
427- added simplification of abs(x)^n to x^n when n is even (simplify rule POW12)
428- in expression simplification, added possibility to expand power of sum with exponents larger than 2 (simplify rule POW7)
429- in expression simplification, added possibility to expand products with sums as factor when there are more than two factors (simplify rule SP12b)
430- in expression simplification, added possibility to allow expanding power of products with fractional exponent (simplify rule POW5a)
431- can now build with Lapack (used for solving nonlinear problems) explicitly; if IPOPT is used, then Lapack is accessed through it;
432 an interface to Lapack is available in lapack_calls.h
433- added support for logical constraints in binary variables and basic logical operators (and, or, not, equal) to AMPL .nl reader
434- indicator constraints now use the same slack variable for the linear constraints if binary variables are used multiple times
435 for indicator constraints
436- new diving heuristic indicatordiving that focuses on indicator variables which control semicontinuous variables
437- updated statistics on NLP relaxation; information on convexity of NLP has been added
438- added new bandit method (EXP.3-IX) that is the new default of the ALNS heuristic
439- added dialog to display recognized permutation symmetries ("display symmetry")
440- The symmetry detection code has been completely restructured. Instead of completely encoding symmetry information in
441 prop_symmetry.c, there is a new callback for constraint handlers, which returns symmetry relevant information by
442 encoding a constraint as a node and edge colored graph. This way, also custom constraint handlers can provide
443 symmetry information.
444- added special presolving step for logicor and set covering/packing for constraints with two variables and one independent variable
445- 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
446- added new cut selector plugin called cutsel_ensemble. Performs a superset of hybrid cutsel. Implements new filtering methods and scoring options.
447- added new branching rule based on Gomory mixed-integer cuts
448- added new branching score to the reliability pseudo-cost branching rule
449- added new cut selector plugin called cutsel_dynamic. Performs a superset of hybrid cutsel. Implements new filtering methods and scoring options.
450- added monoidal strengthening to intersection cut generation of nlhdlr_quadratic
451- extended heuristic dps to run after processing the node and to use strict limits for the reoptimization step
452- extended obbt propagator to handle variables of the linear constraints corresponding to indicator constraints
453- added new heuristic heur_scheduler that models the selection of LNS and diving heuristics as a multi-armed bandit problem
454- added nonlinear handler for signomial expressions: adds cuts based on a difference of convex functions representation
455- 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.
456- added a new separator sepa_lagromory to generate Lagromory cuts in a relax-and-cut framework, i.e., GMI cuts generated
457 at different bases that are explored in the process of solving the Lagrangian dual problem at a node. This separator
458 is OFF by default.
459- when parsing nonlinear constraints from CIP files, the * after the number in a term is now optional if followed by a variable,
460 i.e., instead of 3*<x>*<y>, now also 3<x>*<y> can be read, but 3<x><y> is not supported;
461 this allows to read some CIP files that were written with SCIP < 8
462- when running bliss, we now limit the number of actually created generators and not the ones considered by bliss
463
464Performance improvements
465------------------------
466
467- Variable conflict-based addition of Schreier-Sims cuts for symmetry handling in prop_symmetry.c does no longer use
468 an expensive explicit conflict graph construction.
469- Only run propagation of indicator constraints if relevant variables have changed.
470- Propagation of indicator constraints propagates maximal activity of linear constraint to upper bound of slack variable.
471- Added initialization of LP relaxation for SOC constraints.
472- Avoided some numerical issues when separating SOC constraints.
473- If differentation of convex expression fails in convex nlhdlr, then a perturbed point is tried.
474- Use sassy/bliss as default symmetry computation package.
475- No longer linearize indicator constraints in undercover heuristic by default.
476- Deactivate pre-root heuristic zeroobj in undercover heuristic.
477- Added new branching score tiebreaker for reliability pseudo-cost branching rule
478- Try nearest bound if zero solution value is out of bounds in heuristic trivial.
479
480Interface changes
481-----------------
482
483### New and changed callbacks
484
485- Added solution linearization callback for nonlinear handlers.
486 The nonlinear handler may use this callback to add tight cuts that use the given solution as reference point to the cutpool.
487 The callback is called if option constraints/nonlinear/linearizeheursol is enabled.
488- The callback for copying problem data SCIP_DECL_PROBCOPY() now has a parameter "original" indicating whether the original
489 or transformed problem should be copied. Similarly, SCIPprobCopy() in prob.h/c has such a parameter.
490- Added CONSGETPERMSYMGRAPH and CONSGETSIGNEDPERMSYMGRAPH callback for constraint handlers, which provides symmetry information about constraints to SCIP.
491
492### Deleted and changed API methods
493
494- SCIPtpiInitLock(), SCIPtpiDestroyLock(), SCIPtpiInitCondition(), SCIPtpiDestroyCondition() now take a double
495 pointer to SCIP_LOCK/SCIP_CONDITION, respectively.
496- Renamed SCIPtpiSumbitJob() to SCIPtpiSubmitJob().
497- SCIPcreateConsIndicatorLinCons(), SCIPcreateConsIndicatorGenericLinCons() do not allow binvar to be NULL anymore
498- Replaced SCIPnlrowSetCurvature() by SCIPsetNlRowCurvature().
499- SCIPsnprintf() now returns the required string length in case reallocation is necessary.
500- SCIPcomputeCoverUndercover() receives three more arguments which nonlinearities to cover
501- removed definition of SQRT
502- SCIPincludeObjConshdlr(), SCIPincludeConshdlr(), SCIPconshdlrCreate() receive two more arguments for the
503 conshdlr callbacks CONSGETPERMSYMGRAPH and CONSGETSIGNEDPERMSYMGRAPH
505- new parameter issigned for SCIPcomputeOrbitsSym()
506- new parameter symtype for SCIPcomputeComponentsSym()
507- new parameter symtype and permvardomaincenter for SCIPlexicographicReductionAddPermutation()
508- replaced parameters matrixdata and exprdata of SYMcomputeSymmetryGenerators() by graph
509
510### New API functions
511
512- new functions for interfacing with Lapack: SCIPlapackIsAvailable(), SCIPlapackIsAvailable(), SCIPlapackComputeEigenvalues(), and SCIPlapackSolveLinearEquations
513 These functions should be used instead of SCIPisIpoptAvailableIpopt(), SCIPcallLapackDsyevIpopt(), and
514 SCIPsolveLinearEquationsIpopt() in the context of computing eigenvalues or solving linear equations.
515 If IPOPT is available, the calls will be passed on to Ipopt's interface to Lapack.
538- SCIPincludeCutselEnsemble(), SCIPselectCutsEnsemble() to include cutsel_ensemble or use the selection algorithm
539- SCIPincludeBranchruleGomory() includes new gomory cut based branching rule
540- SCIPgetVarAvgGMIScore(), SCIPincVarGMISumScore(), SCIPgetVarLastGMIScore(), SCIPsetVarLastGMIScore() set historical values used by SCIP's default branching rule
541- SCIPincludeNlhdlrSignomial() includes the signomial nonlinear handler
542- SCIPgetExprMonomialData() returns a monomial representation of a product expression
543- SCIPestimateRoot() computes estimators for roots with exponent in [0,1]
544- SCIPincludeCutselDynamic(), SCIPselectCutsDynamic() to include cutsel_dynamic or use the selection algorithm
545- SCIPincludeSepaLagromory() to include the new Lagromory separator
546- SCIPconsCompCheck() to compare two constraints based on their check priority
547- SCIPgetConsPermsymGraph() and SCIPgetConsSignedPermsymGraph() to access the (signed) permutation symmetry detection graph of a constraint
548- SCIPsetConshdlrGetPermsymGraph() and SCIPsetConshdlrGetSignedPermsymGraph() to set the (signed) permutation symmetry detection graph of a constraint
549- SCIPconshdlrSupportsPermsymDetection() and SCIPconshdlrSupportsSignedPermsymDetection() to access whether a conshdlr supports detection of (signed) permutation symmetries
550- new API functions for creating and manipulating a symmetry detection graph: SCIPcreateSymgraph(), SCIPfreeSymgraph(), SCIPcopySymgraph(), SCIPextendPermsymDetectionGraphLinear(),
582 String values should not be quoted and spaces in string values are not supported.
583- sassy can be used now as preprocessor for nauty/traces
584- The solution status codes written to AMPL solution files now match those from https://mp.ampl.com/details.html#_CPPv4N2mp3sol6StatusE.
585
586### Changed parameters
587
588- change default value of parameter separating/filtercutpoolrel to FALSE
589- Shrunk range of parameter "propagating/symmetry/sstleaderrule" from [0,3] to [0,2], removed "MAXCONFLICTS"-option.
590- 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).
591- Disabled "propagating/symmetry/symfixnonbinaryvars" since it is not used in the new symmetry code.
592- Replaced "propagating/symmetry/onlybinarysymmetry" with "propagating/symmetry/enforcecomputesymmetry" and set to FALSE by default.
593- Disabled "propagating/symmetry/performpresolving" since running orbital reduction during presolving is not effective.
594- Repurposed "propagating/symmetry/usedynamicprop" since it now also applies to lexicographic reduction.
595- Changed default value of parameter "propagating/symmetry/addsymresacks" from FALSE to TRUE.
596
597### New parameters
598
599- separating/maxcutsgenfactor and separating/maxcutsrootgenfactor as factors (w.r.t. separating/maxcuts and
600 separating/maxcutsroot) for limits on the number of cuts generated (which used to be constants '2')
601- expr/pow/expandmaxexponent to specify limit on exponent when to expand power of sum
602- expr/pow/distribfracexponent to enable expanding power of products with fractional exponents
603- expr/product/expandalways to enable expanding any product with sums as factor (that is, also when more than two factors)
604- nlhdlr/convex/maxperturb to specify maximal perturbation of non-differential reference points
605- benders/default/nlpiterlimit to adjust iteration limit for NLP solver for Benders' decomposition NLP subproblems
606- limits/objectivestop to interrupt the solve as soon as a primal solution is found
607 that is at least as good as the given value
608- heuristics/undercover/{coverand,coverind,covernl} to control which nonlinearities to consider (by default only "and" and nonlinear constraints)
609- cutselection/ensemble/∗ all parameters for new ensemble cut selector
610- cutselection/dynamic/∗ all parameters for new dynamic cut selector
611- branching/relpscost/gmiavgeffweight specifies the weight in the relpscost branching score of the normalized efficacy of all generated GMI cuts (for a variable)
612 branching/relpscost/gmilasteffweight specifies the weight in the elpscost branching score of the normalized efficacy of the last generated GMI cut (for a variable)
613- nlhdlr/quadratic/usemonoidal to enable monoidal strengthening when separating quadratics with intersection cuts
614- nlhdlr/quadratic/trackmore to collect more statistics for monoidal strengthening when separating quadratics with intersection cuts
615- nlhdlr/quadratic/useminrep to use the minimal representation to compute cut coefficients when separating quadratics with intersection cuts
616- nlhdlr/quadratic/sparsifycuts to enable sparsification of intersection cuts for quadratics
617- heuristics/dps/reoptlimits to set strict limits for the reoptimization step in dps
618- heuristics/dps/timing to run dps after processing the node
619- heuristics/scheduler/∗ all parameters for new scheduler heuristic
620- nlhdlr/signomial/enabled, nlhdlr/signomial/maxnundervars, nlhdlr/signomial/mincutscale: parameters for the signomial nonlinear handler
621- separating/lagromory/freq to denote the frequency for calling Lagromory separator
622- separating/lagromory/away to denote the minimal integrality violation of a basis variable to try separation
623- separating/lagromory/dynamiccuts to denote whether the generated cuts be removed from LP if they are no longer tight
624- separating/lagromory/maxroundsroot to denote the maximal number of separation rounds in the root node
625- separating/lagromory/maxrounds to denote the maximal number of separation rounds in a non-root node
626- separating/lagromory/nmaxcutsperlproot to denote, in the root node, the maximal number of Lagromory cuts that can be
627 separated per explored basis of the Lagrangian dual
628- separating/lagromory/nmaxcutsperlp to denote, in a non-root node, the maximal number of Lagromory cuts that can be
629 separated per explored basis of the Lagrangian dual
630- separating/lagromory/perroundnmaxlpiters to denote the maximal number of separating LP iterations that are allowed per
631 separation round
632- separating/lagromory/dualdegeneracyratethreshold to denote the minimum dual degeneracy rate for the separator execution
633- separating/lagromory/varconsratiothreshold to denote the minimum variable-constraint ratio on the optimal face for the
634 separator execution
635- many other advanced parameters for the Lagromory separator, which are also mentioned under separating/lagromory/∗
636
637### Data structures
638
639- new data structure SYM_GRAPH to encode symmetry information from a constraint
640- new data structure SYM_EXPRDATA to encode symmetry information from expressions
641- replaced enum SYM_SYMTYPE by a complete new one; removed SYM_RHSSENSE, added SYM_NODETYPE and SYM_CONSOPTYPE
642
643Deleted files
644-------------
645
646- 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
647
648Unit tests
649----------
650
651- new unittests for nlhdlr_quadratic that test monoidal strengthening and the use of the minimal representation to compute cut coefficients
652- unittests for nlhdlr_signomial
653
654Testing
655-------
656
657- changed `set lim obj` to `set lim objective` in ctest since `obj` is no longer unambiguous
658
659Build system
660------------
661
662### Cmake
663
664- New flag -DLAPACK=on for linking with Lapack (must be available in the system)
665- added flag option "SYM=sbliss" for using sassy/bliss as a graph automorphism package
666- use SYM=sbliss by default, since sassy and bliss are now shipped with SCIP.
667- added flag option "SYM=snauty" for using sassy/nauty as a graph automorphism package
668
669### Makefile
670
671- added flag option "nauty" for SYM variable to specify which graph automorphism package should be used
672- added flag option "sbliss" (sassy/bliss) for SYM variable to specify which graph automorphism package should be used
673- added flag option "snauty" (sassy/nauty) for SYM variable to specify which graph automorphism package should be used
674- use SYM=sbliss by default, since sassy and bliss are now shipped with SCIP
675- New flag LAPACK for linking with Lapack (must be available in the system)
676- A file scip/config.h is created in the build directory ($(OBJDIR)/include) now.
677 Defining NO_CONFIG_HEADER is no longer necessary and has no effect anymore.
678
679Fixed bugs
680----------
681
682- Number of runs in which separation is enabled will now be correct as per "separating/maxruns" parameter. Earlier,
683 separation was enabled for "maxruns + 1" number of runs, i.e., separation was enabled even when "maxruns = 0" was set.
684- add safeguard for number of selected cuts
685- use double double precision for delta in activity updates of cons_linear.c
686- sort constraints in checkSolOrig() to keep the logic of constraint handlers intact
687- fixed make install when SHARED=no and make uninstall
688- check absolute coefficients relative to extremal average to avoid invalid unifications in normalizeCons()
689- enforce and check symmetry-based constraints to take their locks (in dual reductions) into account
690- flush changes at the end of SCIPlpiSetBase() in lpi_grb.c to apply the newly set basis correctly
691
692Miscellaneous
693-------------
694
695- The TPI has been changed to become mostly independent from the actual parallel interface during compile time.
696 For this, the locks and conditions are now pointers to abstract structs.
697- fixed that scip/def.h, the header for C preprocessor definition (`#define`'s), included headers for some SCIP type and function definitions
709- fixed that scaling of rows in Gurobi interface (SCIPlpiScaleRow()) changed infinite sides to large finite ones (1e20) when scale factor is negative
710- check whether objective limit is truly reached in SCIPlpiIsStable()
711- if an objective limit is set and Mosek claims that it is exceeded, check that this is indeed the case in SCIPlpiIsStable()
712- the .mps file reader was extended to additionally accept .mps files with the objective sense section on one line
713- ensure that delayed cutpool separation does not happen if enough cuts have been found already
714- 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
715- 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
716- fixed memory leak in branching rule "distribution"
717- 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
718- fixed two bugs in cons_varbound: avoid adding variable bounds if vbdcoef is infinite and unlock/lock variables if lhs/rhs/vbdcoef are changed
719- 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
720- fixed error when attempting to copy SCIP with activated pricers
721- 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
722- updated and, or, and pseudoboolean constraint handlers to better handle fractional implicit integer variables in enforcement
723- 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
724- add missing row links to columns in SCIPflushRowExtensions() required to maintain correct row norms
725- restrict separator intobj to solutions for which there can be no better feasible integral objective values to avoid cutting them off
726- delay removal of clique lists from SCIPvarRemoveCliquesImplicsVbs() into cliqueCleanup() to avoid segmentation faults by incomplete cleanups after variable conversions
727- reject sub-solutions with invalid objectives in SCIPtranslateSubSols() due to contradicting infinite contributions
728- correct column index in getMinMaxActivityResiduals() to make presolver dualinfer work
729- copy quiet flag from main scip's message handler to the one of solverscip in concurrent optimization
730- avoid bound tightening cycles towards huge redundancy bounds in fullDualPresolve() to avert fatal numerical trouble in representing vertices of linear relaxations with unbounded domains
731- fix problem where debug solution did not work if branching constraints are present
732- update index of dominating variable on coefficient deletion in dualPresolving() of constraint handler logicor
733- pass on flags from a redundant to the implying varbound constraint in preprocessConstraintPairs() to avoid suboptimal fixings by model relaxations
734- apply reductions of dualinfer only if a dual solution exists (primal is bounded)
735- before presolving is finished check solutions before retransforming them including tiny values to keep check flags consistent
736- 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
737- correct local flag of singleton conflict constraints in tightenSingleVar() against invalid bound globalization
738- respect unboundedness in the computation of activity bounds in conflict.c to avoid invalid huge bounds due to small coefficients on unbounded variables
739- ensure positive sides of a linear constraint when recognizing a set partition in rangedRowSimplify() to account for redundancy issues
740- relax numerical conditions for variable aggregations to avert invalid variable fixings
741- fixed harmless read of uninitialized data when creating parameters
742- fix call of SCIPnlpiOraclePrintProblem in nlpi_worhp
743
744Performance improvements
745------------------------
746
747- Use sassy/bliss as default symmetry computation package.
748
749Interface changes
750-----------------
751
752### Interfaces to external software
753
754- added interface to nauty/traces for symmetry computation
755- added interface to sassy, a preprocessor for symmetry computation
756- The directory src/sassy contains the source code of sassy.
757
758Build system
759------------
760
761### Cmake
762
763- added flag option "SYM=sbliss" for using sassy/bliss as a graph automorphism package
764
765### Makefile
766
767- added flag option "nauty" for SYM variable to specify which graph automorphism package should be used
768- added flag option "sbliss" for SYM variable to specify which graph automorphism package should be used
769- use SYM=sbliss by default, since sassy and bliss are now shipped with SCIP
770
771Miscellaneous
772-------------
773
774- the parameter change callback is no longer called at the moment a parameter is created
775
776@section RN804 SCIP 8.0.4
777*************************
778
779Features
780--------
781
782- use quad precision in cutsSubstituteMIR() for substituting slack variables into CMIR cuts
783- use quad precision for activity computations in cons_linear.c
784
785### Deleted and changed API methods
786
787- SCIPshrinkDisjunctiveVarSet() no longer attempts to cutoff the current node if it finds the
788 given disjunction to be infeasible; it is now in the responsibility of the caller to act accordingly
789
790### New API functions
791
792- added SCIPskipSpace
793- added XML parser routines from src/xml/xml.h
794
795### Interfaces to external software
796
797- updated XPRESS interface to work with XPRESS 41 as well
798- new interface to LP solver HiGHS (lpi_highs.cpp)
799
800### Changed parameters
801
802- changed integer parameter "propagating/symmetry/recomputrestart" from range {0, 1, 2} to being fixed at value 0
803
804Unit tests
805----------
806
807- added new checks for objective, bounds and sides inside the scaling tests in lpi/change.c
808
809Fixed bugs
810----------
811
812- relax condition of assert in lpSolve to hold only if lp/checkstability is true
813- OPB reader: dynamically increase the size of the line buffer for reading in getMaxAndConsDim()
814- Enabled the solution limit checks in SCIPsolveIsStopped in solve.c when in SCIP_STAGE_PRESOLVING
815- fix quad precision comparison for the calculation of knapsackcover constraints.
816- force copying of symmetry constraints for concurrent solve
817- increase the precision of double multiplications in quad precision environments
818- corrected handling of different variable types in symmetry
819- orbitope detection: refine computation of overlap structure and fixed bug in finding orbitope generators
820- ensure that winner is always determined in concurrent mode
821- when a row with invalid index range is added to the global cutpool, update the indices instead of failing with an assert
822- update of watched literals in cons_xor.c and ensure that fixed variables are counted in propacateCons()
823- avoid some numerical issue in check for redundant variables in linear constraints (introduced with version 8.0.2)
824- more rows are treated as being integral in cutsSubstituteMIR() for CMIR cuts
825- fixed several relaxations of the rhs of cuts to 0 in cuts.c
826- avoid aggregation into a single linear constraint if they should not be upgraded (needed for indicator constraints)
827- apply effective root changes before fork is repropagated during treeSwitchPath() in tree.c
828- avoid invalid objective value for solutions generated from an unbounded LP relaxation in case of a nonlinear objective function
829- disable recomputing symmetries after a restart (constraint removal is not permitted)
830- avoid cutting off optimal solutions for small feasibility tolerances in conflict analysis
831- initialize variable in presol_dualsparsify.c
832- fix in presolving of variable bound constraints to use absolute instead of relative difference
833- free variable histories in reoptimization mode
834- handle whitespaces in interactive shell history consistently
835- check and enforce equalities on which the objective is projected in cons_linear.c
836- ensure row feasibilities of solution shiftings in heur_oneopt.c and heur_twoopt.c
923- new parameters to turn on more statistics: misc/showdivingstats (diving heuristics), heuristics/alns/shownbstats (ALNS), estimation/showstats (tree size estimation)
924
925### Data structures
926
927- added nrootcalls and ncutsadded to SCIP_Cutpool
928- added fromcutpool flag to SCIP_Row and fixed 33 bit allocation
1079 Removed support for parameterized expressions.
1080- Added support for expression types sin, cos, and entropy. Added an expression type that stores a SCIP variable.
1081- Added handling of sin and cos expressions in OSiL reader.
1082- Added handling of sin, cos, and tan expressions in ZIMPL reader.
1083- Added expression handler plugin type, removed user expression type.
1084- Replaced expressions, expression trees, and expression graphs by a new implementation of expressions.
1085- Added differentiation methods (Gradients and Hessian directions) to expressions.
1086- Added integrality information to expressions.
1087- Added comparison and hashing of expressions.
1088- Improved simplification of expressions and identification of common subexpressions, in particular terms that appear
1089 equally in several quadratic functions are now identified.
1090- Expression simplification now expands powers also when the resulting exponents will be larger than 2.
1091- Added table to print statistics on expression handlers.
1092- Removed interval-arithmetic evaluation from expression interpreter (interfaces to automatic differentiation codes).
1093- Hessians for user-provided expression handlers are not available in the NLP solver interfaces for now.
1094- Sparse Hessians are now returned by expression interpreter. Removed dense Hessians.
1095
1096Constraint handlers for NLP:
1097- cons_nonlinear has been completely rewritten and now handles constraints of the form lhs <= expr <= rhs, where
1098 expr is an expression using the new expression type. A linear part of a nonlinear constraint is no longer distinguished.
1099- Methods that work on a particular nonlinear structure are now implemented via nonlinear handlers (nlhdlr).
1100 These handlers are plugins of cons_nonlinear and interact with cons_nonlinear by detecting structures in expressions and
1101 providing propagation and separation mechanisms.
1102- Added nlhdlr "default" as a mandatory nlhdlr: this is a nlhdlr that gets active on expressions that no other nlhdlr handles.
1103 It then uses the callbacks implemented in expression handlers to provide domain propagation and linear under/overestimates.
1104- Added nlhdlr for quadratic expressions: domain propagation that was previously part of cons_quadratic; separation via intersection cuts (currently disabled).
1105- Added nlhdlr for bilinear expressions: collects bilinear products and provides under/overestimation of a product over a 2D-projection of the LP.
1106- Added nlhdlr for convex and concave expressions: detection of convex/concave subexpressions and linear under/overestimation.
1107- Added nlhdlr for quotients: detects quotients, provides specialized linear under/overestimation and domain propagation for univariate quotients.
1108- Added nlhdlr for perspective reformulations: detects expressions in semi-continuous variables and tightens linear
1109 under/overestimates of these expressions by applying a perspective transformation.
1110- Added nlhdlr for second-order cones: detects second-order cone constraints (as ||x|| <= t or a quadratic that can written like that) and
1111 separates on a disaggregated reformulation (similar to cons_soc previously).
1112- Removed constraint handlers abspower, bivariate, quadratic, and soc.
1113- Removed simplification of duplicate abspower constraints for now.
1114 Removed simplification of abspower constraints with loose variables.
1115 Removed resolving of domain propagation (ConsResProp callback) and conflict analysis for abspower constraints.
1116 Removed propagation of varbounds for variables of abspower constraints.
1117 Removed reformulation of abs(x)^p * x into signpower expression for now.
1118- Removed reformulation of SOC constraints when adding to the NLP.
1119 Removed possibility to add linearizations a la Glineur or BenTal&Nemirovski for SOC constraints.
1120- Removed possibility to disaggregate quadratic constraints.
1121 Removed lifted tangent inequalities for bilinear terms in quadratic constraints.
1122 Removed option to project LP solution onto feasible region of a quadratic constraint via interior point or gauge function.
1123 Removed handling of unbounded LPs when enforcing quadratic constraints.
1124- Removed construction of cuts from interval gradients for nonlinear constraints.
1125 Removed possibility to pretend that all nonlinear constraints are convex.
1126 Removed possibility to create local or non-initial nonlinear constraints for now.
1127- Removed explicit reformulation of nonlinear constraints in presolve.
1128 An extended formulation is now generated implicitly and used to construct the LP relaxation,
1129 but the original formulation is used to check feasibility, propagate variable domains, etc.
1130 Variables that are added for the extended formulation are now marked as relaxation-only.
1131- Improved locking of nonlinear variables in nonlinear constraints by taking monotonicity into account.
1132- Improved mechanisms to detect and handle structures in nonlinear constraints, which allows for several algorithms
1133 to work simultaneously on equal or overlapping expressions.
1134- Improved linearization of (sums of) products of binary variables, e.g., clique information is now taken into account.
1135 Removed option to linearize products between a binary and a non-binary variable.
1136- Nonlinear constraints with the same function (but possibly different left- or right-hand-side) are now merged.
1137- 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.
1138- New branching rule for variables in nonlinear constraints (implemented in cons_nonlinear) that scores candidates
1139 based on constraint violation, variable type, and pseudo-costs simultaneously.
1140- Added tables to print statistics of nonlinear constraint handler and nonlinear handlers.
1141
1142Performance improvements
1143------------------------
1144
1145- Use the objective cutoff row as base row for separation in sepa_aggregation.c.
1146- Separate lifted cover cuts based on newer lifting function of Letchford and Souli (2019) in sepa_aggregation.c.
1147- In-tree restarts due to tree size estimation have been made compatible with orbital fixing.
1148- Improved upgrade of orbisacks to packing/partitioning orbitopes.
1149- Improved running time of symresack cover separation.
1150- Improved propagation algorithm for orbisack and symresack.
1151- Improved handling for expressions of type signpower in CppAD interface by making use of CppADs conditional expressions.
1152- Faster reevaluation of Hessian for quadratic expressions in CppAD interface.
1153- Enabled optimization of taped expressions in the CppAD interface.
1154- Sparse Hessian evaluation for expressions with sparse Hessian in the CppAD interface.
1155- Disabled branching on variables that are added for the extended formulation of a nonlinear constraint.
1156- 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.
1157- 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.
1158- Improved under/overestimation of multidimensional vertex-polyhedral (e.g., multilinear or concave) functions by use of scaling and keeping the cut-generating LP around.
1159- Products in nonlinear constraints are no longer disaggregated for the extended formulation.
1160- No longer relax bounds of integral variables when computing bounds on activity in nonlinear constraints.
1161- Revised and improved Ipopt interface.
1162- Revised and improved subNLP primal heuristic, in particular choice of iteration limit and starting condition and reuse of subSCIP.
1163- Merge strongcg into the gomory separator to avoid computing the same base equality twice. The files
1164 sepa_strongcg.{h|c} have been removed.
1165- The RENS neighborhood in ALNS now fixes fractional variables if necessary for reaching its target fixing rate.
1166- Use cpsolver emphasis in sepa_rapidlearning.
1167- If decomposition/maxgraphedge = 0, the computation of the block graph is completely turned off.
1168- Fixed a performance bug in cons_integral.c where rounding information was passed incorrectly to the generic diving algorithm.
1169
1170Examples and applications
1171-------------------------
1172
1173- Add c++ Sudoku example
1174- Removed circle.c and renamed string.c to spring.c in CallableLibrary example.
1175- SCIP-Jack (Steiner tree application):
1176 Most files have been modified and many new ones have been added (code base more than doubled).
1177 Two new problem classes are supported: maximum-weight connected subgraph problem with budget constraints, partial-terminal node-weighted Steiner tree problem.
1178 Major performance improvements accross all problem classes that are supported.
1179
1180Interface changes
1181-----------------
1182
1183### New and changed callbacks
1184
1185- extend SEPAEXEC{LP,SOL} callbacks by parameter "depth", which should be used within separation instead of SCIPgetCurrentDepth()
1186- extend SCIPseparateSolCutpool() by parameter "pretendroot", which is passed to SCIPcutpoolSeparate() instead of SCIPtreeGetCurrentDepth(scip->tree) == 0
1204- added SCIP_NLPIPROBLEM* problem to SCIP_DECL_NLPIGETSOLVERPOINTER
1205
1206### Deleted and changed API methods
1207
1208- When calling SCIPdelVar() in the SCIP_STAGE_PROBLEM stage, it is now documented as the user's responsibility to ensure
1209 the variable is not present in any constraints. Otherwise, SCIPsolve() now returns SCIP_INVALIDDATA.
1210- removed SCIPselectCuts(), replaced by SCIPselectCutsHybrid() of the hybrid cut selector plugin
1211- If SCIPvarMarkRelaxationOnly() is called for a variable, then this now need to happen before the
1212 variable is added to the transformed problem (SCIPaddVar()).
1213 SCIPvarMarkRelaxationOnly() will automatically call SCIPvarMarkDeletable().
1214- SCIPcomputeOrbitsFilterSym() and SCIPcomputeComponentsSym(): Type of argument componentblocked
1215 changed from SCIP_Shortbool* to unsigned*.
1216- removed SCIPsetParam()
1217- SCIPcreateConsOrbitope() and SCIPcreateConsBasicOrbitope() have two new arguments "usedynamicprop"
1218 and "mayinteract" to encode whether a dynamic reordering of the orbitope rows shall be used in
1219 full orbitope propagation and whether the orbitope might interact with other symmetry handling
1220 methods, respectively.
1221- internal function SCIPgetPropertiesPerm() has been replaced by SCIPisInvolutionPerm()
1222- internal function SCIPgenerateOrbitopeVarsMatrix() has new arguments "storelexorder", "lexorder",
1223 "nvarsorder", "maxnvarsorder" to compute and store the lexicographic order defined by an orbitope
1224- renamed SCIPcomputeArraysIntersection() and SCIPcomputeArraysSetminus() to
1225 SCIPcomputeArraysIntersectionInt() and SCIPcomputeArraysSetminusInt(), respectively, and changed
1226 their return type from SCIP_RETCODE (which _always_ was SCIP_OKAY) to void
1227- removed SCIPincludeDialogDefault(), use SCIPincludeDialogDefaultBasic() instead and check whether you also need SCIPincludeDialogDefaultSet() and SCIPincludeDialogDefaultFix()
1228- removed exprint argument from SCIPaddNlRowGradientBenderscutOpt()
1229- added copyexprhdlrs argument to SCIPcopyPlugins() (19th position)
1230- added copycutselectors argument to SCIPcopyPlugins() (10th position)
1231- removed refpoint argument from SCIPaddSquareSecant()
1232- added argument exprdata to SYMcomputeSymmetryGenerators()
1247- renamed SCIPsetNlRowExprtree() to SCIPsetNlRowExpr() and changed type of expr(tree) argument to SCIP_EXPR*
1248- SCIPenableNLP() is no longer allowed in stages INITSOLVE and SOLVING
1249- removed SCIPaddLinearConsToNlpHeurSubNlp()
1250- 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
1251- renamed SCIPsolveNLP() to SCIPsolveNLPParam() and added parameter SCIP_NLPPARAM param
1252- removed SCIPsolveDiveNLP(), use SCIPsolveNLPParam() instead
1300- removed SCIPnlpiOracleGetVarDegree() and SCIPnlpiOracleGetVarDegrees(), use SCIPnlpiOracleIsVarNonlinear() and SCIPnlpiOracleGetVarCounts(), respectively, instead
1301- removed SCIPnlpiOracleGetConstraintDegree(), use SCIPnlpiOracleIsConstraintNonlinear() instead
1302- removed argument messagehdlr from SCIPnlpiOraclePrintProblem() and SCIPnlpiOraclePrintProblemGams()
1303- removed SCIPcreateNlpiProb(), use SCIPcreateNlpiProblemFromNlRows() instead
1304- renamed SCIPupdateNlpiProb() to SCIPupdateNlpiProblem() and moved into scip_nlpi.{h,c}
1305- renamed SCIPaddNlpiProbRows() to SCIPaddNlpiProblemRows() and moved into scip_nlpi.{h,c}
1307- removed SCIPgetIpoptApplicationPointerIpopt(), use SCIPgetNlpiSolverPointer() instead
1308- removed SCIPnlpStatisticsCreate(), SCIPnlpStatisticsFree(), SCIPnlpStatisticsGetNIterations(), SCIPnlpStatisticsGetTotalTime(), SCIPnlpStatisticsSetNIterations(), SCIPnlpStatisticsSetTotalTime(), the struct is public now
1309- renamed LapackDsyev() to SCIPcallLapackDsyevIpopt()
1310- renamed SCIPsolveLinearProb() to SCIPsolveLinearEquationsIpopt()
1311
1312Expression interpreter:
1313- removed functions that operated with SCIPInterval
1314- changed first argument of SCIPexprintCreate() to SCIP*
1315- added SCIP* as first argument to SCIPexprintFree()
1316- added SCIP* as first argument to SCIPexprintCompile(), changed third argument to SCIP_EXPR*, added fourth argument SCIP_EXPRINTDATA**
1317- added arguments SCIP*, SCIP_EXPRINT*, and SCIP_EXPR* as first arguments to SCIPexprintFreeData()
1318- renamed SCIPexprintGetExprtreeCapability() to SCIPexprintGetExprCapability();
1319 added SCIP* as first argument, changed third argument to SCIP_EXPR*, added fourth argument SCIP_EXPRINTDATA*
1320- removed SCIPexprintNewParametrization()
1321- SCIPexprintEval(): added SCIP* as first argument, changed third argument to SCIP_EXPR*, added fourth argument SCIP_EXPRINTDATA*
1322- removed SCIPexprintEvalInt()
1323- SCIPexprintGrad(): added SCIP* as first argument, changed third argument to SCIP_EXPR*, added fourth argument SCIP_EXPRINTDATA*
1324- removed SCIPexprintGradInt()
1325- removed SCIPexprintHessianSparsityDense() and SCIPexprintHessianDense, use SCIPexprintHessianSparsity() and SCIPexprintHessian() instead
1326
1327Expressions:
1328- removed SCIPexpropGetName(), use SCIPexprhdlrGetName() instead
1329- removed SCIPexpropGetNChildren()
1330- removed SCIPexprGetOperator(), use SCIPexprGetHdlr() instead
1331- removed SCIPexprGetOpIndex(), SCIPexprGetOpReal(), SCIPexprGetOpData(), use SCIPexprGetData() instead
1332- removed SCIPexprGetRealPowerExponent(), SCIPexprGetIntPowerExponent(), SCIPexprGetSignPowerExponent(), use SCIPgetExponentExprPow() instead
1333- removed SCIPexprGetLinearCoefs(), SCIPexprGetLinearConstant(), use SCIPgetCoefsExprSum() and SCIPgetConstantExprSum() instead
1453- renamed SCIPgetNAllBilinearTermsQuadratic() to SCIPgetNBilinTermsNonlinear() and changed argument from SCIP* to SCIP_CONSHDLR*
1454- renamed SCIPgetAllBilinearTermsQuadratic() to SCIPgetBilinTermsNonlinear() and replaced arguments by SCIP_CONSHDLR* and changed return type to SCIP_CONSNONLINEAR_BILINTERM*
1455- removed SCIPaddBilinearIneqQuadratic(), use SCIPinsertBilinearTermImplicitNonlinear() instead
1456- renamed SCIPcreateConsQuadratic() to SCIPcreateConsQuadraticNonlinear() and removed argument stickingatnode
1457- removed SCIPincludeConshdlrSOC()
1458- replaced SCIPcreateConsBasicSOC() by SCIPcreateConsBasicSOCNonlinear()
1459- deprecated SCIPcreateConsSOC(), use SCIPcreateConsBasicSOCNonlinear() instead
1460- deprecated SCIPgetNlRowSOC(), use SCIPgetNlRowNonlinear() instead
1680- Removed parameters for strongcg separator: separating/strongcg/..., i.e.,
1681 maxrounds, maxroundsroot, maxsepacutsroot, maxsepacuts, dynamiccuts. One can control the
1682 strongcg behavior throught the parameters of sepa_gomory.
1683- renamed separating/{minortho,minorthoroot,objparalfac,intsupportfac} to cutselection/hybrid/{minortho,minorthoroot,objparalweight,intsupportweight}
1684
1685### New parameters
1686
1687- It is now possible to add orbitope constraints to handle symmetries even if not all variables
1688 in a component of the symmetry group are binary. This feature can be enabled using the
1747- new parameters "branching/inference/conflictprio" and "branching/inference/cutoffprio" that allow
1748 using the different score criteria in inference branching hierarchically
1749- new parameters "heuristics/alns/nodesquotmin", "heuristics/alns/maxcallssamesol" and "heuristics/alns/initduringroot"
1750 to control neighborhoods in ALNS
1751- new parameter "benders/default/benderscut/optimality/mir" to control whether mixed-integer rounding procedure is applied to Benders optimality cuts
1752- new parameter "misc/avoidmemout" to try to avoid running into memory limit
1868- added test projection:transitivity in prob/obbt.c
1869- added reader/nl.c
1870- added test intervalarith:sincos in scip/intervalarith.c
1871- added sepa/minor.c
1872- added sepa/rlt/cuts.c
1873- added sepa/rlt/product_detection.c
1874- added sepa/rlt/separation.c
1875- added tests test_compute_symmetry:expr{1,2,3,4} in symmetry/compute.c
1876
1877Build system
1878------------
1879
1880- the separate NLPI library has been integrated into the main SCIP library;
1881 uses of NLPILIBFILE or NLPILIBSRC in Makefiles that use make/make.project
1882 should be removed
1883
1884### Cmake
1885
1886- replace flag PARASCIP by THREADSAFE
1887- option AMPL is now ON by default
1888- add -D_XOPEN_SOURCE=600 cflag for compilation on systems other than windows
1889- add compile options directly instead of modifying CMAKE_C_FLAGS and CMAKE_CXX_FLAGS
1890
1891### Makefile
1892
1893- prefix PKG_CONFIG_PATH with Ipopt's pkgconfig dir instead of postfixing
1894- replace flag PARASCIP by THREADSAFE
1895- flag AMPL is now true by default
1896- libscip has been renamed to libscipbase and libscipsolver has been renamed to libscip
1897 in order to have the same library names for makefiles and cmake. For downward
1898 compatibility libscipsolver still exists (as a link).
1899
1900Fixed bugs
1901----------
1902
1903- fixed handling of multi-aggregation in cons_symresack and cons_orbisack
1904- SCIPgetLowerbound() now consistently returns infinity when status is infeasible
1905- improved the likelihood that a solution that satisfies the nonlinear constraints in the transformed (presolved) problem is also feasible for the original problem
1906- worked around a problem with derivatives of pow at 0 with non-integer exponents in CppAD
1907- fixed that setting of feasiblity and optimiality tolerance for NLP relaxation was overwritten with defaults when solving NLP
1908- fixed variance computation in t-value computation in hypothesis testing of reliability branching
1909- fixed potential overflow in cuts.c:evaluateLiftingFunctionKnapsack()
1910- do not transfer dual reductions to main SCIP in sepa_rapidlearning if strong dual reductions are forbidden
1911- fixed a bug in cons_setppc.c:removeDoubleAndSingletonsAndPerformDualpresolve() which led to wrong variable aggregations
1912- added missing redundancy check to coefficient tightening routine in cons_varbound that led to wrong variable locks
1913- added a check of numerics to avoid wrong reductions in cons_linear.c:simplifyInequalities()
1914- fixed a bug in cons_logicor.c regarding fixed variables that were not removed
1915- presol_milp.c handles variable fixings, suggested by PaPILO, more carefully to cover all cases that can appear
1916- fixed several reproducability bugs that led to different solving paths across multiple runs with one SCIP environment
1917- fixed check of limits/absgap, which was incorrectly applied to the scaled objective of the transformed problem
1918
1919Miscellaneous
1920-------------
1921
1922- in LP, use absolute instead of relative tolerances to check whether solutions from LP solver are primal feasible
1923- when a restart occurs, SCIP now asserts (during EXITSOLVE) that all relaxation-only variables are unlocked and
1924 only captured by the transformed problem.
1925- Avoid redundant calls to LP solver when LP is already flushed and solved
1926- In SCIPdebugMsg(), SCIPsetDebugMsg(), SCIPstatDebugMsg() strip directory from filename.
1927- Recompute activity of rows when checking LP solutions instead of trusting the value given by the LP solver
1928- The define NPARASCIP has been replaced by SCIP_THREADSAFE
1929- Parameters are not reset to their default values before activating an emphasis setting; this now allows to combine
1930 different emphasis settings.
1931- 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.
1932
1933@page RN7 Release notes for SCIP 7
1934
1935@section RN703 SCIP 7.0.3
1936*************************
1937
1938Interface changes
1939-----------------
1940
1941### New API functions
1942
1943- added function SCIPwithDebugSol() to determine whether SCIP was compiled with WITH_DEBUG_SOLUTION
1944
1945- New function SCIPcreateConsBounddisjunctionRedundant() and SCIPcreateConsBasicBounddisjunctionRedundant() that allow
1946 the input to contain redundant literals.
1947
1948### Changed API functions
1949
1950- added __attribute__((format(printf,,,))) to variadic SCIP message printing functions;
1951 this enables warnings about mismatches between format string and variadic function arguments if using GCC.
1952
1953### Interfaces to external software
1954
1955- removed MATLAB interface from interfaces/matlab
1956
1957Build system
1958------------
1959
1960- Compilation will now also work in a raw tarball of the scip git repository
1961
1962### Cmake
1963
1964- Make find_package more verbose and require packages to be found. Now enabled packages that are not found result in an error.
1965
1966Fixed bugs
1967----------
1968
1969- Fixed numerical bug by creating and checking the empty solution when problem vanishes in presolving.
1970- Fixed several bugs in reoptimization.
1971- Fixed bug in cons_bounddisjunction in which a constraint leads to a cutoff.
1972- Fixed bug in reoptimization by avoiding redundant literals for bound disjunctions.
1973- Replace wrong usage of CMAKE_BINARY_DIR by PROJECT_BINARY_DIR in CMake system
1974- Fixed lpi_glop to use absl flag instead of GFlags
1975- Fixed invalid initialization of limits/softtime parameter in cons_components
1976- Fixed MIN macro not defined in some cases.
1977- Safeguard some API methods for querying solving statistics against segmentation faults after SCIPpresolve()
1978- Fixed unfreed solution in concurrent solving
1979- Make sure that logicor constraints are enforced/separated if genlogicor is true in cons_indicator.
1980 Thus, do not change constraints/logicor/sepafreq anymore, but output warning.
1981- Fixed assert that assumed infeasibility cannot occur in presol_boundshift.
1982- Fixed sign bug during creation of conflict constraints with almost zero left-hand side.
1983- Disabled call of conflict handler for conflict sets that contain relaxation-only variables.
1984- Fixed bug in cons_symresack by initializing all constraint data in constrans
1985- Avoid allowing the upgrade of linear constraints corresponding to indicators in propagation of nodes.
1986- Fixed bug in computing lex. min/max faces in dynamic orbitope propagation.
1987- Limit vbounds propagator to one sweep through all bounds per call in order to avoid an infinite loop.
1988- Fixed mismatches between formatter strings and arguments in calls to SCIP message printing functions.
1989
1990Miscellaneous
1991-------------
1992
1993- To avoid performance variablity during reoptimization, the active constraints are now stored in the same order as in the
1994 original problem.
1995- Added workaround for bug in MSVS 2019 when compiling CppAD source.
1996- The original order of variables is now only restored after presolve if `randomization/permutevars` is set to FALSE.
1997
1998@section RN702 SCIP 7.0.2
1999*************************
2000
2001Features
2002--------
2003
2004- Extended check for valid variable and constraint names in PIP writer.
2005- Indicator constraints now write the name of the linear constraint in CIP format. This avoids a complicated
2006 name matching during parsing. The old format is still supported.
2007- The objective scale and offset are now taken into account when reading/writing problems in lp/mps/fzn/pip format.
2008 This often changes the behavior when writing transformed problems.
2009
2010Performance improvements
2011------------------------
2012
2013Examples and applications
2014-------------------------
2015
2016- Add c++ Sudoku example
2017
2018Interface changes
2019-----------------
2020
2021### Deleted and changed API methods
2022
2023- deprecated SCIPsetParam(); use SCIPsetIntParam(), SCIPsetRealParam(), etc, instead
2024
2025### New API functions
2026
2027- new function SCIPcolGetVarProbindex() for accessing the probindex of a variable corresponding to a column
2028- added new sorting functions SCIPsortPtrRealRealBoolBool()
2029
2030Fixed bugs
2031----------
2032
2033- Fixed a sign bug occuring for some cases in the computation of the directed cutoff distance
2034- Fixed overflow in inference information of cumulative constraint handler
2035- Fixed problem with propfreq == 0 in cons_linear.c
2036- Fixed aggregation heuristic in sepa_aggregation.c to not use local rows when that is requested nor modifiable rows
2037- Fixed problem with incompatibility of symmetry handling in Benders decomposition
2038- Fixed parsing of small number in CIP format of nonlinear constraint
2039- Fixed problem in upgrading full orbitopes to partitioning orbitopes
2040- Fixed treatment of negated variables in parsing orbitope constraints
2041- Fixed potential indexing error in prop_vbounds.c
2042- Fixed bug in writing fzn format
2043- Revert to old parameter value when parameter change is rejected in PARAMCHGD callback
2044- Fixed order of linker flags when building AMPL interface with cmake system.
2045- Fixed bug with ofsymcomptiming == 0: now symmetry is actually computed
2046- Improved separation for SOC constraint with multiaggregated variable on right-hand-side.
2047- Fixed bug in presol_boundshift: do not shift non-active variables
2048- Fixed bug in domain propagation for SOC constraints with negative coefficient for variable on right-hand-side.
2049- Fixed bug with multi-aggregated integer variables in cons_xor.
2050- Fixed bug with changed number of variables in storing relaxation solution in probing/diving.
2051- Fixed issues with scip statistics
2052- Fixed issue with multi-aggregated variables
2053- Fixed issue in with buffer memory in cons_cumulative
2054
2055@section RN701 SCIP 7.0.1
2056*************************
2057
2058Build system
2059------------
2060
2061### Cmake
2062
2063- Fixed cmake module for Ipopt to support Ipopt 3.13
2064- Added cmake variable BLISS_LIBRARY_DIR to pass a bliss library
2065- Added warning to require minimal GCC version 4.8
2066- Renamed FindCriterion cmake findmodule to FindCRITERION
2067
2068### Makefile
2069
2070- Updated make/make.project for macOS
2071- Add SANITZERFLAGS (only OPT=dbg) to LDFLAGS also if SHARED=true (and rename SANITZERFLAGS to SANITIZERFLAGS)
2072- Fixed GCC version check in make/make.linux.gnu.dbg
2073
2074Fixed bugs
2075----------
2076
2077- Fixed handling of constant term in quadratic objective of pip-reader
2078- Fixed incorrect value string for parameter estimation/completiontype
2079- Fixed initialization of first LP which led to wrong output about LPs not resolved correctly
2080- Fixed bug in SCIPcutpoolClear() function not clearing internal datastructures properly
2081- Fixed inability to set a value in a solution if it was within epsilon to the current value
2082- Fixed problems for linking optimized code with debug library of SCIP (and vice versa) by moving debug-only members
2083 to end of SCIP structs
2084
2085Miscellaneous
2086-------------
2087
2088- Variables that are marked as relaxation-only are no longer checked against debug solutions if
2089 they are captured by the transformed problem only.
2090
2091@section RN700 SCIP 7.0.0
2092*************************
2093
2094Features
2095--------
2096
2097- Using the parameter "propagating/symmetry/recomputerestart" one can now decide to recompute symmetries after a
2098 restart or not. Previously one could just turn off symmetry computation after a restart. If orbital fixing
2099 has found a reduction before the restart occured, symmetries have to be updated to ensure correctness.
2100 To this end, the user can decide via "propagating/symmetry/disableofrestart" whether orbital fixing is disabled or
2101 whether symmetries are recomputed.
2102
2103- extended relaxators statistics in solve statistics about information on number of cutoffs, improved bounds, etc.
2104
2105- extends SMPS file reader for the stochastic information, the sto files, to read a lower bound for the discrete
2106 scenarios. The lower bound is used when creating the auxiliary variables for Benders' decomposition.
2107
2108- extended Benders framework to solve NLPs and generate optimality and feasibility cuts from their solution
2109 when the subproblem is convex nonlinear.
2110
2111- extended Benders framework to create copies of Benders decompositions that can be used in a multithreading environment
2112
2113- additional functionality has been added to enable the transfer of Benders' decomposition cuts between different SCIP
2114 instances, e.g., when used in UG
2115
2116- LP rows (SCIP_ROW) can now store pointer to a constraint from which the row originates
2117
2118- Trust region, a new LNS heuristic, has been added to SCIP as both a standalone primal heuristic heur_trustregion.c
2119 and as a neighborhood inside of Adaptive Large Neighborhood Search (heur_alns.c). This heuristic is designed to improve the
2120 heuristic performance of the Benders' decomposition algorithm. It builds upon the successful trust region approaches
2121 applied to Benders' decomposition.
2122
2123- Modularity of symmetry handling has been increased. It is now possible to use orbitopes (i.e., polyhedral symmetry
2124 handling techniques) and orbital fixing on the same instance.
2125
2126- cut strengthening enabled within the Benders' decomposition framework. This uses a mix of the Improved Magnanti-Wong
2127 method and Kelly's method. The cut strengthening is enabled by setting the paramemter
2128 "benders/<bendersname>/cutstrengthenenabled" to TRUE. The parameters "cutstrengthenmult", "noimprovelimit" and
2129 "corepointperturb" control the behavior of the cut strengthening method. Additionally, the parameter
2130 "cutstrengthenintpoint" allows the user to specify the solution that is used to initialize the core point. The options
2131 are the first LP solution, the first integer feasible solution, a relative interior point, a solution vector of all
2132 ones and a solution vector of all zeros. Also, the core point can be reinitialized after each update to the incumbent
2133 solution.
2134
2135- added option to adjust weights of different scores in relpscost (hybrid) branching rule based on degeneracy information
2136 and skip strong branching for very high degeneracy rates
2137
2138- added new SCIP_DECOMP* object to store user decompositions. The user can specify one or several decompositions by assigning variable
2139 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).
2140 This format specifies constraint labels, variable labels are inferred from that. The decomposition is transformed after presolving.
2141- statistics regarding the number of blocks, the largest and smallest blocks, the border, and the constraint graph are printed for the original decomposition,
2142 and for each decomposition after presolving.
2143- the decomposition can be used as initial decomposition for the Benders functionality of SCIP.
2144- new subsection "How to provide a problem decomposition" in the SCIP documentation
2145
2146- GINS heuristic can make use of a user-provided decomposition labels in two ways:
2147 1. by selecting a block of variables that maximizes the potential, and randomly selecting a start variable for the neighborhood and/or
2148 2. by selecting an interval of consecutive blocks as neighborhood, until fixing rate is reached. In this case, no variable is randomly selected.
2149
2150- extend potential parameter of GINS to allow computation based on local LP solution, as well
2151
2152- new primal heuristic Adaptive Diving, which registers all publicly available dive sets from other diving heuristics.
2153 At each call, it selects one of the available dive sets based on the user's score type choice (heuristics/adaptivediving/scoretype).
2154 During the solution process, the heuristics learns online which divesets reach the best score, and executes them more frequently.
2155 The statistic output for Diving heuristics has been extended to incorporate the statistics of each dive set within Adaptive diving.
2156
2157- Added new penalty alternating direction method (PADM) primal heuristic that splits the problem into several sub-SCIPs
2158 according to a user-provided decomposition. The sub-SCIPs are solved on an alternating basis until a feasible solution of
2159 the original problem is found.
2160
2161- Symmetry handling constraints (cons_orbisack, cons_orbitope, cons_symresack) now have an additional parameter to encode
2162 whether they are model constraints, i.e., define the problem, or whether they are only present to handle symmetries.
2163
2164- The symmetry code has been completely restructured. The presolvers presol_symbreak and presol_symmetry as well as the propagator
2165 prop_orbitalfixing have been merged into the single propagator prop_symmetry to avoid storing the same information
2166 multiple times. This propagator is now responsible for adding symmetry handling constraints as well as activating orbital
2167 fixing. Moreover, the new file symmetry.c contains general functions for symmetry computations like orbit computations.
2168
2169- Variables can now be marked as "relaxation-only". This flag should be used to introduce new variables that are required
2170 to define a relaxation, but that are not part of any checked constraints. Essentially, these variables should only be used
2171 in the current SCIP solve and disregarded after a restart or in SCIP copies. Hence, these variables are not copied by SCIPcopy and
2172 SCIPgetVarCopy, they are currently not used in conflict constraints, and cuts involving them are not upgraded to linear constraints.
2173 Relaxation-only variables cannot appear in the objective function.
2174
2175- The OSiL reader now supports nonlinear expressions of type "signpower".
2176
2177- Expressions of form abs(x)^p * x in a nonlinear constraint are now sometimes recognized and handled by abspower constraints.
2178
2179- If polyhedral symmetry handling methods are used (cons_orbisack, cons_orbitope, cons_symresack), it is now possible to
2180 recompute symmetries if a restart occured.
2181
2182- upgrade some more quadratic constraints to second-order cone constraints, that is,
2183 handle linear binary variables as if squared in simple upgrade and
2184 do not require bounds for variables that have a zero entry in the computed eigenvectors in the non-simple upgrade
2185
2186- new variable event when changing the variable type
2187
2188- It is no longer necessary to provide a SCIP pointer for the subproblem in SCIPaddBendersSubproblem if custom solving
2189 methods are defined. A NULL pointer can be supplied to SCIPaddBendersSubproblem. In this case, no internal Benders'
2190 cut generation methods can be used.
2191
2192- Using the parameter "constraints/symresack/checkmonotonicity" one can now decide to upgrade to packing/partitioning
2193 symresacks even if the underlying permutation is not monotone.
2194
2195- New branching rule `vanillafullstrong`, mostly for scientific purpose, with the following features:
2196 1) no cutoff or domain reduction: only branching;
2197 2) idempotent (optional): leave SCIP, as much as possible, in the same state before / after the strong branching calls
2198 - basically, do not update any statistic;
2199 3) donotbranch (optional): do no perform branching. So that the brancher can be called as an oracle only
2200 (on which variable would you branch ? But do not branch please);
2201 4) scoreall (optional): keep scoring variables, even if infeasibility is detected;
2202 5) collectscores (optional): store the candidate scores from the last call, which can then be retrieved by calling SCIPgetVanillafullstrongData();
2203 6) integralcands (optional): consider integral candidates for branching,
2204 i.e., get candidates from SCIPgetPseudoBranchCands() instead of SCIPgetLPBranchCands().
2205
2206- If a reference value (misc/referencevalue) is given, the primal-reference and reference-dual integrals are calculated automatically and printed within the SCIP statistics.
2207
2208- Locally valid cuts / rows are now considered for dual proof analysis when `conflict/uselocalrows` is set to TRUE.
2209
2210- 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.
2211
2212- To save memory, it is now possible to remove all variables from the internal symmetry data structures that are
2213 not affected by any symmetry.
2214
2215- Allow to filter first variables from orbits and transfer pseudo cost information to variables in orbit
2216
2217- Add integration of external MILP presolve library as a SCIP presolver plugin that runs on MILP problems
2218
2219- Parallelisation can be used when applying Benders' decomposition. There are two different forms of parallelisation
2220 available. The first is applying Benders' decomposition within a parallel branch-and-bound. This is achieved through
2221 the integration with the UG framework. The second is the use of shared memory parallelisation for solving the Benders'
2222 decomposition subproblems. A priority queue has been added to help with load balancing.
2223
2224- The Benders' decomposition framework can handle MINLPs. If a convex relaxation of the MINLP exists, then this is
2225 solved to generate optimality and feasibility cuts. The extensions to the framework are:
2226 - New generic solving methods to solve convex NLP subproblems.
2227 - Modification to benderscut_opt and benderscut_feas to enable the generation of cuts from convex NLPs.
2228 - Addition of benderscut_feasalt to generate feasibility cuts from an alternative subproblem that minimises the
2229 violation of infeasible problems.
2230 - Better handling of subproblem solution results
2231
2232- Adds a feasibility phase to the Benders' decomposition subproblem solving methods. The feasibility phase adds slack
2233 variables to each of the constraints to ensure feasibility of the subproblem. A large coefficient is given to these
2234 slack variables in the objective function to penalise constraint violations. The coefficients are progressively
2235 increased until all slack variables take the value 0.0.
2236
2237- Improved convexity check for Benders' decomposition subproblems. The constraints of the subproblem are now checked for
2238 convexity in the initialisation of the Benders' decomposition algorithm. This enables the solving of convex NLPs as
2239 Benders' decomposition subproblems.
2240
2241- Benders' decomposition can be applied using decomposition supplied in the DEC format. To apply Benders' decomposition
2242 the parameters decomposition/benderslabels and decomposition/applybenders must be set to TRUE.
2243
2244- new event handler event_estim.c/h that approximates search tree completion and estimates tree size
2245 to trigger restarts; many approximations of search tree completion and estimation, including WBE, SSG, and tree profile method
2246- new display column that reports approx. search tree completion during the search, and an overview in the statistics table
2247- added resources (script, tutorial, test data) to adapt tree size estimation to user instances.
2248
2249- Orbital Fixing uses a list of variables that have been fixed globally since the computation of symmetries to filter
2250 symmetries. Previously, some plugins were disabled, which is not necessary anymore.
2251
2252- A new presolver "dualsparsify" was added. It tries to combine columns (i.e. variables) to cancel nonzero coefficients in the constraint matrix.
2253
2254- The presolver "tworowbnd" was implemented with better performance.
2255
2256- 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.
2257
2258- allow disabling of pricers during solving process
2259
2260- added emphasis setting for numerically challenging instances
2261
2262Performance improvements
2263------------------------
2264
2265- Extended cut presolving by removing variables that been fixed at their bounds
2266
2267- Improved branching point selection when branching on externals branching candidates. Instead of using exactly the
2268 LP solution, a point closer to the middle of the variables domain is chosen.
2269
2270- Matrix presolvers that do not work on incomplete matrices now skip matrix creation if unsupported constraint types are detected.
2271
2272- consLockBenders callback implemented to add down locks on the Benders' decomposition auxiliary variables and
2273 up and down locks per subproblem for all master problem variables. This allows the use of presolving and propagation
2274 with Benders' decomposition.
2275
2276- improved performance of orbital fixing in several ways:
2277 store permutations in transposed form to improve cache efficency;
2278 reverse order to speed up filtering of permutations;
2279 handle variables globally fixed to 1 in list;
2280 use event handler to catch global fixings;
2281 speed up orbit computations;
2282 change handling of restarts;
2283 use only permutations that can contribute to a variable's orbit;
2284
2285- allow rapid learning at local nodes
2286
2287- allow to recompute cut without using fractional values for sepa_cgmip
2288
2289- restrict the number of the clique table nonzeros relative to the number of problem nonzeros, which could be a performance bottleneck.
2290
2291- variable fixings of LP face heuristic are now computed earlier; subproblem creation is skipped if not enough variables are fixed.
2292
2293- Improved domcol presolver to not require a complete representation of all constraints in the matrix
2294
2295- performance improvement of adaptive large neighborhood search heuristic on merely continuous problems. The heuristic
2296 stops if presolving in the sub-SCIP fixes less than 50 % of the current target fixing rate over all variables
2297 (including continuous).
2298
2299- reduce memory usage in symmetry detection by a staggered allocation with decreasing overhead for larger instances
2300
2301- improved full orbitope propagation using a static implementation or a dynamic reordering of orbitope rows by a global rank function
2302
2303- improved detection of packing/partitioning orbitopes
2304
2305- enable an in-tree restart if after a reasonable initialization, the estimated size of the remaining tree is large.
2306
2307
2308Examples and applications
2309-------------------------
2310
2311- added methods to set and get hmin and hmax for optcumulative constraints
2312
2313Interface changes
2314-----------------
2315
2316### New and changed callbacks
2317
2318- new optional callback `SCIP_DECL_DIVESETAVAILABLE` to check preconditions for this dive set, e.g., if an incumbent solution is available,
2319 which is passed as new argument to SCIPcreateDiveset(). SCIPcreateDiveset() has another new parameter "ispublic".
2320
2321- new callback `SCIP_DECL_CONSHDLRCOPY` and `SCIP_DECL_CONSCOPY` in cons_orbisack and cons_symresack
2322
2323- new `idempotent` argument to SCIPgetVarStrongbranchInt() and SCIPgetVarStrongbranchFrac(),
2324 so that statistics are not updated during the call. Likewise, new `updatecol` and `updatestat` arguments to SCIPcolGetStrongbranch().
2325
2326- callback `SCIP_DECL_CONSHDLRENFOLP` can now also return SCIP_SOLVELP as *result, which indicates to the SCIP core that the LP relaxation
2327 should be solved again because the primal feasibility tolerance of the LP has been tightened (using SCIPsetLPFeastol())
2328
2329- 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.
2330
2331### Deleted and changed API methods
2332
2333- LPI:
2334 + now for all lp interfaces consistent requirements on SCIP_LPPAR:
2335 LPITLIM and BARRIERCONVTOL positive or zero; FEASTOL, DUALFEASTOL, LPTILIM strictly positive
2336 + now projecting SCIP_LPPAR values on feasible values for each lp interface
2337 + add interface to Glop
2338 + fixed mapping between scaling parameter values in Gurobi LPI lpi_grb
2339- Symmetry:
2340 + removed method SCIPseparateCoversOrbisack() in cons_orbisack.h since the orbitope constraint
2341 handler has its own implementation of this routine with advanced features now
2342 + renamed SCIPgetGeneratorsSymmetry() to SCIPgetSymmetry() and removed two arguments
2343 + extended method SCIPgetSymmetry(): It is possible to access both the original and
2344 transposed permutations matrix as well as the (independent symmetry) components of a permutation group now.
2345 + arguments of functions SCIPcreateConsOrbisack(), SCIPcreateConsBasicOrbisack(), SCIPcreateConsOrbitope(),
2346 SCIPcreateConsBasicOrbitope(), SCIPcreateConsSymresack(), SCIPcreateConsBasicSymresack(), and SCIPcreateSymbreakCons() extended
2347 by "ismodelcons" to encode whether the constraints are model constraints or not
2348 + the function SCIPgetSymmetry() no longer accepts the parameter recompute, but has parameter permvarmap as new input
2352 + add function SCIPcomputeOrbitsComponentsSym() to compute orbits without filtering permutations and indices of orbits for each variable
2353- SCIPallowObjProp() and SCIPallowDualReds() are deprecated and replaced by SCIPallowWeakDualReds() and SCIPallowStrongDualReds(), respectively
2354- Benders' decomposition
2355 + changed SCIPstoreBenderscutCut() in scip_benders.c to SCIPstoreBendersCut(). Where this function used to take a
2356 SCIP_BENDERSCUT pointer, it now accepts a SCIP_BENDERS pointer.
2357 + the functions SCIPsolveBendersSubproblem() no longer accepts the parameter type. The type is not a necessary
2358 argument for the subproblem solving method.
2359 + arguments of functions SCIPbendersSolveSubproblemLP(), SCIPbendersSolveSubproblemCIP(), and SCIPbendersOnlyCheckConvexRelax() changed
2360 - removed SCIPbenderscutGetNAddedCuts() and SCIPbenderscutGetAddedCutData()
2361
2362
2363### New API functions
2364
2365- new argument "onlyifcomplete" in SCIPmatrixCreate() to skip matrix creation right after detecting unsupported constraint types
2366 and new arguments to count statistics when doing a clean-up of inactive variables in the constraints before building the matrix
2367
2368- new argument "threadsafe" in SCIPcopy(), SCIPcopyConsCompression(), SCIPcopyOrig(), SCIPcopyOrigConsCompression and
2369 SCIPcopyBenders(). This argument must only be set to TRUE if the source and target SCIP instances are to be solved in
2370 parallel. Setting this argument to TRUE has a performance cost.
2371
2372- new argument "append" in SCIPsetModifiedDefaultSettingsIpopt()
2373- functions SCIPclearRelaxSolVals(), SCIPsetRelaxSolVal(), SCIPsetRelaxSolVals(), SCIPsetRelaxSolValsSol(), and SCIPmarkRelaxSolValid()
2374 receive an additional argument "relax" to store the relaxation handler as creator of the relaxation solution.
2375
2376- LP:
2377 - SCIProwGetOriginCons() now returns a SCIP_CONS* instead of a SCIP_CONSHDLR*, use SCIProwGetOriginConshdlr() for the previous behavior
2378 - SCIPcreateRowCons() and SCIPcreateEmptyRowCons() now expect a SCIP_CONS* instead of a SCIP_CONSHDLR*,
2379 use SCIPcreateRowConshdlr() and SCIPcreateEmptyRowConshdlr(), respectively, for the previous behavior
2380 - deprecated SCIPlpfeastol() and SCIPchgLpfeastol(), use SCIPgetLPFeastol() and SCIPsetLPFeastol()
2381
2382- new parameter "divecontext" for every method that queries statistics for a diveset. The context can be used to distinguish between the dive set
2383 as single (standalone) heuristic or within Adaptive Diving.
2384- new parameters "divecontext" and "iterlim" to SCIPperformGenericDivingAlgorithm() to control in which context (single,adaptive) statistics are updated.
2385
2386- SCIPcopyVars, SCIPcopy, SCIPcopyConsCompression, and SCIPgetVarCopy do not copy variables that are marked as relaxation-only,
2387 thus it cannot be assumed anymore that each active variable from the master SCIP also has a counterpart in the copy.
2388 SCIPcopy, SCIPcopyConsCompression, and SCIPcopyConss can now return *valid=TRUE if some non-checked and non-enforced constraints were not copied, e.g.,
2389 because they involved relaxation-only variables. Thus, a copy is already regarded as valid if all checked or enforced constraints were copied successfully.
2390
2391- linking constraint handler:
2392 - changed type of vals argument from int* to SCIP_Real* in SCIPcreateConsLinking() and SCIPcreateConsBasicLinking()
2393 - SCIPgetIntvarLinking() has been renamed to SCIPgetLinkvarLinking().
2394 - changed return value of SCIPgetValsLinking() from int* to SCIP_Real*.
2395 - new method SCIPgetBinvarsDataLinking().
2396
2397- SCIPbendersCheckSubproblemOptimality() now returns a boolean indicating whether the subproblem is optimal or not.
2398 Previously this result was returned through a parameter. The change was required to facilitate the integration with
2399 the UG framework.
2400
2401- deleted SCIPcombineTwoInt(), SCIPcombineThreeInt(), SCIPcombineFourInt(); use the appropriate SCIPhashTwo(), ..., SCIPhashSeven() method instead
2402
2403- SCIPsetupBendersSubproblem takes a parameter of the enforcement type.
2404
2405- SCIPcreateNlpiProb takes a hashmap to store the map between the nlrows and the index in the nlrow array.
2406
2407### New API functions
2408
2409- SCIPallowWeakDualReds() and SCIPallowStrongDualReds() replace the deprecated SCIPallowObjProp() and SCIPallowDualReds(), respectively
2410- methods have been added to facilitate the transfer of Benders' decomposition cuts between solvers in UG. These include
2411 SCIPapplyBendersStoredCuts(), SCIPbendersGetNStoredCuts(), SCIPbendersGetStoredCutData() and
2412 SCIPbendersGetStoredCutOrigData().
2413- added SCIPisConvexAbspower()
2414- new functions SCIPsolGetType(), SCIPsolGetRelax(), SCIPsolSetRelax(), SCIPsolSetLPRelaxation(), SCIPsolSetStrongbranch(),
2415 SCIPsolSetPseudo to set or query the new type attribute of a primal solution. The type attribute gives information
2416 about the origin of the solution, ie, whether it was created by a relaxation handler,
2417 by the LP relaxation, by strong branching, by the current pseudo solution, or by a primal heuristic.
2418 The meaning of the argument 'heur' in all creation methods for primal solutions such as SCIPcreateSol() stays unchanged.
2420- new API functions SCIPsetCommonSubscipParams(), SCIPtranslateSubSol(), and SCIPtranslateSubSols() shared by several Large Neighborhood Search heuristics.
2421- new API function SCIPgetLPDualDegeneracy() to get two measures for the dual degeneracy of the current LP
2422- new API functions SCIPdivesetIsAvailable() to check preconditions of a dive set and SCIPdivesetIsPublic() to check if the dive set can be used
2423 by other primal heuristics.
2424- new API functions SCIPcomputeOrbitsSym(), SCIPcomputeOrbitsFilterSym(), SCIPgetPropertiesPerm(), SCIPdetermineBinvarAffectedSym(),
2425 SCIPdetermineNVarsAffectedSym(), SCIPcomputeComponentsSym(), and SCIPextendSubOrbitope(), SCIPgenerateOrbitopeVarsMatrix() for symmetry computations
2426- new API functions SCIPvarIsRelaxationOnly() and SCIPvarMarkRelaxationOnly() to query and set, resp., whether a variable is marked as relaxation-only
2427- new API functions SCIPconshdlrGetNUpdateConss() and SCIPconshdlrGetUpdateConss(), for expert users only
2428- new API function SCIPgetNConflictDualproofsApplied()
2429- new API functions SCIPeventGetOldtype() and SCIPeventGetNewtype() for the new event when changing the variable type
2430- new API function SCIPisConvexConsQuadratic() to check whether a quadratic constraint is convex when a given set of variables would be fixed
2431- new API functions SCIPgetLPFeastol(), SCIPsetLPFeastol(), and SCIPresetLPFeastol() to get, set, and reset (to the default), respectively, the primal
2432 feasibility tolerance for the LP relaxation
2433- new API functions SCIPcleanupConss{Linear,Varbound,Setppc,Logicor,Knapsack}() to clean up inactive variables from those types of linear constraints
2434- new API function SCIPsetBendersSubproblemComp() used to add a custom comparison method for ordering the Benders'
2435 decomposition subproblem solves. The comparison method is used to help with load balancing.
2436- new API function SCIPgetRowObjParallelism to get the objective parallelism of a row
2437- new API function SCIPcolGetAge to get the age of a column
2438- added SCIPhashThree(), SCIPhashFive(), SCIPhashSix(), and SCIPhashSeven() that complement SCIPhashTwo(), SCIPhashFour() to combine 32bit integers to
2439 a 32bit hash value
2440- new API function SCIPgenerateAndApplyBendersOptCut is used to generate a Benders' optimality cut using the dual
2441 solutions. This function can be supplied vectors for the primal and dual solution for generating an optimality cut.
2442 This avoids the need for a SCIP instance to solve the Benders' decomposition subproblem and generating cuts.
2443- new API function SCIPconsAddCoef used for adding a coefficient to a linear-type constraint.
2444- new API functions SCIPconsNonlinearGetRhs, SCIPconsNonlinearGetLhs and SCIPconsNonlinearAddLinearCoef for getting the
2445 RHS and LHS from a nonlinear-type constraint and adding a linear coefficient to the constraint.
2446- new API function SCIPbendersSolSlackVarsActive for checking whether any slack variables from the feasibility phase are
2447 active in the subproblem solution.
2448- new API functions SCIPbendersSetSubproblemType and SCIPbendersGetSubproblemType sets and gets the subproblem type.
2449 This is either:
2450 - Convex constraints with continuous variables
2451 - Convex constraints with discrete variables
2452 - Non-convex constraints with continuous variables
2453 - Non-convex constraints with discrete variables
2454- new API functions SCIPbendersSetSubproblemIsNonlinear() and SCIPbendersSubproblemIsNonlinear() for setting and
2455 identifying whether the Benders' decomposition subproblems contain nonlinear constraints. Similarly, the functions
2456 SCIPbendersSetMasterIsNonlinear() and SCIPbendersMasterIsNonlinear() sets and identifies whether the Benders'
2457 decomposition master problem contains nonlinear constraints.
2458- new API function SCIPapplyBendersDecomposition for applying Benders' decomposition given a decomposition in the DEC
2459 format
2460- new API function SCIPwasNodeLastBranchParent to query if a node has been the parent of the most recent branching in the tree
2461- new API functions SCIPtreemodelInit(), SCIPtreemodelFree(), SCIPtreemodelIsEnabled(), SCIPtreemodelSelectCandidate() related to the new
2462 treemodel way of comparing branching candidates. These functions are only currently used for reliability pscost branching, but they can be used
2463 in other parts of the code.
2464- New function SCIPcalcChildEstimateIncrease() to compute the increase in the child estimation
2465- new API functions SCIPisOrbitalfixingEnabled() and SCIPgetSymmetryNGenerators() to check whether orbital fixing is
2466 enabled and to get the number of generators of the current symmetry group, respectively
2467- new API function SCIPdelNlRow() to remove a row from the NLP
2468
2469### Event system
2470
2471- new event type SCIP_EVENTTYPE_NODEDELETE to react on nodes that are about to be deleted from the tree
2472
2473### Changed parameters
2474
2475- renamed parameter "propagating/orbitalfixing/enableafterrestart" to ".../symmetry/recomputerestart"
2476- Parameter "misc/allowdualreds" is now called "misc/allowstrongdualreds"
2477- Parameter "misc/allowobjprop" is now called "misc/allowweakdualreds"
2478- changed default values of propagation (new value: 1, old value: 5) and separation frequency (new value: -1, old value: 5) in cons_orbitope.c
2479- all primal heuristics that use sub-SCIPs are disabled within the heuristics fast emphasis setting
2480- deleted parameter heuristics/localbranching/useuct, use heuristics/useuctsubscip instead
2481- changed default value of "presolving/symbreak/detectorbitopes" (new value: TRUE, old value: FALSE)
2482- extended range of "misc/usesymmetry" (new range: [0,3], old range: [0,2])
2497- changed default value of "heuristics/coefdiving/freq" (old: 10, new: -1)
2498- changed default value of "heuristics/conflictdiving/freq" (old: -1, new: 10)
2499- changed default value of "heuristics/conflictdiving/lockweight" (old: 1.0, new: 0.75)
2500- replaced parameter "numerics/lpfeastol" by "numerics/lpfeastolfactor" to specify which factor should be applied to the SCIP feasibility
2501 tolerance to initialize the primal feasibility tolerance of the LP solver
2502- enabling aggressive presolving now activates all available presolving plugins,
2503 and decreases the presolving/restartfac parameter correctly with respect to default.
2504- changed default value of heuristics/rins/nodesquot to 0.3 (was 0.1), to compensate
2505 the removal of a hard coded factor of 3.0 in the code without affecting the default behavior
2506 of the RINS heuristic.
2507- changed default value of "constraints/quadratic/empathy4and" (old: 0, new: 2)
2508- changed default value of "propagating/redcost/useimplics" (old: TRUE, new: FALSE)
2509
2510### New parameters
2511
2512- the possibility to define the Benders' decomposition auxiliary variables as implicit integer is provided. This
2513 behavior is controlled with an additional parameter in the Benders' decomposition framework.
2514- added parameter benders/<bendersname>/cutcheck to enable the generation of Benders' decomposition cuts during solution
2515 checking.
2516- constraints/orbitope/usedynamicprop: the possibility to propagate orbitope constraints by reordering the rows based on the
2517 branching strategy is provided (only possible for non-model constraints)
2518
2519- new parameters heuristics/shiftandpropagate/minfixingratelp and heuristics/locks/minfixingratelp to stop the
2520 heuristics after propagating integer fixings if no sufficient fixing of the all variables (including continuous)
2521 could be achieved. These parameters help to avoid solving LP's that are comparable in hardness to the main root LP.
2522
2523- Added parameters branching/midpull and branching/midpullreldomtrig to control by how much to move
2524 the branching point for an external branching candidate closer to the middle of the candidates domain. The
2525 default of 0.75 and 0.5, respectively, uses a point that is 75*alpha% closer to the middle of the domain, where
2526 alpha is the relative width of the candidates domain (width of local domain divided by width of global domain),
2527 if the latter is below 0.5, and alpha=1.0 otherwise. That is, with the default settings, a branching point is
2528 chosen closer to the middle of the candidates domain if the variables local domain is still similar to its
2529 global domain, but is chosen closer to the LP solution if the local domain is much smaller than the global
2530 domain.
2531
2532- Added parameter lp/minmarkowitz to set the Markowitz stability threshold (range 0.0001 to 0.9999).
2533 High values sacrifice performance for stability.
2534
2535- Added parameters benders/<bendersname>/lnsmaxcalls and benders/<bendersname>/lnsmaxcallsroot to the Benders'
2536 decomposition core. These parameters limit the number of Benders' decomposition subproblem checks, for the full
2537 branch-and-bound tree and root node respective, when solving the auxiliary problem of LNS hueristics. These
2538 parameters only have effect if the lnscheck parameter is set to TRUE.
2539
2540- Added parameter cons/linear/maxmultaggrquot to limit the maximum coefficient dynamism of an equation on which
2541 multiaggregation is performed. This replaces a compiler define of the same name.
2542 Default value is 1000, smaller values make multiaggregations numerically more stable.
2543- new global parameter heuristics/useuctsubscip that affects all LNS heuristics using common sub-SCIP parameters
2544
2545- new parameter branching/relpscost/degeneracyaware to switch degeneracy-aware hybrid branching
2546
2547- new parameter separation/rapidlearning/checkexec to check whether rapid learning is allowed to run locally
2548- new parameters separation/rapidlearning/check{degeneracy,dualbound,leaves,nsols,obj} to enable checking the respective feature for local rapid learning
2549- new parameter separation/rapidlearning/maxcalls to limit the number of rapid learning executions
2550- new parameter separation/rapidlearning/nwaitingnodes to set the number of waiting nodes before the dual bound is checked
2551- new parameter separation/rapidlearning/mindegeneracy to set the minimal threshold of degenerate basic-variables
2552- new parameters separation/rapidlearning/minvarconsratio to set the minimal ratio of unfixed variables in relation to basis size
2553
2554- new parameters to control the Benders' decomposition two-phase method.
2555 - constraints/benderslp/depthfreq: after the maxdepth is reached, then the two-phase method will only be called at
2556 nodes at a depth divisible by depthfreq.
2557 - constraints/benderslp/stalllimit: after the maxdepth is reached, if there has been no improvement in the dual bound
2558 for stalllimit number of nodes, then the two-phase method is executed for the next fractional LP solution that is
2559 encountered.
2560 - constraints/benderslp/iterlimit: after the root node, only iterlimit fractional LP solutions are used at each node
2561 to generate Benders' decomposition cuts.
2562
2563- new parameters for symmetry handling
2564 - new parameter "propagating/symmetry/maxgenerators"
2565 - new parameter "propagating/symmetry/checksymmetries"
2566 - new parameter "propagating/symmetry/displaynorbitvars"
2567 - new parameter "propagating/symmetry/conssaddlp"
2568 - new parameter "propagating/symmetry/addsymresacks"
2569 - new parameter "propagating/symmetry/detectorbitopes"
2570 - new parameter "propagating/symmetry/addconsstiming"
2571 - new parameter "propagating/symmetry/ofsymcomptiming"
2572 - new parameter "propagating/symmetry/performpresolving"
2573 - new parameter "propagating/symmetry/recomputerestart"
2574 - new parameter "constraints/symresack/checkmonotonicity"
2575 - new parameter "propagating/symmetry/compresssymmetries"
2576 - new parameter "propagating/symmetry/compressthreshold"
2577 - new parameter "propagating/symmetry/disableofrestart"
2578 - new parameter "propagating/symmetry/symfixnonbinaryvars"
2579
2580- new parameter for enabling shared memory parallelisation for solving Benders' decomposition subproblems. The parameter
2581 benders/<bendersname>/numthreads sets the number of threads used for parallel subproblem solving.
2582
2583- new parameters to control enhancements for solving MINLPs by Benders' decomposition
2584 - benders/<bendersname>/execfeasphase: enables the feasibility phase for solving the Benders' decomposition
2585 subproblems
2586 - benders/<bendersname>/slackvarcoef: the initial coefficient of the slack variable for the feasibility phase
2587 - benders/<bendersname>/checkconsconvexity: should the constraints be checked for convexity. This can be set to FALSE
2588 if you are certain that the NLP subproblem is convex.
2589
2590- new parameter presolving/clqtablefac (default value 2.0) as limit on number of entries in clique table relative to number of problem nonzeros
2591
2592- new parameter conflict/uselocalrows (default: TRUE) to incorporate locally valid cuts / rows for dual proof analysis
2593
2594- new return code SCIP_NOTIMPLEMENTED for functions, e.g., in the LPI that have not been implemented (yet)
2595
2596- new parameter separating/cgmip/genprimalsols that allows to generate initial primal solutions from Gomory cuts
2597
2598- new parameter branching/relpscost/filtercandssym to allow filtering from orbits
2599
2600- new parameter branching/relpscost/transsympscost to transfer pseudo cost information to orbit
2601
2602- new parameters for tree size estimation and restarts:
2603 - estimation/restarts/restartpolicy (default value n)
2604 - estimation/method (default value c)
2605 - estimation/restarts/restartlimit (default value 1)
2606 - estimation/restarts/minnodes (default value 1000)
2607 - estimation/restarts/countonlyleaves (default value FALSE)
2608 - estimation/restarts/restartfactor (default value 2)
2609 - estimation/coefmonoprog (default value 0.3667)
2610 - estimation/coefmonossg (default value 0.6333)
2611 - estimation/restarts/hitcounterlim (default value 50)
2612 - estimation/reportfreq (default value -1)
2613 - estimation/regforestfilename (default value "-")
2614 - estimation/completiontype (default value a)
2615 - estimation/treeprofile/enabled (default value FALSE)
2616 - estimation/treeprofile/minnodesperdepth (default value 20)
2617 - estimation/useleafts (default value TRUE)
2618 - estimation/ssg/nmaxsubtrees (default value -1)
2619 - estimation/ssg/nminnodeslastsplit (default value 0)
2620
2621- new parameter constraints/linear/extractcliques to turn clique extraction off
2622
2623- new emphasis setting emphasis/numerics to increase numerical stability of (mostly) presolving operations such as (multi-)aggregations at the cost of performance.
2624
2625- new parameters for treemodel:
2626 - new parameter branching/treemodel/enable to enable the treemodel in reliability pscost branching and possible
2627 future parts of the code where it could be used.
2628 - new parameter branching/treemodel/highrule to specify which branching rule to use when treemodel thinks the node
2629 is high in the tree.
2630 - new parameter branching/treemodel/lowrule to specify which branching rule to use when treemodel thinks the node
2631 is low in the tree.
2632 - new parameter branching/treemodel/height to specify at which (estimated) height a node is high or low in the tree.
2633 - new parameter branching/treemodel/filterhigh to specify whether to filter dominated candidates in nodes which are
2634 high in the tree.
2635 - new parameter branching/treemodel/filterlow to specify whether to filter dominated candidates in nodes which are
2636 low in the tree.
2637 - new parameter branching/treemodel/maxfpiter to specify the maximum number of fixed-point iterations to use when
2638 computing the ratio of a variable using the fixed-point method.
2639 - new parameter branching/treemodel/maxsvtsheight to specify the maximum height to compute the SVTS score exactly
2640 before approximating it using the ratio.
2641 - new parameter branching/treemodel/fallbackinf defines the fallback strategy to use when the tree size estimates
2642 obtained by SVTS are infinite.
2643 - new parameter branching/treemodel/fallbacknoprim defines the fallback strategy to use when no primal bound is known
2644 and thus SVTS would not be able to compute a tree size (it would be infinite).
2645 - new parameter branching/treemodel/smallpscost defines the value under which pscosts are considered too small to be
2646 the deciding factor for branching, in which case it may be better not to use the treemodel.
2647
2648- new parameters for symmetry handling constraint handlers to enforce that also non-model constraint are copied:
2649 - new parameter "constraints/orbisack/forceconscopy"
2650 - new parameter "constraints/orbitope/forceconscopy"
2651 - new parameter "constraints/symresack/forceconscopy"
2652
2653
2654### Data structures
2655
2656- small changes in constants of hash functions
2657- added fast 2-universal hash functions for two to seven 32bit elements with 32bit output
2658- extended SCIPpqueueCreate() by additional callback argument SCIP_DECL_PQUEUEELEMCHGPOS to catch position changes
2659- new methods SCIPpqueueDelPos() to delete elements at a specific position in the priority queue and SCIPpqueueFind() to
2660 find a specific position. It is recommended to track position changes using the new callback SCIP_DECL_PQUEUEELEMCHGPOS.
2661 In contrast, using SCIPpqueueFind() can be slow because it needs to compare the element it searches for
2662 with each slot in the queue.
2663
2664### Build system
2665
2666- The default value for DFLAGS in the non-cmake buildsystem has changed from -MM to -MMD. This will break the
2667 generation of depend.* files if that was done by a compiler call that relied on -MM. The new preferred way
2668 to handle compilation dependencies is to additionally use $(DFLAGS) when compiling the object files (.o) and
2669 to include the generated .d files in the Makefile, see also "Build system / Makefile" below.
2670
2671Unit tests
2672----------
2673 - new unit test for treemodel.
2674
2675Testing
2676-------
2677
2678 - fixed an issue that may have lead to wrong status reports in the evaluation scripts
2679
2680Build system
2681------------
2682
2683### Cmake
2684
2685- avoid problem with doubly defined object together with CPLEX
2686
2687### Makefile
2688
2689- Removed static object compilation dependency files (depend.*). If using a GCC compatible compiler, then dependency
2690 files are now dynamically created and updated during build. The new dependency files (*.d) reside next to each object
2691 file (.o) in the corresponding obj subdirectory.
2692- added support for building against Ipopt >= 3.13
2693- unify compiler switches for Intel compiler and avoid problem with doubly defined object together with CPLEX
2694
2695Fixed bugs
2696----------
2697
2698- fix and improve memory handling in symmetry computation
2699- fix shown number of applied conflicts in solving statistics
2700- fix wrongly skipping strong branching call and using old information if LP was solved with 0 iterations
2701- fix minor bug in cut score calculation
2702- fixed several bugs related to rounding locks of variables not being updated correctly
2703- small fix in cons_varbound.c to skip changing bounds of multi-aggregated variables in separation callback
2704- fixed issue in SCIPtightenVar* and SCIPinferVar* that occurs for small bound changes
2705- fixed rejecting minimal boundchange that changed sign of variable, even though SCIPisLb/UbBetter approved it
2706- fixed issue in generateCutNonConvex() which is triggered when adding quadratic constraints during the solving process
2707- fixed bug in freeing the reoptimization data if no problem exists
2708- fixed bug in SCIPreoptReleaseData() when freeing all stored constraints
2709- fixed bug when freeing the transformed problem via interactive shell if reoptimization is enabled
2710- fixed two issues related to (near-)redundant logicor constraints in presolving
2711- fixed counting of aggregations in XOR constraint handler
2712- fixed handling of unbounded solutions
2713- fixed update of LP size information when an LP error occured during probing
2714- handle special case of variable bound constraints during aggregating variables
2715- tighten sides of linear constraints before trying to upgrade them to more specialized constraints (knapsack, logic-or etc.) when calling SCIPupgradeConsLinear()
2716- fixed an issue in repair heuristic in the case of loose (noncolumn) variables
2717- allow user to correctly set heuristics/alns/(un)fixtol
2718- fixed an issue in heur_completesol which is triggered during bound widening of unbounded continuous variables
2719- fixed bug in cons_indicator if addopposite is true
2720- fixed bug in sepa_disjunctive: treat case that conflictgraph is empty
2721- added safety check in conversion to rational number to avoid overflow
2722- fixed bug in interval evaluation with power-operator in certain situations
2723- fixed behavior of SCIPmatrixCreate() regarding memory management and column generation
2724- SCIPmatrixCreate() returns complete=FALSE when locks do not add up
2725- fixed bug in sepa_oddcylce when variables are fixed
2726- fixed numerical issues related to tighter constraint sides in varbound constraint handler
2727- fixed update of watchedvars in logicor constraint handler in case of a restart during the tree
2728- fixed treatment of multi-aggregated variables in logicor constraint handler
2729- handle special case of redundant implications
2730- fixed numerical issue related to almost-0-values in pseudosolution conflict analysis
2731- fixed numerical issue related to very large greatest common dividers in linear constraint handler
2732- avoid using implications on multiaggregated variables when propagating implications
2733- fixed creation of (Lagrangian) variable bounds in the OBBT propagator
2734- fixed sorting of primal solutions
2735- fixed cleaning of clean buffer in conflict analysis
2736- avoid probing on variables with huge bounds in shift and propagate heuristic
2737- fix issue in printing solutions for variables that have been added by the dual sparsify presolver
2738- fix issue related to fixing redundant logic-or constraints after presolving
2739- fixed bug when parsing logic-or and and-constraints
2740- fixed wrong assert in updateLazyBounds()
2741- fixed bug in pricestore, which resulted in too many problem variables being added
2742- fixed bug in cons_knapsack where weight of clique was not reset after an infeasibility was detected
2743- fixed bug in presol_inttobinary which did not take into account that the aggregation could be rejected due to numerics
2744- fixed bug in debug solution mechanism in connection to variables created by presol_inttobinary
2745- fixed wrong indexing while undoing the implications from a redundant variable in SCIPshrinkDisjunctiveVarSet
2746- redundancy checks in SCIPnodeAddBoundinfer now take a possible change to an active variable into account
2747- fixed adding already added quadratic rows to NLP relaxation during solve
2748- fixed issue related to variable locks in the varbound constraint handler
2749- fixed bug in the quadratic constraint handler when changing infinite constraint sides
2750- fixed sorting of variables in linear constraint handler
2751- added additional checks to ensure numerical stability of dual proofs
2752- fixed a case when activities of a linear constraint got unreliable but where still used for reductions
2753- ensure that lhs <= rhs for linear constraints (without tolerances)
2754- make handling of read errors in SCIPfread() consistent between version with and without ZLIB
2755- correctly drop variable events in cons_indicator in restart
2756- fixed bug in cons_orbitope with upgrading of orbitope constraints
2757- additional checks in some presolvers for time limit being exceeded
2758- fixed bug in presolving of cons_varbound with multi-aggregated variables
2759- improve numerics in conflict analysis by using double-double arithmetic
2760- fixed bound acceptance condition to avoid inconsistencies
2761- fixed numerics in pseudoobj propagator by using double-double arithmetic
2762
2763Miscellaneous
2764-------------
2765
2766- modified display column for memory usage ("mem"), which reports the memory usage most of the time, but shows the creator name
2767 (heuristic, relaxation handler, LP relaxation, strong branching, pseudo solution) of every new incumbent solution. Together with this change,
2768 heuristic display characters have been unified to represent the type of the heuristic
2769 (diving, Large neighborhood search, propagation, etc.), see also type_heur.h.
2770- added assert that ensures that the locks of a variable have been decreased to 0 when it is freed
2771- added more output for completing a partial solution
2772- checks in debug mode that clean buffer memory is really clean when being freed are now disabled by default
2773- don't compute symmetries if reoptimization is enabled
2774- prefer integral values when fixing an almost-fixed continuous variable in the trivial presolver
2775- changed the name of the variable that is added by the OSiL reader to represent the quadratic or nonlinear parts of the objective function
2776- SCIP_EXPORT is now defined as __attribute__((__visibility__("default"))) if GCC and no SCIP config header is used
2777
2778@page RN6 Release notes for SCIP 6
2779
2780@section RN602 SCIP 6.0.2
2781*************************
2782
2783Features
2784--------
2785
2786- The abspower constraint handler now passes more accurate convexity
2787 information to the NLP relaxation.
2788
2789Examples and applications
2790-------------------------
2791
2792- added parsing functionality for optcumulative constraints in CIP format
2793
2794Interface changes
2795-----------------
2796
2797### Interfaces to external software
2798
2799- Updated the Mosek LP solver interface to support Mosek 9.0.
2800
2801Build system
2802------------
2803
2804### Cmake
2805
2806- new target to 'doc' to build documentation
2807- ctests now fail if parameter file not found
2808- add flag STATIC_GMP and improve GMP find module
2809- remove non-API methods from library (API methods use new macro SCIP_EXPORT)
2810- increase minimal required CMake version to 3.3
2811- correct paths and dependency information when installing SCIP
2812
2813Fixed bugs
2814----------
2815- fixed SCIP-Jack presolving bug that could lead to wrong results for Steiner arborescence problems
2816- fixed wrong unboundedness result in case not all constraints were already in the LP and enforcement was
2817 skipped because an optimal solution was found
2818- fixed wrong enforcement of constraints in the disjunction constraint handler
2819- fixed wrong behavior of concurrent solve ignoring initial solutions
2820- fixed bug in concurrent solve when problem was already solved in presolving
2821- aggregate non-artificial integer variable for XOR constraints with two binary variables and delete constraint
2822- copy the objective offset when copying the original problem
2823- fixed bug in SCIPlpiGetBInvARow in lpi_cpx using wrong size of resulting vector
2824- fixed quadratic runtime behavior in sepa_aggregation
2825- fixed statistics of separators
2826- improve numerical stability in varbound constraint handler by using double-double arithmetic
2827- fixed bug in propagation of dual proofs
2828- fixed bugs that arise for multiaggregated indicator variables by disallowing multiaggregation for them
2829- improve numerical stability in SCIPcomputeBilinEnvelope* by using double-double arithmetic
2830- fixed bug related to releasing pending bound changes in tree.c
2831- set STD FENV_ACCESS pragma to on in code that changes floating-point rounding mode
2832- disable GCC optimizations in main interval arithmetic code to prevent wrong optimizations
2833- fixed wrong assert in cons_xor concerning the variable type
2834- fixed different behavior of SCIPisLbBetter and SCIPisUbBetter between having NDEBUG defined or not
2835- correctly handle bound disjunctions in symmetry detection
2836- fixed issue in reliability branching related to the LP error flag not being reset
2837- fixed treatment of near-infinite bounds in shiftandpropagate's problem transformation
2838- fixed handling of infinite values in SCIPcomputeHyperplaneThreePoints()
2839- fixed comparisons of infinite values in heur_intshifting.c and heur_shifting.c
2840- fixed bug related to updating unprocessed cuts in the cutpool
2841- fixed bug related to enabling quadratic constraints during `CONSINITLP`
2842- add missing SCIP_EXPORT for functions used by GCG
2843- fixed memory leak and wrong initialization for trival cases in cons_symresack.c
2844- fixed bug with upgrading to packing/partitioning orbitopes
2845- fixed bug with the status while upgrading in presol_symbreak.c
2846- fixed wrong stage while clearing the conflict store
2847- fixed behavior of SCIPfixVar() by setting infeasible pointer to TRUE if fixval lies outside variable domain
2848- allow tightenVar() in SCIP_STAGE_PROBLEM stage
2849- fixed bug in cumulative constraint handler when separating the LP solution
2850- fixed issues with integer overflow in cumulative constraint handler
2851- fixed bug where the convexity of Benders' decomposition subproblems was checked even when users defined subproblem
2852 solving methods. Now, as per the documentation, the user must explicitly state whether the subproblem is convex
2853- fixed wrong indexing in heur_dualval
2854- fixed issue with basis status in SoPlex LPi
2855
2856Miscellaneous
2857-------------
2858
2859- statistics now output primal/dual bounds if objective limit is reached
2860- memory check in debug mode is now disabled by default
2861- message is now provided to the user to inform that automatic Benders' auxiliary variable lower bound computations are
2862 not activated when user defined subproblem solving methods are present
2863- corrected documentation of the primalgap in SCIP; describe when it will be infinite
2864
2865@section RN601 SCIP 6.0.1
2866*************************
2867
2868Features
2869--------
2870
2871- when using a debug solution every (multi-)aggregation will be checked w.r.t. this solution
2872
2873Performance improvements
2874------------------------
2875
2876- try greedy solution first before solving knapsack exactly using dynamic programming in SCIPsolveKnapsackExactly,
2877 compute greedy solution by weighted median selection.
2878- don't consider implied redcost by default in the reduced cost propagator
2879
2880Interface changes
2881-----------------
2882
2883### Deleted and changed API methods and macros
2884
2885- The preprocessor macro NO_CONFIG_HEADER now needs to be defined when
2886 including SCIP header files from a SCIP build or installation that
2887 has been build via the Makefile-only build system.
2888
2889- The following preprocessor macros have been renamed:
2890 WITH_ZLIB to SCIP_WITH_ZLIB, WITH_GMP to SCIP_WITH_GMP, WITH_READLINE
2891 to SCIP_WITH_READLINE, NO_SIGACTION to SCIP_NO_SIGACTION, NO_STRTOK_R
2892 to SCIP_NO_STRTOK_R, ROUNDING_FE to SCIP_ROUNDING_FE, ROUNDING_FP to
2893 SCIP_ROUNDING_FP, ROUNDING_MS to SCIP_ROUNDING_MS. Note, however, that
2894 the names of macros NO_RAND_R and NO_STRERROR_R have not been changed
2895 so far.
2896
2897### New API functions
2898
2899- SCIPhashmapInsertInt(), SCIPhashmapSetImageInt(), and SCIPhashmapGetImageInt() to use integer values as images in hashmaps
2900
2901### Command line interface
2902
2903- warn about coefficients in MPS files with absolute value larger than SCIP's value for infinity
2904
2905### Changed parameters
2906
2907- default clock type for timing is now wallclock
2908
2909Unit tests
2910----------
2911
2912- added unit tests for exact knapsack solving and (weighted) median selection algorithms
2913
2914Build system
2915------------
2916
2917### Cmake
2918
2919- add missing GMP dependency when compiling with SYM=bliss
2920- add DL library when linking to CPLEX to avoid linker errors
2921- new config.h header defining the current build configuration, e.g. SCIP_WITH_GMP
2922
2923Fixed bugs
2924----------
2925
2926- fixed handling of weights in cons_sos1 and cons_sos2 (NULL pointer to weights)
2927- fixed handling of unbounded LPs in SCIP and in several LPIs; added heuristic method to guess solution
2928- the STO reader is capable of handling scenarios defined using lower case "rhs"
2929- fixed OPB reader for instances without explicit plus signs
2930- correct dual solution values for bound constraints
2931- fixed recognition of variable with only one lock in cons_bivariate, cons_quadratic, and cons_nonlinear
2932- fixed update of constraint violations in solution repair in cons_bivariate, cons_quadratic, and cons_nonlinear
2933- print error message and terminate if matrix entries of a column are not consecutive in mps format
2934- fixed incorrect handling of fixed variables when transfer of cuts from LNS heuristic for Benders' decomposition
2935- fix returning local infeasible status by Ipopt interface if Ipopt finds problem locally infeasible
2936- skip attempt to apply fixings in linear constraint handler during solving stage as LP rows cannot change anymore
2937- fixed bug when reading >= indicator constraints in MPS format
2938- fix issue with nodes without domain changes if we ran into solution limit in prop_orbitalfixing
2939- fixed unresolved reference to CppAD's microsoft_timer() function on builds with MS/Intel compilers on Windows
2940- ignore implications added through SCIPaddVarImplication() that are redundant to global bounds also in the
2941 special case of an implication between two binary variables; also, use implications instead of cliques in the case
2942 of a binary implied variable with nonbinary active representative
2943- fixed bug with aggregated variables that are aggregated in propagation of cons_sos1
2944- fixed some special cases in SCIPselect/SCIPselectWeighted methods
2945- relaxed too strict assertion in Zirounding heuristic
2946- fixed the upgrade routine to XOR constraints: aggregate integer variable if its coefficient has the wrong sign
2947- fixed handling of nonartificial parity variables when deleting redundant XOR constraints
2948- earlier deletion of trivial XOR constraints (at most 1 operator left)
2949- fixed wrong hashmap accesses and added sanity check for the correct hashmap type
2950- avoid copying of unbounded solutions from sub-SCIPs as those cannot be checked completely
2951- corrected the output of the first LP value in case of branch-and-price
2952- fixed possible integer overflow, which led to wrong conclusion of infeasibility, in energetic reasoning of cons_cumulative.c
2953
2954Miscellaneous
2955-------------
2956
2957- do not scale linear constraints to integral coefficients
2958
2959@section RN600 SCIP 6.0.0
2960*************************
2961
2962Features
2963--------
2964
2965- new diving heuristic farkasdiving that dives into the direction of the pseudosolution and tries to construct Farkas-proofs
2966- new diving heuristic conflictdiving that considers locks from conflict constraints
2967- restructuring of timing of symmetry computation that allows to add symmetry handling components within presolving
2968- `lp/checkstability` is properly implemented for SoPlex LPI (spx2)
2969- new branching rule lookahead that evaluates potential child and grandchild nodes to determine a branching decision
2970- limits on the number of presolving rounds a presolver (maxrounds) or propagator/constraint handler (maxprerounds)
2971 participates in are now compared to the number of calls of the particular presolving method, not the number of
2972 presolving rounds in general, anymore
2973- new miscellaneous methods for constraints that have a one-row linear representation in pub_misc_linear.h
2974- a Benders' decomposition framework has been added. This framework provides the functionality for a user to solve a
2975 decomposed problem using Benders' decomposition. The framework includes classical optimality and feasibility cuts,
2976 integer optimality cuts and no-good cuts.
2977- add statistic that presents the number of resolves for instable LPs
2978- new readers for stochastic programming problems in SMPS format (reader_sto.h, reader_smps.h)
2979
2980Performance improvements
2981------------------------
2982
2983- cuts generated from certain quadratic constraints with convex feasible region are now global
2984- performance improvements for Adaptive Large Neighborhood Search heur_alns.c
2985 + all neighborhoods now start conservatively from maximum fixing rate
2986 + new default parameter settings for bandit selection parameters
2987 + no adjustment of minimum improvement by default
2988- improved bound tightening for some quadratic equations
2989- constraint handler checking order for original solutions has been modified to check those with negative check priority
2990 that don't need constraints after all other constraint handlers and constraints have been checked
2991- deactivate gauge cuts
2992
2993Examples and applications
2994-------------------------
2995
2996- new example `brachistochrone` in CallableLibrary examples collection; this example implements a discretized model to
2997 obtain the trajectory associated with the shortest time to go from point A to B for a particle under gravity only
2998- new example `circlepacking` in CallableLibrary examples collection; this example models two problems about packing
2999 circles of given radii into a rectangle
3000- new price-and-branch application for the ringpacking problem
3001- new stochastic capacitated facility location example demonstrating the use of the Benders' decomposition framework
3002
3003Interface changes
3004-----------------
3005
3006### New and changed callbacks
3007
3008- added parameter locktype to `SCIP_DECL_CONSLOCK` callback to indicate the type of variable locks
3009
3010### Deleted and changed API methods
3011
3012- Symmetry:
3013 + removed function SCIPgetTimingSymmetry() in presol_symmetry.h since this presolver does not compute symmetries independent
3014 of other components anymore
3015 + additional argument `recompute` to SCIPgetGeneratorsSymmetry() to allow recomputation of symmetries
3016
3017- Random generators:
3018 + the seed of SCIPinitializeRandomSeed() is now an unsigned int
3019 + the seed of SCIPsetInitializeRandomSeed() is now an unsigned int and it returns an unsigned int
3020 + new parameter for SCIPcreateRandom() to specify whether the global random seed shift should be used in the creation of
3021 the random number generator
3022
3023- Miscellaneous:
3024 + additional arguments `preferrecent`, `decayfactor` and `avglim` to SCIPcreateBanditEpsgreedy() to choose between
3025 weights that are simple averages or higher weights for more recent observations (the previous default).
3026 The last two parameters are used for a finer control of the exponential decay.
3027 + functions SCIPintervalSolveUnivariateQuadExpression(), SCIPintervalSolveUnivariateQuadExpressionPositive(), and
3028 SCIPintervalSolveUnivariateQuadExpressionPositiveAllScalar() now take an additional argument to specify already
3029 existing bounds on x, providing an entire interval ([-infinity,infinity]) gives previous behavior
6124 - added writing for pip files (linear, quadratic, polynomial nonlinear, polynomial abspower, polynomial bivariate, and
6125 and constraints)
6126 - CIP format variable characters defined, e.g. `SCIP_VARTYPE_INTEGER_CHAR`
6127 - Improved support for wbo format for weighted PBO problems, IBM's xml-solution
6128 format and pip and zimpl format for polynomial mixed-integer programs
6129 - New reader for (standard) bounds on variables
6130 - Extended reader for CIP models to handle various new constraints, including all types of linear constraints
6131 - flatzinc reader is now capable to read cumulative constraints
6132 - changed opb(/wbo) reader which now creates pseudoboolean constraints instead of linear- and and-constraints, only a
6133 non-linear objective will create and-constraints inside the reader and while reading a wbo file the topcost constraint
6134 is created as well
6135 - added clock for determine the time for reading
6136 - added reader for variable bounds (reader_bnd.{c,h})
6137 - Removed method SCIPreadSol(); call solution reading via SCIPreadProb() which calls the solution reader for .sol files.
6138
6139- Nonlinear:
6140 - Major extensions for nonlinear CIP, new option for n-ary branching on nonlinear variables (within pseudocost branching rule)
6141 - added BETA version of constraint handler for nonlinear constraints (cons_nonlinear.{c,h}) to handle nonlinear
6142 equations given by algebraic expressions using operands like addition, multiplication, power, exp, log, bivariate
6143 nonlinear constraints; currently no trigonometric functions
6144 - added BETA version of constraint handler for bivariate nonlinear constraints (cons_bivariate.{c,h}) to compute tight
6145 estimators for 1-convex and convex-concave bivariate nonlinear functions (given as expression tree)
6146 - the gams writer can now write nonlinear, abspower and bivariate constraints
6147 - Extended writer for GAMS and pip format to write more types of nonlinear constraints
6148 - the pip and zimpl reader now create nonlinear constraints for polynomials of degree > 2
6149
6150- Presolving:
6151 - new dual presolving methods in cons_setppc and cons_logicor
6152 - new presolving step `removeConstraintsDueToNegCliques` in locigor constraint handler which updates logicor constraints
6153 to setppc constraints if a negated clique inside this constraint exist, by default is off
6154 - new presolving step in cons_knapsack (detectRedundantVars, deleteRedundantVars) which determines redundant variables
6155 in knapsack constraint with or without using clique information
6156 - cons_logicor is now able to replace all aggregated variables in presolving by there active or negation of an active
6157 variable counterpart
6158 - prop_pseudoobj is now working in presolving as well
6159 - implement presolving in exitpre() in cons_orbitope and cons_indicator
6160
6161- Propagators:
6162 - added counter for number calls and timing for resolve propagation calls for constraint handler and propagators
6163 - Propagators are now also called in node presolving
6164 - the probing presolver presol_probing.{c.h} is now a propagator prop_probing.{c,h}, all corresponding parameters moved as well
6165 - the redcost separator sepa_redcost.{c.h} is now a propagator prop_redcost.{c,h}, all corresponding parameters moved as well
6166 - outsourced propAndSolve() method in solve.c which calls domain propagation and solving of the lp and relaxation
6167
6168- Statistic:
6169 - solutions which are given by the user from the outside are now marked by `#` in the output
6170 - the `Solving Time` is now spitted into presolving, solving and reading time
6171 - Presolvers section has new column `AddCons` which states the number of added constraint
6172 - Constraints section has new column named \#ResProp which show the number of resolve propagation calls of certain
6173 constraint handler
6174 - Constraint Timing section has a new column \#ResProp which states the time spend in resolve propagation method of the
6175 constraint handler
6176 - improved output of propagators in display statistics
6177 - new section `Propagator Timing` which shows the time spend in different callbacks of the propagator
6178 - rearranged first two columns of Propagators section; \#Propagate and \#ResProp stating the number of call for
6179 propagation and resolve propagation; the Time column is moved into the new section Propagator Timings
6180 - Constraints section has new column named `MaxNumber` which the maximum number of active constraint of a certain
6181 constraint handler
6182 - 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
6183 solving LPs with zero iterations (only refactorization)
6184 - The display of statistics for presolvers, propagators, constraints and LP solving has changed.
6185
6186Performance improvements
6187------------------------
6188
6189- Reorganized filtering process of separation storage (allows adding cuts for different solutions)
6190- Improved presolving for various constraint handlers
6191- Improved propagation methods for variable bound constraints
6192- Improved performance for quadratic constraints
6193- performance improvements in prop_vbounds
6194- child selection rules now get also applied when the relaxation value is equal to the bound changed in branching
6195- added dual reduction to cons_cumulative.c
6196- for continuous variables, the pseudo costs update and the pscost branching rule now use the same strategies for
6197 updating the pseudo costs and estimating the improvement in the LP bound
6198- only perform probing if the variables are locked
6199- performance and memory consumption improvements in xmlparse.c
6200- Improved knapsack cover cuts
6201- avoid very long separation times of LEWIs in cons_knapsack for very large minimal covers
6202- used SCIPallocMemoryArray() instead of SCIPallocBlockMemoryArray() which leads to fewer memory consumption in
6203 getLiftingSequence() in cons_knapsack, also improved cache use bei using an extra array instead blockmemory chunks
6204- switched FASTMIP from 1 to 2 for CPLEX and changed default pricing rule back to steepest edge pricing instead of
6205 quickstart steepest edge pricing
6206- made sorting method more robust
6207- LNS heuristics now use SCIPcopy() by default
6208- considering inactive variables in undercover heuristic; limiting effort for solving covering problem
6209- if during probing mode the LP relaxation is solved from scratch, e.g., when calling the shiftandpropagate heuristic
6210 before root node solving, then we clear the resulting LP state, since it might be a bad starting basis for the next
6211 solve of the LP relaxation (controlled by new parameter `lp/clearinitialprobinglp`)
6212- included LP simplifier into SoPlex LP interface, applied when solving from scratch (lpi_spx.cpp)
6213- new presolving steps in varbound constraint handler, tightening bounds, coefficients, sides and pairwise presolving
6214
6215Interface changes
6216-----------------
6217
6218- Miscellaneous:
6219 - The emphasis setting types now distinguish between plugin-type specific parameter settings (default, aggressive, fast, off),
6220 which are changed by SCIPsetHeuristics/Presolving/Separating(), and global emphasis settings (default, cpsolver, easycip,
6221 feasibility, hardlp, optimality, counter), which can be set using SCIPsetEmphasis().
6222
6223### New and changed callbacks
6224
6225- added propagator timings `SCIP_PROPTIMING_BEFORELP`, `SCIP_PROPTIMING_DURINGLPLOOP` and `SCIP_PROPTIMING_AFTERLPLOOP` for
6226 all propagation callbacks (see propagators and constraint handlers) which lead to calling the propagation methods of a
6227 propagator before the lp is solved, during the lp loop and after the lp solving loop
6228
6229- Conflict Analysis:
6230 - Added parameter `separate` to conflict handler callback method SCIP_DECL_CONFLICTEXEC() that defines whether the conflict
6231 constraint should be separated or not.
6232
6233- Constraint Handler:
6234 - The new constraint handler callback SCIP_DECL_CONSDELVARS() is called after variables were marked for deletion.
6235 This method is optional and only of interest if you are using SCIP as a branch-and-price framework. That means,
6236 you are generating new variables during the search. If you are not doing that just define the function pointer
6237 to be `NULL`.
6238 If this method gets implemented you should iterate over all constraints of the constraint handler and delete all
6239 variables that were marked for deletion by SCIPdelVar().
6240
6241- NLP Solver Interface:
6242 - The callbacks SCIP_DECL_NLPIGETSOLUTION() and SCIP_DECL_NLPISETINITIALGUESS() got new parameters to get/set values of
6243 dual variables.
6244 - The callback SCIP_DECL_NLPICOPY() now passes the block memory of the target SCIP as an additional parameter.
6245
6246- Presolving:
6247 - New parameters `isunbounded` and `isinfeasible` for presolving initialization (SCIP_DECL_CONSINITPRE(),
6248 SCIP_DECL_PRESOLINITPRE(), SCIP_DECL_PROPINITPRE()) and presolving deinitialization (SCIP_DECL_CONSEXITPRE(),
6249 SCIP_DECL_PRESOLEXITPRE(), SCIP_DECL_PROPEXITPRE()) callbacks of presolvers,
6250 constraint handlers and propagators, telling the callback whether the problem was already declared to be
6251 unbounded or infeasible. This allows to avoid expensive steps in these methods in case the problem is already
6252 solved, anyway.
6253
6254 Note, that the C++ methods
6255 - scip::ObjConshdlr::scip_presol() corresponding to SCIP_DECL_CONSPRESOL()
6256 - scip::ObjConshdlr::scip_initpre() corresponding to SCIP_DECL_CONSINITPRE()
6257 - scip::ObjPresol::scip_initpre() corresponding to SCIP_DECL_PRESOLINITPRE()
6258 - scip::ObjProp::scip_initpre() corresponding to SCIP_DECL_PROPINITPRE()
6259 - scip::ObjConshdlr::scip_exitpre() corresponding to SCIP_DECL_CONSEXITPRE()
6260 - scip::ObjPresol::scip_exitpre() corresponding to SCIP_DECL_PRESOLEXITPRE()
6261 - scip::ObjProp::scip_exitpre() corresponding to and SCIP_DECL_PROPEXITPRE()
6262 are virtual functions. That means, if you are not adding the new parameters, your code will still compile, but these methods are not executed.
6263 - Propagators are now also called in during presolving, this is supported by the new callback methods SCIP_DECL_PROPINITPRE(),
6264 SCIP_DECL_PROPEXITPRE(), and SCIP_DECL_PROPPRESOL().
6265 - The new parameters `nnewaddconss` and `naddconss` were added to the constraint handler callback method SCIP_DECL_CONSPRESOL()
6266 and the presolver callback method SCIP_DECL_PRESOLEXEC(). These parameters were also added to corresponding C++ wrapper
6267 class methods (scip_presol() in objconshdlr.h and scip_exec() in objpresol.h)
6268
6269- Problem Data:
6270 - The callback SCIP_DECL_PROBCOPY() got a new parameter `global` to indicate whether the global problem or a local version is copied.
6271
6272### Deleted and changed API methods
6273
6274- implemented SCIPlpiGetPrimalRay() in SoPlex interface that has become available with SoPlex version 1.5.0.2
6275- allowed calling SCIPgetRowSolActivity() in `SCIP_STAGE_SOLVED`, since LP is still available
6276- various extensions and modifications for expressions and expression trees (too much to state here)
6277- The result value `SCIP_NEWROUND` has been added, it allows a separator/constraint handler to start a new separation round
6278 (without previous calls to other separators/conshdlrs).
6279- SCIPcalcNodeselPriority() got a new parameter `branchdir`, which defines the type of branching that was performed: upwards, downwards, or fixed.
6280
6281- Constraint Handlers:
6282 - Method SCIPincludeQuadconsUpgrade() of quadratic constraint handler got new parameter `active` to indicate whether the upgrading method is active by default.
6283 - Method SCIPseparateRelaxedKnapsack() in knapsack constraint handler got new parameter `cutoff`, which is a pointer to store whether a cutoff was found.
6284
6285- Nonlinear expressions, relaxation, and solver interface:
6286 - SCIPcreateNLPSol() now creates a `SCIP_SOL` that is linked to the solution of the current NLP relaxation
6287 - Various types and functions dealing with polynomial expressions have been renamed to use the proper terms `monomial` and
6288 `polynomial` in nonlinear expressions (nlpi/∗expr*); results in many renamings of types, structs and methods.
6289 - The methods SCIPnlpGetObjective(), SCIPnlpGetSolVals(), and SCIPnlpGetVarSolVal() have been removed, use SCIPgetNLPObjval(),
6290 SCIPvarGetNLPSol() and SCIPcreateNLPSol() to retrieve NLP solution values instead.
6291 SCIPcreateNLPSol() now returns an error if NLP or NLP solution is not available
6292 - Removed methods SCIPmarkRequireNLP() and SCIPisNLPRequired(), because the NLP is now always constructed if nonlinearities
6293 are present.
6294 - SCIPgetNLP() has been removed and NLP-methods from pub_nlp.h have been moved to scip.h, which resulted in some renamings, too.
6295 - renamed SCIPexprtreeEvalSol() to SCIPevalExprtreeSol() and now located in scip.h.
6296 - renamed SCIPexprtreeEvalIntLocalBounds() to SCIPevalExprtreeLocalBounds() and now located in scip.h.
6297 - renamed SCIPexprtreeEvalIntGlobalBounds() to SCIPevalExprtreeGlobalBounds() and now located in scip.h.
6298 - The functions SCIPnlpiGetSolution() and SCIPnlpiSetInitialGuess() got additional arguments to get/set dual values.
6299 - The method SCIPgetNLPI() got a new parameter `nlpiproblem`, which is a pointer to store the NLP solver interface problem.
6300
6301- Timing:
6302 - SCIPincludeProp() got additional parameters to set the timing mask of the propagator and the new callbacks and parameters
6303 related to calling the propagator in presolving.
6304 - SCIPincludeConshdlr() got additional parameters to set the variable deletion callback function and the timing mask for
6305 propagation.
6306 - removed parameters timelimit and memorylimit from SCIPapplyRens()
6307 - The parameters `timelimit` and `memorylimit` were removed from SCIPapplyRens().
6308
6309- Problem Data:
6310 - The method SCIPcopyProb() got a new parameter `global` to indicate whether the global problem or a local version is copied.
6311
6312- Writing and Parsing Constraints:
6313 - The methods SCIPwriteVarName(), SCIPwriteVarsList(), and SCIPwriteVarsLinearsum() got a new boolean parameter `type`
6314 that indicates whether the variable type should be written or not.
6315 - The methods SCIPparseVarName() and SCIPparseVarsList() got a new output parameter `endptr` that is filled with the position
6316 where the parsing stopped.
6317 - The method SCIPwriteVarsList() got additionally a new parameter `delimiter` that defines the character which is used for delimitation.
6318
6319- Variables:
6320 - SCIPmarkDoNotMultaggrVar()/SCIPvarMarkDoNotMultaggr() now allow to mark negated and aggregated variables
6321 - SCIPgetVarCopy() got a new parameter `success` that will be FALSE if method is called after problem creation stage and no hash map is
6322 given or no image for the given variable is contained in the given hash map.
6323 - SCIPchgVarType() got an extra boolean parameter to store if infeasibility is recognized while upgrading a variable from continuous
6324 type to an integer type.
6325 - SCIPdelVar() got a new parameter `deleted`, which stores whether the variable was successfully marked to be deleted.
6326
6327### New API functions
6328
6329- information about the quality of the solution of an LP (currently the condition number of the basis matrix) can now be:
6330 + requested from the LPI (currently only available for CPLEX): methods SCIPlpiGetRealSolQuality() and
6331 + SCIPprintLPSolutionQuality() command display lpsolquality in interactive shell display column lpcond to show
6332 + estimate on condition number, if available
6333- SCIPround() and SCIPfeasRound() to round to nearest integer
6334- SCIPsortRealRealIntInt() and corresponding sorting/inserting/deleting methods in pub_misc.h and necessary defines in misc.c
6335- SCIPsortRealIntLong(), SCIPsortPtrPtrRealInt() and corresponding sorting/inserting/deleting methods in
6336 pub_misc.h and necessary defines in misc.c
6337- SCIPcomputeLPRelIntPoint() to compute relative interior point of the current LP
6338- SCIPstartSolvingTime() and SCIPstopSolvingTime() which can be used to start or stop the solving time clock
6339- SCIPstrToRealValue() and SCIPstrCopySection() in pub_misc.h; these methods can be used to convert a string
6340 into a `SCIP_Real` value and to copy a substring.
6341- SCIPgetBinvarRepresentatives() which gets binary variables that are equal to some given binary variables,
6342 and which are either active, fixed, or multi-aggregated, or the negated variables of active, fixed, or multi-aggregated variables
6343- SCIPhasPrimalRay() and SCIPgetPrimalRayVal() that return whether a primal ray is stored and which value a
6344 given variable has in the primal ray, respectively
6345- SCIPsetConsModifiable()
6346- SCIPsetParam() which is a generic parameter setter method, independent of the parameter type
6347- SCIPpropInitpre(), SCIPpropExitpre(), SCIPpropPresol() which initializes, exists and executes the presolving phase
6348- SCIProwGetAge() to access the age of a row (pub_lp.h/lp.c)
6349- SCIPsolGetOrigObj() in pub_sol.h which returns for a solution in the original problem space the objective value
6350- SCIPretransformSol() in scip.h that allows to retransform a solution to the original space
6351- SCIPlpiClearState() to LP interfaces for clearing basis information in the LP solver
6352- SCIPgetSubscipDepth() to access the depth of the current SCIP as a copied subproblem
6353- SCIPdebugAddSolVal() and SCIPdebugGetSolVal() to add/get values to/from a debug solution
6354- SCIPsepastoreRemoveInefficaciousCuts() to remove non-efficious cuts from the separation storage
6355
6356- Nodes:
6357 - SCIPnodeGetParent() to get parent node of a node
6358 - SCIPnodesSharePath() in pub_tree.h that determines whether two nodes are on the same leaf-root path
6359 - SCIPnodesGetCommonAncestor() in pub_tree.h that finds the common ancestor node for two given nodes
6360
6361- Read and Write:
6362 - SCIPgetReadingTime() which returns the time for reading in seconds
6363 - SCIPparseVarsLinearsum(), SCIPparseVarsPolynomial() and SCIPwriteVarsPolynomial() and for writing and
6364 parsing polynomials in constraint handler writing/parsing methods
6365
6366- Memory:
6367 - SCIPcreateMesshdlrPThreads() and SCIPfreeMesshdlrPThreads() for allocating and deleting necessary memory
6368 for message handlers for parallel pthread version
6369 - SCIPallocClearMemoryArray() and BMSallocClearMemoryArray() for allocating cleared memory arrays in scip.h and memory.h
6370
6371- Intervals:
6372 - SCIPintervalPowerScalarInverse() to solve an equation y = x^p for given bounds on y and scalar exponent p
6373 - SCIPintervalQuadBivar() to compute tight bounds on a bivariate quadratic form
6374 - SCIPintervalSolveBivariateQuadExpressionAllScalar() to compute tight bounds on the solutions of a bivariate quadratic equation
6375
6376- Variables:
6377 - SCIPcomputeVarCurrent{L,U}b{Local,Global}() to compute local or global lower or upper bounds of a
6378 multiaggregated variable from the bounds of the aggregation variables
6379 - SCIPbranchVarValNary() for n-ary variable branching
6380 - SCIPgetNegatedVars() which returns all negated variables for a given array of variables, if the negated
6381 variables are not existing yet, they will be created
6382 - SCIPgetNTotalVars() that returns the total number of created vars, icluding variables that were deleted in the meantime
6383 - SCIPvarGetHashkey(), SCIPvarIsHashkeyEq(), SCIPvarGetHashkeyVal() in pub_var.h which can be used for `SCIP_HASHTABLE` of variables
6384 - SCIPvarGetNBdchgInfosLb() and SCIPvarGetNBdchgInfosUb() in pub_var.h returning the number of lower or upper bound changes on the active path
6385 - SCIPvarGetBdchgInfoLb() and SCIPvarGetBdchgInfoUb() returning the bound change information at the given position
6386 - SCIPvarMarkDeletable() to mark a variable to be deletable completely from the problem (for
6387 branch-and-price); can only be called before the variable is added to the problem
6388 - SCIPvarMarkNotDeletable() that marks a variable to be non-deleteable (used within SCIP for forbidding
6389 deletion of variables contained in solution, LP bases, (multi)aggregation, ...)
6390 - SCIPvarIsDeletable() that returns whether a variable is marked to be deletable (each variable is per default non-deletable)
6391
6392- NLP:
6393 - SCIPgetNLPVarsNonlinearity() to get for each variable in the NLP the number of NLP rows in which this variable appears in a nonlinear way
6394 - SCIPnlrowGetDualsol(), SCIPgetNLPVarsLbDualsol(), SCIPgetNLPVarsUbDualsol() to retrieve dual values from an NLP solution
6395 - SCIPgetNLPFracVars() to get the fractional variables in an NLP solution
6396
6397- Propagator:
6398 - SCIPpropSetPresolPriority() which changes the presolving priority of a given propagator
1.14.0