Scippy

SCIP

Solving Constraint Integer Programs

Detailed Description

propagator for handling symmetries

Author
Marc Pfetsch
Thomas Rehn
Christopher Hojny
Fabian Wegscheider

This propagator combines the following symmetry handling functionalities:

  • It allows to compute symmetries of the problem and to store this information in adequate form. The symmetry information can be accessed through external functions.
  • It allows to add the following symmetry breaking constraints:
    • symresack constraints, which separate minimal cover inequalities
    • orbitope constraints, if special symmetry group structures are detected
  • It allows to apply orbital fixing.

Symmetry Computation

The following comments apply to symmetry computation.

  • The generic functionality of the compute_symmetry.h interface is used.
  • We treat implicit integer variables as if they were continuous/real variables. The reason is that there is currently no distinction between implicit integer and implicit binary. Moreover, currently implicit integer variables hurt our code more than continuous/real variables (we basically do not handle integral variables at all).
  • We do not copy symmetry information, since it is not clear how this information transfers. Moreover, copying symmetry might inhibit heuristics. But note that solving a sub-SCIP might then happen without symmetry information!

Symmetry Handling Constraints

The following comments apply to adding symmetry handling constraints.

  • The code automatically detects whether symmetry substructures like symresacks or orbitopes are present and possibly adds the corresponding constraints.
  • If orbital fixing is active, only orbitopes are added (if present) and no symresacks.
  • We try to compute symmetry as late as possible and then add constraints based on this information.
  • Currently, we only allocate memory for pointers to symresack constraints for group generators. If further constraints are considered, we have to reallocate memory.

Orbital Fixing

Orbital fixing is implemented as introduced by
F. Margot: Exploiting orbits in symmetric ILP. Math. Program., 98(1-3):3–21, 2003.

The method computes orbits of variables with respect to the subgroup of the symmetry group that stabilizes the variables globally fixed or branched to 1. Then one can fix all variables in an orbit to 0 or 1 if one of the other variables in the orbit is fixed to 0 or 1, respectively. Different from Margot, the subgroup is obtained by filtering out generators that do not individually stabilize the variables branched to 1.

Precondition
All variable fixings applied by other components are required to be strict, i.e., if one variable is fixed to a certain value v, all other variables in the same variable orbit can be fixed to v as well, c.f.
F. Margot: Symmetry in integer linear programming. 50 Years of Integer Programming, 647-686, Springer 2010.

To illustrate this, consider the example \(\max\{x_1 + x_2 : x_1 + x_2 \leq 1, Ay \leq b, (x,y) \in \{0,1\}^{2 + n}\} \). Since \(x_1\) and \(x_2\) are independent from the remaining problem, the setppc constraint handler may fix \((x_1,x_2) = (1,0)\). However, since both variables are symmetric, this setting is not strict (if it was strict, both variables would have been set to the same value) and orbital fixing would declare this subsolution as infeasible (there exists an orbit of non-branching variables that are fixed to different values). To avoid this situation, we have to assume that all non-strict settings fix variables globally, i.e., we can take care of it by taking variables into account that have been globally fixed to 1. In fact, it suffices to consider one kind of global fixings since stabilizing one kind prevents an orbit to contain variables that have been fixed globally to different values.

Precondition
All non-strict settings are global settings, since otherwise, we cannot (efficiently) take care of them.
No non-strict setting algorithm is interrupted early (e.g., by a time or iteration limit), since this may lead to wrong decisions by orbital fixing as well. For example, if cons_setppc in the above toy example starts by fixing \(x_2 = 0\) and is interrupted afterwards, orbital fixing detects that the orbit \(\{x_1, x_2\}\) contains one variable that is fixed to 0, and thus, it fixes \(x_1\) to 0 as well. Thus, after these reductions, every feasible solution has objective 0 which is not optimal. This situation would not occur if the non-strict setting is complete, because then \(x_1\) is globally fixed to 1, and thus, is stabilized in orbital fixing.

Note that orbital fixing might lead to wrong results if it is called in repropagation of a node, because the path from the node to the root might have been changed. Thus, the stabilizers of global 1-fixing and 1-branchings of the initial propagation and repropagation might differ, which may cause conflicts. For this reason, orbital fixing cannot be called in repropagation.

Note
If, besides orbital fixing, also symmetry handling constraints shall be added, orbital fixing is only applied to symmetry components that are not handled by orbitope constraints.

Cuts derived from the Schreier Sims table

SST cuts have been introduced by
D. Salvagnin: Symmetry Breaking Inequalities from the Schreier-Sims table. CPAIOR 2018 Proceedings, 521-529, 2018.

These inequalities are computed as follows. Throughout these procedure a set of so-called leaders is maintained. Initially the set of leaders is empty. In a first step, select a variable \(x_i\) and compute its orbit w.r.t. the symmetry group of the mixed-integer program. For each variable \(x_j\) in the orbit of \(x_i\), the inequality \(x_i \geq x_j\) is a valid symmetry handling inequality, which can be added to the mixed-integer program. We call \(x_i\) the leader of this inequality. Add the leader \(x_i\) to the set of leaders and compute the pointwise stabilizer of the leader set. In the next step, select a new variable, compute its orbit w.r.t. the stabilizer group of the leaders, add the inequalities based on this orbit, and add the new leader to the set of leaders. This procedure is iterated until the pointwise stabilizer group of the leaders has become trivial.

Definition in file prop_symmetry.c.

#include <scip/cons_linear.h>
#include <scip/cons_knapsack.h>
#include <scip/cons_varbound.h>
#include <scip/cons_setppc.h>
#include <scip/cons_and.h>
#include <scip/cons_logicor.h>
#include <scip/cons_or.h>
#include <scip/cons_orbitope.h>
#include <scip/cons_symresack.h>
#include <scip/cons_xor.h>
#include <scip/cons_linking.h>
#include <scip/cons_bounddisjunction.h>
#include <scip/cons_nonlinear.h>
#include <scip/pub_expr.h>
#include <scip/misc.h>
#include <scip/scip_datastructures.h>
#include <scip/prop_symmetry.h>
#include <symmetry/compute_symmetry.h>
#include <scip/symmetry.h>
#include <string.h>

Go to the source code of this file.

Data Structures

struct  SYM_Sortrhstype
 
struct  SYM_Sortgraphcompvars
 

Macros

#define PROP_NAME   "symmetry"
 
#define PROP_DESC   "propagator for handling symmetry"
 
#define PROP_TIMING   SCIP_PROPTIMING_BEFORELP
 
#define PROP_PRIORITY   -1000000
 
#define PROP_FREQ   1
 
#define PROP_DELAY   FALSE
 
#define PROP_PRESOL_PRIORITY   -10000000
 
#define PROP_PRESOLTIMING   SCIP_PRESOLTIMING_EXHAUSTIVE /* timing of the presolving method (fast, medium, or exhaustive) */
 
#define PROP_PRESOL_MAXROUNDS   -1
 
#define DEFAULT_MAXGENERATORS   1500
 
#define DEFAULT_CHECKSYMMETRIES   FALSE
 
#define DEFAULT_DISPLAYNORBITVARS   FALSE
 
#define DEFAULT_USECOLUMNSPARSITY   FALSE
 
#define DEFAULT_DOUBLEEQUATIONS   FALSE
 
#define DEFAULT_COMPRESSSYMMETRIES   TRUE
 
#define DEFAULT_COMPRESSTHRESHOLD   0.5
 
#define DEFAULT_SYMFIXNONBINARYVARS   FALSE
 
#define DEFAULT_ONLYBINARYSYMMETRY   TRUE
 
#define DEFAULT_CONSSADDLP   TRUE
 
#define DEFAULT_ADDSYMRESACKS   FALSE
 
#define DEFAULT_DETECTORBITOPES   TRUE
 
#define DEFAULT_DETECTSUBGROUPS   TRUE
 
#define DEFAULT_ADDWEAKSBCS   TRUE
 
#define DEFAULT_ADDSTRONGSBCS   FALSE
 
#define DEFAULT_ADDCONSSTIMING   2
 
#define DEFAULT_MAXNCONSSSUBGROUP   500000
 
#define DEFAULT_USEDYNAMICPROP   TRUE
 
#define DEFAULT_PREFERLESSROWS   TRUE
 
#define DEFAULT_OFSYMCOMPTIMING   2
 
#define DEFAULT_PERFORMPRESOLVING   FALSE
 
#define DEFAULT_RECOMPUTERESTART   0
 
#define DEFAULT_SSTTIEBREAKRULE   1
 
#define DEFAULT_SSTLEADERRULE   0
 
#define DEFAULT_SSTLEADERVARTYPE   14
 
#define DEFAULT_ADDCONFLICTCUTS   TRUE
 
#define DEFAULT_SSTADDCUTS   TRUE
 
#define DEFAULT_SSTMIXEDCOMPONENTS   TRUE
 
#define EVENTHDLR_SYMMETRY_NAME   "symmetry"
 
#define EVENTHDLR_SYMMETRY_DESC   "filter global variable fixing event handler for orbital fixing"
 
#define TABLE_NAME_ORBITALFIXING   "orbitalfixing"
 
#define TABLE_DESC_ORBITALFIXING   "orbital fixing statistics"
 
#define TABLE_POSITION_ORBITALFIXING   7001
 
#define TABLE_EARLIEST_ORBITALFIXING   SCIP_STAGE_SOLVING
 
#define MAXGENNUMERATOR   64000000
 
#define SCIP_SPECIALVAL   1.12345678912345e+19
 
#define COMPRESSNVARSLB   25000
 
#define ISSYMRETOPESACTIVE(x)   (((unsigned) x & SYM_HANDLETYPE_SYMBREAK) != 0)
 
#define ISORBITALFIXINGACTIVE(x)   (((unsigned) x & SYM_HANDLETYPE_ORBITALFIXING) != 0)
 
#define ISSSTACTIVE(x)   (((unsigned) x & SYM_HANDLETYPE_SST) != 0)
 
#define ISSSTBINACTIVE(x)   (((unsigned) x & SCIP_SSTTYPE_BINARY) != 0)
 
#define ISSSTINTACTIVE(x)   (((unsigned) x & SCIP_SSTTYPE_INTEGER) != 0)
 
#define ISSSTIMPLINTACTIVE(x)   (((unsigned) x & SCIP_SSTTYPE_IMPLINT) != 0)
 
#define ISSSTCONTACTIVE(x)   (((unsigned) x & SCIP_SSTTYPE_CONTINUOUS) != 0)
 

Typedefs

typedef struct SCIP_NodeData SCIP_NODEDATA
 
typedef struct SYM_Sortrhstype SYM_SORTRHSTYPE
 
typedef struct SYM_Sortgraphcompvars SYM_SORTGRAPHCOMPVARS
 

Functions

static SCIP_DECL_EVENTEXEC (eventExecSymmetry)
 
static SCIP_DECL_TABLEOUTPUT (tableOutputOrbitalfixing)
 
static SCIP_DECL_TABLEFREE (tableFreeOrbitalfixing)
 
static SCIP_DECL_HASHGETKEY (SYMhashGetKeyVartype)
 
static SCIP_DECL_HASHKEYEQ (SYMhashKeyEQVartype)
 
static SCIP_DECL_HASHKEYVAL (SYMhashKeyValVartype)
 
static SCIP_DECL_SORTINDCOMP (SYMsortRhsTypes)
 
static SCIP_DECL_SORTINDCOMP (SYMsortMatCoef)
 
static SCIP_DECL_SORTINDCOMP (SYMsortGraphCompVars)
 
static SCIP_Bool checkSymmetryDataFree (SCIP_PROPDATA *propdata)
 
static SCIP_Bool isLeadervartypeCompatible (SCIP_VAR *var, int leadervartype)
 
static SCIP_RETCODE setSymmetryMethodEnabledValues (SCIP_PROPDATA *propdata)
 
static SCIP_RETCODE freeSymmetryData (SCIP *scip, SCIP_PROPDATA *propdata)
 
static SCIP_Bool SymmetryFixVar (SYM_SPEC fixedtype, SCIP_VAR *var)
 
static SCIP_RETCODE getActiveVariables (SCIP *scip, SCIP_VAR ***vars, SCIP_Real **scalars, int *nvars, SCIP_Real *constant, SCIP_Bool transformed)
 
static SCIP_RETCODE collectCoefficients (SCIP *scip, SCIP_Bool doubleequations, SCIP_VAR **linvars, SCIP_Real *linvals, int nlinvars, SCIP_Real lhs, SCIP_Real rhs, SCIP_Bool istransformed, SYM_RHSSENSE rhssense, SYM_MATRIXDATA *matrixdata, int *nconssforvar)
 
static SCIP_RETCODE checkSymmetriesAreSymmetries (SCIP *scip, SYM_SPEC fixedtype, SYM_MATRIXDATA *matrixdata, int nperms, int **perms)
 
static int getNSymhandableConss (SCIP *scip, SCIP_CONSHDLR *conshdlr_nonlinear)
 
static SCIP_Bool hasNonlinearConstraints (SCIP_PROPDATA *propdata)
 
static SCIP_RETCODE setSymmetryData (SCIP *scip, SCIP_VAR **vars, int nvars, int nbinvars, SCIP_VAR ***permvars, int *npermvars, int *nbinpermvars, int **perms, int nperms, int *nmovedvars, SCIP_Bool *binvaraffected, SCIP_Bool usecompression, SCIP_Real compressthreshold, SCIP_Bool *compressed)
 
static SCIP_RETCODE computeSymmetryGroup (SCIP *scip, SCIP_Bool doubleequations, SCIP_Bool compresssymmetries, SCIP_Real compressthreshold, int maxgenerators, SYM_SPEC fixedtype, SCIP_Bool local, SCIP_Bool checksymmetries, SCIP_Bool usecolumnsparsity, SCIP_CONSHDLR *conshdlr_nonlinear, int *npermvars, int *nbinpermvars, SCIP_VAR ***permvars, int *nperms, int *nmaxperms, int ***perms, SCIP_Real *log10groupsize, int *nmovedvars, SCIP_Bool **isnonlinvar, SCIP_Bool *binvaraffected, SCIP_Bool *compressed, SCIP_Bool *success)
 
static SCIP_RETCODE determineSymmetry (SCIP *scip, SCIP_PROPDATA *propdata, SYM_SPEC symspecrequire, SYM_SPEC symspecrequirefixed)
 
static SCIP_RETCODE checkTwoCyclePermsAreOrbitope (SCIP *scip, SCIP_VAR **permvars, int npermvars, int **perms, int *activeperms, int ntwocycles, int nactiveperms, int **orbitopevaridx, int *columnorder, int *nusedelems, int *nusedcols, SCIP_Shortbool *rowisbinary, SCIP_Bool *isorbitope, SCIP_Shortbool *activevars)
 
static SCIP_RETCODE chooseOrderOfGenerators (SCIP *scip, SCIP_PROPDATA *propdata, int compidx, int **genorder, int *ntwocycleperms)
 
static SCIP_RETCODE buildSubgroupGraph (SCIP *scip, SCIP_PROPDATA *propdata, int *genorder, int ntwocycleperms, int compidx, int **graphcomponents, int **graphcompbegins, int **compcolorbegins, int *ngraphcomponents, int *ncompcolors, int **usedperms, int *nusedperms, int usedpermssize, SCIP_Shortbool *permused)
 
static SCIP_RETCODE addOrbitopeSubgroup (SCIP *scip, SCIP_PROPDATA *propdata, int *usedperms, int nusedperms, int *compcolorbegins, int *graphcompbegins, int *graphcomponents, int graphcoloridx, int nrows, int ncols, int *firstvaridx, int *compidxfirstrow, int **lexorder, int *nvarslexorder, int *maxnvarslexorder, SCIP_Bool mayinteract, SCIP_Bool *success)
 
static SCIP_RETCODE addStrongSBCsSubgroup (SCIP *scip, SCIP_PROPDATA *propdata, int *graphcompbegins, int *graphcomponents, int graphcompidx, SCIP_Bool storelexorder, int **lexorder, int *nvarsorder, int *maxnvarsorder)
 
static SCIP_RETCODE addWeakSBCsSubgroup (SCIP *scip, SCIP_PROPDATA *propdata, int *compcolorbegins, int *graphcompbegins, int *graphcomponents, int ncompcolors, int *chosencomppercolor, int *firstvaridxpercolor, int symgrpcompidx, int *naddedconss, SCIP_Bool storelexorder, int **lexorder, int *nvarsorder, int *maxnvarsorder)
 
static SCIP_RETCODE adaptSymmetryDataSST (SCIP *scip, int **origperms, int **modifiedperms, int nperms, SCIP_VAR **origpermvars, SCIP_VAR **modifiedpermvars, int npermvars, int *leaders, int nleaders)
 
static int getNOrbitopesInComp (SCIP_VAR **permvars, int *graphcomponents, int *graphcompbegins, int *compcolorbegins, int ncompcolors, int symcompsize)
 
static SCIP_RETCODE detectAndHandleSubgroups (SCIP *scip, SCIP_PROPDATA *propdata)
 
static SCIP_RETCODE SCIPsortOrbitope (SCIP *scip, int **orbitopevaridx, SCIP_VAR ***vars, int nrows, int ncols)
 
static SCIP_RETCODE detectOrbitopes (SCIP *scip, SCIP_PROPDATA *propdata, int *components, int *componentbegins, int ncomponents)
 
static SCIP_RETCODE updateSymInfoConflictGraphSST (SCIP *scip, SCIP_DIGRAPH *conflictgraph, SCIP_VAR **graphvars, int ngraphvars, SCIP_VAR **permvars, int npermvars, SCIP_Bool onlypermvars, SCIP_HASHMAP *varmap, int *orbits, int *orbitbegins, int norbits)
 
static SCIP_RETCODE createConflictGraphSST (SCIP *scip, SCIP_DIGRAPH **conflictgraph, SCIP_VAR **graphvars, int ngraphvars, SCIP_Bool onlypermvars, SCIP_HASHMAP *permvarmap, SCIP_Bool *success)
 
static SCIP_RETCODE freeConflictGraphSST (SCIP *scip, SCIP_DIGRAPH **conflictgraph, int nnodes)
 
static SCIP_RETCODE addSymresackConss (SCIP *scip, SCIP_PROP *prop, int *components, int *componentbegins, int ncomponents)
 
static SCIP_RETCODE addSSTConssOrbitAndUpdateSST (SCIP *scip, SCIP_DIGRAPH *conflictgraph, SCIP_PROPDATA *propdata, SCIP_VAR **permvars, int *orbits, int *orbitbegins, int orbitidx, int orbitleaderidx, SCIP_Shortbool *orbitvarinconflict, int norbitvarinconflict, int *nchgbds, SCIP_Bool useconflictgraph)
 
static SCIP_RETCODE selectOrbitLeaderSSTConss (SCIP *scip, SCIP_DIGRAPH *conflictgraph, SCIP_VAR **graphvars, int ngraphvars, SCIP_HASHMAP *varmap, SCIP_VAR **permvars, int npermvars, int *orbits, int *orbitbegins, int norbits, int leaderrule, int tiebreakrule, SCIP_VARTYPE leadervartype, int *orbitidx, int *leaderidx, SCIP_Shortbool *orbitvarinconflict, int *norbitvarinconflict, SCIP_Bool useconflictgraph, SCIP_Bool *success)
 
static SCIP_RETCODE addSSTConss (SCIP *scip, SCIP_PROPDATA *propdata, int *nchgbds)
 
static SCIP_RETCODE tryAddSymmetryHandlingConss (SCIP *scip, SCIP_PROP *prop, int *nchgbds, SCIP_Bool *earlyterm)
 
static SCIP_RETCODE performOrbitalFixing (SCIP *scip, SCIP_VAR **permvars, int npermvars, int *orbits, int *orbitbegins, int norbits, SCIP_Bool *infeasible, int *nfixedzero, int *nfixedone)
 
static SCIP_RETCODE computeBranchingVariables (SCIP *scip, int nvars, SCIP_HASHMAP *varmap, SCIP_Shortbool *bg1, int *bg1list, int *nbg1)
 
static SCIP_RETCODE propagateOrbitalFixing (SCIP *scip, SCIP_PROPDATA *propdata, SCIP_Bool *infeasible, int *nprop)
 
static SCIP_DECL_PROPINITPRE (propInitpreSymmetry)
 
static SCIP_DECL_PROPEXITPRE (propExitpreSymmetry)
 
static SCIP_DECL_PROPPRESOL (propPresolSymmetry)
 
static SCIP_DECL_PROPEXEC (propExecSymmetry)
 
static SCIP_DECL_PROPEXIT (propExitSymmetry)
 
static SCIP_DECL_PROPRESPROP (propRespropSymmetry)
 
static SCIP_DECL_PROPFREE (propFreeSymmetry)
 
SCIP_RETCODE SCIPincludePropSymmetry (SCIP *scip)
 
SCIP_RETCODE SCIPgetSymmetry (SCIP *scip, int *npermvars, SCIP_VAR ***permvars, SCIP_HASHMAP **permvarmap, int *nperms, int ***perms, int ***permstrans, SCIP_Real *log10groupsize, SCIP_Bool *binvaraffected, int **components, int **componentbegins, int **vartocomponent, int *ncomponents)
 
SCIP_Bool SCIPisOrbitalfixingEnabled (SCIP *scip)
 
int SCIPgetSymmetryNGenerators (SCIP *scip)
 

Macro Definition Documentation

◆ PROP_NAME

◆ PROP_DESC

#define PROP_DESC   "propagator for handling symmetry"

Definition at line 163 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ PROP_TIMING

#define PROP_TIMING   SCIP_PROPTIMING_BEFORELP

propagation timing mask

Definition at line 164 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ PROP_PRIORITY

#define PROP_PRIORITY   -1000000

propagator priority

Definition at line 165 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ PROP_FREQ

#define PROP_FREQ   1

propagator frequency

Definition at line 166 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ PROP_DELAY

#define PROP_DELAY   FALSE

should propagation method be delayed, if other propagators found reductions?

Definition at line 167 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ PROP_PRESOL_PRIORITY

#define PROP_PRESOL_PRIORITY   -10000000

priority of the presolving method (>= 0: before, < 0: after constraint handlers)

Definition at line 169 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ PROP_PRESOLTIMING

#define PROP_PRESOLTIMING   SCIP_PRESOLTIMING_EXHAUSTIVE /* timing of the presolving method (fast, medium, or exhaustive) */

Definition at line 170 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ PROP_PRESOL_MAXROUNDS

#define PROP_PRESOL_MAXROUNDS   -1

maximal number of presolving rounds the presolver participates in (-1: no limit)

Definition at line 171 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ DEFAULT_MAXGENERATORS

#define DEFAULT_MAXGENERATORS   1500

limit on the number of generators that should be produced within symmetry detection (0 = no limit)

Definition at line 175 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ DEFAULT_CHECKSYMMETRIES

#define DEFAULT_CHECKSYMMETRIES   FALSE

Should all symmetries be checked after computation?

Definition at line 176 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ DEFAULT_DISPLAYNORBITVARS

#define DEFAULT_DISPLAYNORBITVARS   FALSE

Should the number of variables affected by some symmetry be displayed?

Definition at line 177 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ DEFAULT_USECOLUMNSPARSITY

#define DEFAULT_USECOLUMNSPARSITY   FALSE

Should the number of conss a variable is contained in be exploited in symmetry detection?

Definition at line 178 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ DEFAULT_DOUBLEEQUATIONS

#define DEFAULT_DOUBLEEQUATIONS   FALSE

Double equations to positive/negative version?

Definition at line 179 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ DEFAULT_COMPRESSSYMMETRIES

#define DEFAULT_COMPRESSSYMMETRIES   TRUE

Should non-affected variables be removed from permutation to save memory?

Definition at line 180 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ DEFAULT_COMPRESSTHRESHOLD

#define DEFAULT_COMPRESSTHRESHOLD   0.5

Compression is used if percentage of moved vars is at most the threshold.

Definition at line 181 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ DEFAULT_SYMFIXNONBINARYVARS

#define DEFAULT_SYMFIXNONBINARYVARS   FALSE

Whether all non-binary variables shall be not affected by symmetries if OF is active?

Definition at line 182 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ DEFAULT_ONLYBINARYSYMMETRY

#define DEFAULT_ONLYBINARYSYMMETRY   TRUE

Is only symmetry on binary variables used?

Definition at line 183 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ DEFAULT_CONSSADDLP

#define DEFAULT_CONSSADDLP   TRUE

Should the symmetry breaking constraints be added to the LP?

Definition at line 186 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ DEFAULT_ADDSYMRESACKS

#define DEFAULT_ADDSYMRESACKS   FALSE

Add inequalities for symresacks for each generator?

Definition at line 187 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ DEFAULT_DETECTORBITOPES

#define DEFAULT_DETECTORBITOPES   TRUE

Should we check whether the components of the symmetry group can be handled by orbitopes?

Definition at line 188 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ DEFAULT_DETECTSUBGROUPS

#define DEFAULT_DETECTSUBGROUPS   TRUE

Should we try to detect orbitopes in subgroups of the symmetry group?

Definition at line 189 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ DEFAULT_ADDWEAKSBCS

#define DEFAULT_ADDWEAKSBCS   TRUE

Should we add weak SBCs for enclosing orbit of symmetric subgroups?

Definition at line 190 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ DEFAULT_ADDSTRONGSBCS

#define DEFAULT_ADDSTRONGSBCS   FALSE

Should we add strong SBCs for enclosing orbit of symmetric subgroups if orbitopes are not used?

Definition at line 191 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ DEFAULT_ADDCONSSTIMING

#define DEFAULT_ADDCONSSTIMING   2

timing of adding constraints (0 = before presolving, 1 = during presolving, 2 = after presolving)

Definition at line 192 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ DEFAULT_MAXNCONSSSUBGROUP

#define DEFAULT_MAXNCONSSSUBGROUP   500000

Maximum number of constraints up to which subgroup structures are detected

Definition at line 193 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ DEFAULT_USEDYNAMICPROP

#define DEFAULT_USEDYNAMICPROP   TRUE

whether dynamic propagation should be used for full orbitopes

Definition at line 194 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ DEFAULT_PREFERLESSROWS

#define DEFAULT_PREFERLESSROWS   TRUE

Shall orbitopes with less rows be preferred in detection?

Definition at line 195 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ DEFAULT_OFSYMCOMPTIMING

#define DEFAULT_OFSYMCOMPTIMING   2

timing of symmetry computation for orbital fixing (0 = before presolving, 1 = during presolving, 2 = at first call)

Definition at line 198 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ DEFAULT_PERFORMPRESOLVING

#define DEFAULT_PERFORMPRESOLVING   FALSE

Run orbital fixing during presolving?

Definition at line 199 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ DEFAULT_RECOMPUTERESTART

#define DEFAULT_RECOMPUTERESTART   0

Recompute symmetries after a restart has occurred? (0 = never)

Definition at line 200 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ DEFAULT_SSTTIEBREAKRULE

#define DEFAULT_SSTTIEBREAKRULE   1

index of tie break rule for selecting orbit for Schreier Sims constraints?

Definition at line 203 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ DEFAULT_SSTLEADERRULE

#define DEFAULT_SSTLEADERRULE   0

index of rule for selecting leader variables for Schreier Sims constraints?

Definition at line 204 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ DEFAULT_SSTLEADERVARTYPE

#define DEFAULT_SSTLEADERVARTYPE   14

bitset encoding which variable types can be leaders (1: binary; 2: integer; 4: impl. int; 8: continuous); if multiple types are allowed, take the one with most affected vars

Definition at line 205 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ DEFAULT_ADDCONFLICTCUTS

#define DEFAULT_ADDCONFLICTCUTS   TRUE

Should Schreier Sims constraints be added if we use a conflict based rule?

Definition at line 208 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ DEFAULT_SSTADDCUTS

#define DEFAULT_SSTADDCUTS   TRUE

Should Schreier Sims constraints be added?

Definition at line 209 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ DEFAULT_SSTMIXEDCOMPONENTS

#define DEFAULT_SSTMIXEDCOMPONENTS   TRUE

Should Schreier Sims constraints be added if a symmetry component contains variables of different types?

Definition at line 210 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ EVENTHDLR_SYMMETRY_NAME

#define EVENTHDLR_SYMMETRY_NAME   "symmetry"

Definition at line 213 of file prop_symmetry.c.

Referenced by SCIP_DECL_EVENTEXEC(), and SCIPincludePropSymmetry().

◆ EVENTHDLR_SYMMETRY_DESC

#define EVENTHDLR_SYMMETRY_DESC   "filter global variable fixing event handler for orbital fixing"

Definition at line 214 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ TABLE_NAME_ORBITALFIXING

#define TABLE_NAME_ORBITALFIXING   "orbitalfixing"

Definition at line 217 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ TABLE_DESC_ORBITALFIXING

#define TABLE_DESC_ORBITALFIXING   "orbital fixing statistics"

Definition at line 218 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ TABLE_POSITION_ORBITALFIXING

#define TABLE_POSITION_ORBITALFIXING   7001

the position of the statistics table

Definition at line 219 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ TABLE_EARLIEST_ORBITALFIXING

#define TABLE_EARLIEST_ORBITALFIXING   SCIP_STAGE_SOLVING

output of the statistics table is only printed from this stage onwards

Definition at line 220 of file prop_symmetry.c.

Referenced by SCIPincludePropSymmetry().

◆ MAXGENNUMERATOR

#define MAXGENNUMERATOR   64000000

determine maximal number of generators by dividing this number by the number of variables

Definition at line 224 of file prop_symmetry.c.

Referenced by determineSymmetry().

◆ SCIP_SPECIALVAL

#define SCIP_SPECIALVAL   1.12345678912345e+19

special floating point value for handling zeros in bound disjunctions

Definition at line 225 of file prop_symmetry.c.

Referenced by computeSymmetryGroup().

◆ COMPRESSNVARSLB

#define COMPRESSNVARSLB   25000

lower bound on the number of variables above which compression could be performed

Definition at line 226 of file prop_symmetry.c.

Referenced by setSymmetryData().

◆ ISSYMRETOPESACTIVE

#define ISSYMRETOPESACTIVE (   x)    (((unsigned) x & SYM_HANDLETYPE_SYMBREAK) != 0)

Definition at line 229 of file prop_symmetry.c.

Referenced by setSymmetryMethodEnabledValues().

◆ ISORBITALFIXINGACTIVE

#define ISORBITALFIXINGACTIVE (   x)    (((unsigned) x & SYM_HANDLETYPE_ORBITALFIXING) != 0)

Definition at line 230 of file prop_symmetry.c.

Referenced by freeSymmetryData(), and setSymmetryMethodEnabledValues().

◆ ISSSTACTIVE

#define ISSSTACTIVE (   x)    (((unsigned) x & SYM_HANDLETYPE_SST) != 0)

Definition at line 231 of file prop_symmetry.c.

Referenced by setSymmetryMethodEnabledValues().

◆ ISSSTBINACTIVE

#define ISSSTBINACTIVE (   x)    (((unsigned) x & SCIP_SSTTYPE_BINARY) != 0)

Definition at line 233 of file prop_symmetry.c.

Referenced by addSSTConss(), and addSymresackConss().

◆ ISSSTINTACTIVE

#define ISSSTINTACTIVE (   x)    (((unsigned) x & SCIP_SSTTYPE_INTEGER) != 0)

Definition at line 234 of file prop_symmetry.c.

Referenced by addSSTConss(), addSymresackConss(), and determineSymmetry().

◆ ISSSTIMPLINTACTIVE

#define ISSSTIMPLINTACTIVE (   x)    (((unsigned) x & SCIP_SSTTYPE_IMPLINT) != 0)

Definition at line 235 of file prop_symmetry.c.

Referenced by addSSTConss(), addSymresackConss(), and determineSymmetry().

◆ ISSSTCONTACTIVE

#define ISSSTCONTACTIVE (   x)    (((unsigned) x & SCIP_SSTTYPE_CONTINUOUS) != 0)

Definition at line 236 of file prop_symmetry.c.

Referenced by addSSTConss(), addSymresackConss(), and determineSymmetry().

Typedef Documentation

◆ SCIP_NODEDATA

typedef struct SCIP_NodeData SCIP_NODEDATA

Definition at line 363 of file prop_symmetry.c.

◆ SYM_SORTRHSTYPE

Definition at line 559 of file prop_symmetry.c.

◆ SYM_SORTGRAPHCOMPVARS

Definition at line 567 of file prop_symmetry.c.

Function Documentation

◆ SCIP_DECL_EVENTEXEC()

static SCIP_DECL_EVENTEXEC ( eventExecSymmetry  )
static

exec the event handler for handling global variable bound changes (necessary for orbital fixing)

Global variable fixings during the solving process might arise because parts of the tree are pruned or if certain preprocessing steps are performed that do not correspond to strict setting algorithms. Since these fixings might be caused by or be in conflict with orbital fixing, they can be in conflict with the symmetry handling decisions of orbital fixing in the part of the tree that is not pruned. Thus, we have to take global fixings into account when filtering out symmetries.

Definition at line 379 of file prop_symmetry.c.

References EVENTHDLR_SYMMETRY_NAME, NULL, SCIP_DECL_TABLEOUTPUT(), SCIP_EVENTTYPE_GLBCHANGED, SCIP_EVENTTYPE_GUBCHANGED, SCIP_INVALIDDATA, SCIP_OKAY, SCIP_VARTYPE_BINARY, SCIPABORT, SCIPdebugMsg, SCIPerrorMessage, SCIPeventGetNewbound(), SCIPeventGetOldbound(), SCIPeventGetType(), SCIPeventGetVar(), SCIPeventhdlrGetName(), SCIPhashmapExists(), SCIPhashmapGetImageInt(), SCIPisEQ(), SCIPvarGetName(), SCIPvarGetType(), and TRUE.

◆ SCIP_DECL_TABLEOUTPUT()

static SCIP_DECL_TABLEOUTPUT ( tableOutputOrbitalfixing  )
static

output method of orbital fixing propagator statistics table to output file stream 'file'

Definition at line 455 of file prop_symmetry.c.

References NULL, SCIP_DECL_TABLEFREE(), SCIP_OKAY, SCIP_VERBLEVEL_MINIMAL, SCIPtableGetData(), and SCIPverbMessage().

Referenced by SCIP_DECL_EVENTEXEC().

◆ SCIP_DECL_TABLEFREE()

static SCIP_DECL_TABLEFREE ( tableFreeOrbitalfixing  )
static

destructor of statistics table to free user data (called when SCIP is exiting)

Definition at line 479 of file prop_symmetry.c.

References NULL, SCIP_DECL_HASHGETKEY(), SCIP_OKAY, SCIPfreeBlockMemory, and SCIPtableGetData().

Referenced by SCIP_DECL_TABLEOUTPUT().

◆ SCIP_DECL_HASHGETKEY()

static SCIP_DECL_HASHGETKEY ( SYMhashGetKeyVartype  )
static

gets the key of the given element

Definition at line 498 of file prop_symmetry.c.

References SCIP_DECL_HASHKEYEQ().

Referenced by SCIP_DECL_TABLEFREE().

◆ SCIP_DECL_HASHKEYEQ()

static SCIP_DECL_HASHKEYEQ ( SYMhashKeyEQVartype  )
static

returns TRUE iff both keys are equal

Compare the types of two variables according to objective, lower and upper bound, variable type, and column sparsity.

Definition at line 508 of file prop_symmetry.c.

References FALSE, SYM_Vartype::lb, SYM_Vartype::nconss, SYM_Vartype::obj, SCIP_DECL_HASHKEYVAL(), SCIPisEQ(), TRUE, SYM_Vartype::type, and SYM_Vartype::ub.

Referenced by SCIP_DECL_HASHGETKEY().

◆ SCIP_DECL_HASHKEYVAL()

static SCIP_DECL_HASHKEYVAL ( SYMhashKeyValVartype  )
static

returns the hash value of the key

Definition at line 543 of file prop_symmetry.c.

References SYM_Vartype::lb, SYM_Vartype::nconss, SYM_Vartype::obj, SCIPhashFour, SCIPrealHashCode(), and SYM_Vartype::ub.

Referenced by SCIP_DECL_HASHKEYEQ().

◆ SCIP_DECL_SORTINDCOMP() [1/3]

static SCIP_DECL_SORTINDCOMP ( SYMsortRhsTypes  )
static

sorts rhs types - first by sense, then by value

Due to numerical issues, we first sort by sense, then by value.

result: < 0: ind1 comes before (is better than) ind2 = 0: both indices have the same value

0: ind2 comes after (is worse than) ind2

Definition at line 579 of file prop_symmetry.c.

References SCIP_Real, SYM_Sortrhstype::senses, and SYM_Sortrhstype::vals.

Referenced by SCIP_DECL_SORTINDCOMP().

◆ SCIP_DECL_SORTINDCOMP() [2/3]

static SCIP_DECL_SORTINDCOMP ( SYMsortMatCoef  )
static

sorts matrix coefficients

result: < 0: ind1 comes before (is better than) ind2 = 0: both indices have the same value

0: ind2 comes after (is worse than) ind2

Definition at line 613 of file prop_symmetry.c.

References SCIP_DECL_SORTINDCOMP(), and SCIP_Real.

◆ SCIP_DECL_SORTINDCOMP() [3/3]

static SCIP_DECL_SORTINDCOMP ( SYMsortGraphCompVars  )
static

sorts variable indices according to their corresponding component in the graph

Variables are sorted first by the color of their component and then by the component index.

result: < 0: ind1 comes before (is better than) ind2 = 0: both indices have the same value

0: ind2 comes after (is worse than) ind2

Definition at line 640 of file prop_symmetry.c.

References checkSymmetryDataFree(), SYM_Sortgraphcompvars::colors, SYM_Sortgraphcompvars::components, and SCIP_Bool.

◆ checkSymmetryDataFree()

static SCIP_Bool checkSymmetryDataFree ( SCIP_PROPDATA propdata)
static

checks that symmetry data is all freed

Parameters
propdatapropagator data

Definition at line 668 of file prop_symmetry.c.

References FALSE, isLeadervartypeCompatible(), NULL, SCIP_Bool, and TRUE.

Referenced by determineSymmetry(), freeSymmetryData(), and SCIP_DECL_SORTINDCOMP().

◆ isLeadervartypeCompatible()

static SCIP_Bool isLeadervartypeCompatible ( SCIP_VAR var,
int  leadervartype 
)
static

checks whether a variable has a type compatible with the leader vartype

Parameters
varvariable to check
leadervartypebit set encoding possible leader variable types

Definition at line 717 of file prop_symmetry.c.

References NULL, SCIP_Bool, SCIP_VARTYPE_BINARY, SCIP_VARTYPE_IMPLINT, SCIP_VARTYPE_INTEGER, SCIPvarGetType(), and setSymmetryMethodEnabledValues().

Referenced by checkSymmetryDataFree(), and determineSymmetry().

◆ setSymmetryMethodEnabledValues()

static SCIP_RETCODE setSymmetryMethodEnabledValues ( SCIP_PROPDATA propdata)
static

sets in propdata which symmetry handling methods are active

Parameters
propdatapropagator data

Definition at line 746 of file prop_symmetry.c.

References FALSE, freeSymmetryData(), ISORBITALFIXINGACTIVE, ISSSTACTIVE, ISSYMRETOPESACTIVE, NULL, SCIP_OKAY, and TRUE.

Referenced by isLeadervartypeCompatible(), SCIP_DECL_PROPEXEC(), and SCIP_DECL_PROPINITPRE().

◆ freeSymmetryData()

◆ SymmetryFixVar()

static SCIP_Bool SymmetryFixVar ( SYM_SPEC  fixedtype,
SCIP_VAR var 
)
static

determines whether variable should be fixed by permutations

Parameters
fixedtypebitset of variable types that should be fixed
varvariable to be considered

Definition at line 1004 of file prop_symmetry.c.

References FALSE, getActiveVariables(), SCIP_VARTYPE_BINARY, SCIP_VARTYPE_CONTINUOUS, SCIP_VARTYPE_IMPLINT, SCIP_VARTYPE_INTEGER, SCIPvarGetType(), SYM_SPEC_BINARY, SYM_SPEC_INTEGER, SYM_SPEC_REAL, and TRUE.

Referenced by checkSymmetriesAreSymmetries(), computeSymmetryGroup(), and freeSymmetryData().

◆ getActiveVariables()

static SCIP_RETCODE getActiveVariables ( SCIP scip,
SCIP_VAR ***  vars,
SCIP_Real **  scalars,
int *  nvars,
SCIP_Real constant,
SCIP_Bool  transformed 
)
static

Transforms given variables, scalars, and constant to the corresponding active variables, scalars, and constant.

Note
constant needs to be initialized!
Parameters
scipSCIP data structure
varspointer to vars array to get active variables for
scalarspointer to scalars a_1, ..., a_n in linear sum a_1*x_1 + ... + a_n*x_n + c
nvarspointer to number of variables and values in vars and vals array
constantpointer to constant c in linear sum a_1*x_1 + ... + a_n*x_n + c
transformedtransformed constraint?

Definition at line 1025 of file prop_symmetry.c.

References collectCoefficients(), NULL, scalars, SCIP_CALL, SCIP_OKAY, SCIPgetProbvarLinearSum(), SCIPreallocBufferArray, SCIPvarGetOrigvarSum(), and TRUE.

Referenced by collectCoefficients(), and SymmetryFixVar().

◆ collectCoefficients()

static SCIP_RETCODE collectCoefficients ( SCIP scip,
SCIP_Bool  doubleequations,
SCIP_VAR **  linvars,
SCIP_Real linvals,
int  nlinvars,
SCIP_Real  lhs,
SCIP_Real  rhs,
SCIP_Bool  istransformed,
SYM_RHSSENSE  rhssense,
SYM_MATRIXDATA matrixdata,
int *  nconssforvar 
)
static

fills in matrix elements into coefficient arrays

Parameters
scipSCIP data structure
doubleequationsDouble equations to positive/negative version?
linvarsarray of linear variables
linvalsarray of linear coefficients values (or NULL if all linear coefficient values are 1)
nlinvarsnumber of linear variables
lhsleft hand side
rhsright hand side
istransformedwhether the constraint is transformed
rhssenseidentifier of constraint type
matrixdatamatrix data to be filled in
nconssforvarpointer to array to store for each var the number of conss

Definition at line 1071 of file prop_symmetry.c.

References checkSymmetriesAreSymmetries(), FALSE, getActiveVariables(), SYM_Matrixdata::matcoef, SYM_Matrixdata::matidx, SYM_Matrixdata::matrhsidx, SYM_Matrixdata::matvaridx, SYM_Matrixdata::nmatcoef, SYM_Matrixdata::nmaxmatcoef, SYM_Matrixdata::nrhscoef, NULL, SYM_Matrixdata::rhscoef, SYM_Matrixdata::rhsidx, SYM_Matrixdata::rhssense, SCIP_Bool, SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIPallocBufferArray, SCIPcalcMemGrowSize(), SCIPdebugMsg, SCIPduplicateBufferArray, SCIPfreeBufferArray, SCIPgetNVars(), SCIPisEQ(), SCIPisInfinity(), SCIPisPositive(), SCIPreallocBlockMemoryArray, SCIPvarGetProbindex(), SYM_SENSE_BOUNDIS_TYPE_2, SYM_SENSE_EQUATION, SYM_SENSE_INEQUALITY, SYM_SENSE_XOR, and TRUE.

Referenced by computeSymmetryGroup(), and getActiveVariables().

◆ checkSymmetriesAreSymmetries()

static SCIP_RETCODE checkSymmetriesAreSymmetries ( SCIP scip,
SYM_SPEC  fixedtype,
SYM_MATRIXDATA matrixdata,
int  nperms,
int **  perms 
)
static

checks whether given permutations form a symmetry of a MIP

We need the matrix and rhs in the original order in order to speed up the comparison process. The matrix is needed in the right order to easily check rows. The rhs is used because of cache effects.

Parameters
scipSCIP data structure
fixedtypevariable types that must be fixed by symmetries
matrixdatamatrix data
npermsnumber of permutations
permspermutations

Definition at line 1298 of file prop_symmetry.c.

References FALSE, getNSymhandableConss(), SYM_Matrixdata::matcoef, SYM_Matrixdata::matrhsidx, SYM_Matrixdata::matvaridx, SYM_Matrixdata::nmatcoef, SYM_Matrixdata::npermvars, SYM_Matrixdata::nrhscoef, NULL, SYM_Matrixdata::permvars, SYM_Matrixdata::rhscoef, SYM_Matrixdata::rhssense, SCIP_Bool, SCIP_CALL, SCIP_ERROR, SCIP_OKAY, SCIP_Real, SCIPallocBlockMemoryArray, SCIPallocBufferArray, SCIPblkmem(), SCIPcompareExpr(), SCIPconshdlrGetConss(), SCIPconshdlrGetNConss(), SCIPconsIsChecked(), SCIPconsIsDynamic(), SCIPconsIsEnforced(), SCIPconsIsInitial(), SCIPconsIsLocal(), SCIPconsIsModifiable(), SCIPconsIsPropagated(), SCIPconsIsRemovable(), SCIPconsIsSeparated(), SCIPconsIsStickingAtNode(), SCIPdebugMsg, SCIPerrorMessage, SCIPfindConshdlr(), SCIPfreeBlockMemoryArray, SCIPfreeBufferArray, SCIPgetConsCopy(), SCIPgetConsNVars(), SCIPgetConsVars(), SCIPgetExprNonlinear(), SCIPgetLhsNonlinear(), SCIPgetRhsNonlinear(), SCIPhashmapCreate(), SCIPhashmapFree(), SCIPhashmapInsert(), SCIPhashmapRemoveAll(), SCIPisEQ(), SCIPisZero(), SCIPreleaseCons(), SCIPreleaseExpr(), SCIPsimplifyExpr(), SCIPvarGetProbindex(), SymmetryFixVar(), and TRUE.

Referenced by collectCoefficients(), and computeSymmetryGroup().

◆ getNSymhandableConss()

static int getNSymhandableConss ( SCIP scip,
SCIP_CONSHDLR conshdlr_nonlinear 
)
static

returns the number of active constraints that can be handled by symmetry

Parameters
scipSCIP instance
conshdlr_nonlinearnonlinear constraint handler, if included

Definition at line 1556 of file prop_symmetry.c.

References hasNonlinearConstraints(), NULL, SCIP_Bool, SCIPconshdlrGetNActiveConss(), and SCIPfindConshdlr().

Referenced by checkSymmetriesAreSymmetries(), computeSymmetryGroup(), and determineSymmetry().

◆ hasNonlinearConstraints()

static SCIP_Bool hasNonlinearConstraints ( SCIP_PROPDATA propdata)
static

returns whether there are any active nonlinear constraints

Parameters
propdatapropagator data

Definition at line 1594 of file prop_symmetry.c.

References NULL, SCIPconshdlrGetNActiveConss(), and setSymmetryData().

Referenced by getNSymhandableConss(), propagateOrbitalFixing(), SCIP_DECL_PROPEXITPRE(), SCIP_DECL_PROPINITPRE(), SCIP_DECL_PROPPRESOL(), and tryAddSymmetryHandlingConss().

◆ setSymmetryData()

static SCIP_RETCODE setSymmetryData ( SCIP scip,
SCIP_VAR **  vars,
int  nvars,
int  nbinvars,
SCIP_VAR ***  permvars,
int *  npermvars,
int *  nbinpermvars,
int **  perms,
int  nperms,
int *  nmovedvars,
SCIP_Bool binvaraffected,
SCIP_Bool  usecompression,
SCIP_Real  compressthreshold,
SCIP_Bool compressed 
)
static

set symmetry data

Parameters
scipSCIP pointer
varsvars present at time of symmetry computation
nvarsnumber of vars present at time of symmetry computation
nbinvarsnumber of binary vars present at time of symmetry computation
permvarspointer to permvars array
npermvarspointer to store number of permvars
nbinpermvarspointer to store number of binary permvars
permspermutations matrix (nperms x nvars)
npermsnumber of permutations
nmovedvarspointer to store number of vars affected by symmetry (if usecompression) or NULL
binvaraffectedpointer to store whether a binary variable is affected by symmetry
usecompressionwhether symmetry data shall be compressed
compressthresholdif percentage of moved vars is at most threshold, compression is done
compressedpointer to store whether compression has been performed

Definition at line 1605 of file prop_symmetry.c.

References COMPRESSNVARSLB, computeSymmetryGroup(), FALSE, NULL, SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIP_VARTYPE_BINARY, SCIPallocBlockMemoryArray, SCIPallocBufferArray, SCIPfreeBlockMemoryArray, SCIPfreeBufferArray, SCIPgetNVars(), SCIPisGE(), SCIPisLE(), SCIPreallocBlockMemoryArray, SCIPvarGetType(), and TRUE.

Referenced by computeSymmetryGroup(), and hasNonlinearConstraints().

◆ computeSymmetryGroup()

static SCIP_RETCODE computeSymmetryGroup ( SCIP scip,
SCIP_Bool  doubleequations,
SCIP_Bool  compresssymmetries,
SCIP_Real  compressthreshold,
int  maxgenerators,
SYM_SPEC  fixedtype,
SCIP_Bool  local,
SCIP_Bool  checksymmetries,
SCIP_Bool  usecolumnsparsity,
SCIP_CONSHDLR conshdlr_nonlinear,
int *  npermvars,
int *  nbinpermvars,
SCIP_VAR ***  permvars,
int *  nperms,
int *  nmaxperms,
int ***  perms,
SCIP_Real log10groupsize,
int *  nmovedvars,
SCIP_Bool **  isnonlinvar,
SCIP_Bool binvaraffected,
SCIP_Bool compressed,
SCIP_Bool success 
)
static

computes symmetry group of a MIP

Parameters
scipSCIP pointer
doubleequationsDouble equations to positive/negative version?
compresssymmetriesShould non-affected variables be removed from permutation to save memory?
compressthresholdCompression is used if percentage of moved vars is at most the threshold.
maxgeneratorsmaximal number of generators constructed (= 0 if unlimited)
fixedtypevariable types that must be fixed by symmetries
localUse local variable bounds?
checksymmetriesShould all symmetries be checked after computation?
usecolumnsparsityShould the number of conss a variable is contained in be exploited in symmetry detection?
conshdlr_nonlinearNonlinear constraint handler, if included
npermvarspointer to store number of variables for permutations
nbinpermvarspointer to store number of binary variables for permutations
permvarspointer to store variables on which permutations act
npermspointer to store number of permutations
nmaxpermspointer to store maximal number of permutations (needed for freeing storage)
permspointer to store permutation generators as (nperms x npermvars) matrix
log10groupsizepointer to store log10 of size of group
nmovedvarspointer to store number of moved vars
isnonlinvarpointer to store which variables appear nonlinearly
binvaraffectedpointer to store wether a binary variable is affected by symmetry
compressedpointer to store whether compression has been performed
successpointer to store whether symmetry computation was successful

Definition at line 1736 of file prop_symmetry.c.

References checkSymmetriesAreSymmetries(), collectCoefficients(), SYM_Vartype::color, determineSymmetry(), FALSE, getNSymhandableConss(), SYM_Vartype::lb, SYM_Matrixdata::matcoef, SYM_Matrixdata::matcoefcolors, SYM_Matrixdata::matidx, SYM_Matrixdata::matrhsidx, SYM_Matrixdata::matvaridx, MAX, SYM_Vartype::nconss, SYM_Matrixdata::nmatcoef, SYM_Matrixdata::nmaxmatcoef, SYM_Matrixdata::npermvars, SYM_Matrixdata::nrhscoef, SYM_Sortrhstype::nrhscoef, NULL, SYM_Exprdata::nuniquecoefs, SYM_Exprdata::nuniqueconstants, SYM_Matrixdata::nuniquemat, SYM_Exprdata::nuniqueoperators, SYM_Matrixdata::nuniquerhs, SYM_Matrixdata::nuniquevars, SYM_Vartype::obj, SYM_Matrixdata::permvarcolors, SYM_Matrixdata::permvars, SYM_Matrixdata::rhscoef, SYM_Matrixdata::rhscoefcolors, SYM_Matrixdata::rhsidx, SYM_Matrixdata::rhssense, SCIP_Bool, SCIP_BOUNDTYPE_LOWER, SCIP_CALL, SCIP_ERROR, SCIP_EXPRITER_DFS, SCIP_EXPRITER_ENTEREXPR, SCIP_INVALID, SCIP_Longint, SCIP_OKAY, SCIP_Real, SCIP_SETPPCTYPE_COVERING, SCIP_SETPPCTYPE_PACKING, SCIP_SETPPCTYPE_PARTITIONING, SCIP_SPECIALVAL, SCIP_STAGE_INITPRESOLVE, SCIP_STAGE_SOLVING, SCIP_VERBLEVEL_HIGH, SCIPallocBlockMemoryArray, SCIPallocClearBlockMemoryArray, SCIPblkmem(), SCIPconsGetHdlr(), SCIPconsGetName(), SCIPconshdlrGetNActiveConss(), SCIPconshdlrGetName(), SCIPconsIsActive(), SCIPconsIsConflict(), SCIPconsIsTransformed(), SCIPcreateExpriter(), SCIPdebugMsg, SCIPduplicateBlockMemoryArray, SCIPerrorMessage, SCIPexprGetNChildren(), SCIPexpriterGetCurrent(), SCIPexpriterGetNext(), SCIPexpriterGetParentDFS(), SCIPexpriterGetStageDFS(), SCIPexpriterInit(), SCIPexpriterIsEnd(), SCIPexpriterSetStagesDFS(), SCIPfreeBlockMemoryArray, SCIPfreeBlockMemoryArrayNull, SCIPfreeExpriter(), SCIPgetBinvarsLinking(), SCIPgetBoundsBounddisjunction(), SCIPgetBoundtypesBounddisjunction(), SCIPgetCapacityKnapsack(), SCIPgetConss(), SCIPgetExprAuxVarNonlinear(), SCIPgetExprNonlinear(), SCIPgetIntVarXor(), SCIPgetLhsLinear(), SCIPgetLhsVarbound(), SCIPgetLinkvarLinking(), SCIPgetNActiveConss(), SCIPgetNBinVars(), SCIPgetNConss(), SCIPgetNFixedVars(), SCIPgetNVars(), SCIPgetNVarsAnd(), SCIPgetNVarsBounddisjunction(), SCIPgetNVarsKnapsack(), SCIPgetNVarsLinear(), SCIPgetNVarsLogicor(), SCIPgetNVarsOr(), SCIPgetNVarsSetppc(), SCIPgetNVarsXor(), SCIPgetResultantAnd(), SCIPgetResultantOr(), SCIPgetRhsLinear(), SCIPgetRhsVarbound(), SCIPgetRhsXor(), SCIPgetStage(), SCIPgetTypeSetppc(), SCIPgetValsLinear(), SCIPgetValsLinking(), SCIPgetVarExprVar(), SCIPgetVars(), SCIPgetVarsAnd(), SCIPgetVarsBounddisjunction(), SCIPgetVarsKnapsack(), SCIPgetVarsLinear(), SCIPgetVarsLogicor(), SCIPgetVarsOr(), SCIPgetVarsSetppc(), SCIPgetVarsXor(), SCIPgetVarVarbound(), SCIPgetVbdcoefVarbound(), SCIPgetVbdvarVarbound(), SCIPgetWeightsKnapsack(), SCIPhashsetCreate(), SCIPhashsetExists(), SCIPhashsetFree(), SCIPhashsetInsert(), SCIPhashtableCreate(), SCIPhashtableExists(), SCIPhashtableFree(), SCIPhashtableInsert(), SCIPhashtableRetrieve(), SCIPinfinity(), SCIPisEQ(), SCIPisExprSum(), SCIPisExprValue(), SCIPisExprVar(), SCIPisStopped(), SCIPisZero(), SCIPsort(), SCIPvarGetLbGlobal(), SCIPvarGetLbLocal(), SCIPvarGetName(), SCIPvarGetObj(), SCIPvarGetProbindex(), SCIPvarGetType(), SCIPvarGetUbGlobal(), SCIPvarGetUbLocal(), SCIPverbMessage(), SYM_Sortrhstype::senses, setSymmetryData(), SYM_SENSE_AND, SYM_SENSE_BOUNDIS_TYPE_1, SYM_SENSE_BOUNDIS_TYPE_2, SYM_SENSE_EQUATION, SYM_SENSE_INEQUALITY, SYM_SENSE_OR, SYM_SENSE_UNKOWN, SYM_SENSE_XOR, SYMcanComputeSymmetry(), SYMcomputeSymmetryGenerators(), SymmetryFixVar(), TRUE, SYM_Vartype::type, SYM_Vartype::ub, and SYM_Sortrhstype::vals.

Referenced by determineSymmetry(), and setSymmetryData().

◆ determineSymmetry()

static SCIP_RETCODE determineSymmetry ( SCIP scip,
SCIP_PROPDATA propdata,
SYM_SPEC  symspecrequire,
SYM_SPEC  symspecrequirefixed 
)
static

determines symmetry

Parameters
scipSCIP instance
propdatapropagator data
symspecrequiresymmetry specification for which we need to compute symmetries
symspecrequirefixedsymmetry specification of variables which must be fixed by symmetries

Definition at line 2551 of file prop_symmetry.c.

References checkSymmetryDataFree(), checkTwoCyclePermsAreOrbitope(), computeSymmetryGroup(), FALSE, freeSymmetryData(), getNSymhandableConss(), isLeadervartypeCompatible(), ISSSTCONTACTIVE, ISSSTIMPLINTACTIVE, ISSSTINTACTIVE, MAXGENNUMERATOR, NULL, SCIP_Bool, SCIP_CALL, SCIP_EVENTTYPE_GLBCHANGED, SCIP_EVENTTYPE_GUBCHANGED, SCIP_OKAY, SCIP_SSTTYPE_BINARY, SCIP_VARTYPE_BINARY, SCIP_VARTYPE_IMPLINT, SCIP_VARTYPE_INTEGER, SCIP_VERBLEVEL_HIGH, SCIPallocBlockMemoryArray, SCIPblkmem(), SCIPcaptureVar(), SCIPcatchVarEvent(), SCIPcomputeComponentsSym(), SCIPdetermineNVarsAffectedSym(), SCIPfreeBlockMemoryArray, SCIPfreeBlockMemoryArrayNull, SCIPgetNActiveBenders(), SCIPgetNActiveConss(), SCIPgetNActivePricers(), SCIPgetNBinVars(), SCIPgetNContVars(), SCIPgetNImplVars(), SCIPgetNIntVars(), SCIPgetNRuns(), SCIPgetNVars(), SCIPgetSolvingTime(), SCIPhashmapCreate(), SCIPhashmapInsertInt(), SCIPisReoptEnabled(), SCIPmarkDoNotMultaggrVar(), SCIPvarGetObj(), SCIPvarGetType(), SCIPvarIsBinary(), SCIPverbMessage(), SCIPwarningMessage(), SYM_SPEC_BINARY, SYM_SPEC_INTEGER, SYM_SPEC_REAL, SYMcanComputeSymmetry(), and TRUE.

Referenced by computeSymmetryGroup(), propagateOrbitalFixing(), SCIP_DECL_PROPEXITPRE(), SCIP_DECL_PROPINITPRE(), SCIP_DECL_PROPPRESOL(), and tryAddSymmetryHandlingConss().

◆ checkTwoCyclePermsAreOrbitope()

static SCIP_RETCODE checkTwoCyclePermsAreOrbitope ( SCIP scip,
SCIP_VAR **  permvars,
int  npermvars,
int **  perms,
int *  activeperms,
int  ntwocycles,
int  nactiveperms,
int **  orbitopevaridx,
int *  columnorder,
int *  nusedelems,
int *  nusedcols,
SCIP_Shortbool rowisbinary,
SCIP_Bool isorbitope,
SCIP_Shortbool activevars 
)
static

Checks whether given set of 2-cycle permutations forms an orbitope and if so, builds the variable index matrix.

If activevars == NULL, then the function assumes all permutations of the component are active and therefore all moved vars are considered.

We need to keep track of the number of generatored columns, because we might not be able to detect all orbitopes. For example (1,2), (2,3), (3,4), (3,5) defines the symmetric group on {1,2,3,4,5}, but the generators we expect in our construction need shape (1,2), (2,3), (3,4), (4,5).

Precondition
orbitopevaridx has to be an initialized 2D array of size ntwocycles x nperms
columnorder has to be an initialized array of size nperms
nusedelems has to be an initialized array of size npermvars
Parameters
scipSCIP instance
permvarsarray of all permutation variables
npermvarsnumber of permutation variables
permsarray of all permutations of the symmety group
activepermsindices of the relevant permutations in perms
ntwocyclesnumber of 2-cycles in the permutations
nactivepermsnumber of active permutations
orbitopevaridxpointer to store variable index matrix
columnorderpointer to store column order
nusedelemspointer to store how often each element was used
nusedcolspointer to store numer of columns used in orbitope (or NULL)
rowisbinarypointer to store which rows are binary (or NULL)
isorbitopebuffer to store result
activevarsbitset to store whether a variable is active (or NULL)

Definition at line 3047 of file prop_symmetry.c.

References chooseOrderOfGenerators(), FALSE, NULL, SCIP_Bool, SCIP_CALL, SCIP_OKAY, SCIPallocClearBufferArray, SCIPextendSubOrbitope(), SCIPfreeBufferArray, SCIPvarIsBinary(), and TRUE.

Referenced by addOrbitopeSubgroup(), detectOrbitopes(), and determineSymmetry().

◆ chooseOrderOfGenerators()

static SCIP_RETCODE chooseOrderOfGenerators ( SCIP scip,
SCIP_PROPDATA propdata,
int  compidx,
int **  genorder,
int *  ntwocycleperms 
)
static

choose an order in which the generators should be added for subgroup detection

Parameters
scipSCIP instance
propdatapointer to data of symmetry propagator
compidxindex of component
genorder(initialized) buffer to store the resulting order of generator
ntwocyclepermspointer to store the number of 2-cycle permutations in component compidx

Definition at line 3232 of file prop_symmetry.c.

References buildSubgroupGraph(), SYM_Sortgraphcompvars::components, FALSE, NULL, SCIP_CALL, SCIP_OKAY, SCIPallocBufferArray, SCIPfreeBufferArray, SCIPisInvolutionPerm(), and SCIPsortIntInt().

Referenced by checkTwoCyclePermsAreOrbitope(), and detectAndHandleSubgroups().

◆ buildSubgroupGraph()

static SCIP_RETCODE buildSubgroupGraph ( SCIP scip,
SCIP_PROPDATA propdata,
int *  genorder,
int  ntwocycleperms,
int  compidx,
int **  graphcomponents,
int **  graphcompbegins,
int **  compcolorbegins,
int *  ngraphcomponents,
int *  ncompcolors,
int **  usedperms,
int *  nusedperms,
int  usedpermssize,
SCIP_Shortbool permused 
)
static

builds the graph for symmetric subgroup detection from the given permutation of generators

After execution, graphcomponents contains all permvars sorted by their color and component, graphcompbegins points to the indices where new components in graphcomponents start and compcolorbegins points to the indices where new colors in graphcompbegins start.

Parameters
scipSCIP instance
propdatapointer to data of symmetry propagator
genorderorder in which the generators should be considered
ntwocyclepermsnumber of 2-cycle permutations in this component
compidxindex of the component
graphcomponentsbuffer to store the components of the graph (ordered var indices)
graphcompbeginsbuffer to store the indices of each new graph component
compcolorbeginsbuffer to store at which indices a new color begins
ngraphcomponentspointer to store the number of graph components
ncompcolorspointer to store the number of different colors
usedpermsbuffer to store the indices of permutations that were used
nusedpermspointer to store the number of used permutations in the graph
usedpermssizeinitial size of usedperms
permusedinitialized buffer to store which permutations have been used (identified by index in component)

Definition at line 3310 of file prop_symmetry.c.

References addOrbitopeSubgroup(), SYM_Sortgraphcompvars::colors, SYM_Sortgraphcompvars::components, FALSE, NULL, SCIP_CALL, SCIP_OKAY, SCIPallocBlockMemoryArray, SCIPallocBufferArray, SCIPcalcMemGrowSize(), SCIPcreateDisjointset(), SCIPdisjointsetFind(), SCIPdisjointsetGetComponentCount(), SCIPdisjointsetUnion(), SCIPfreeBufferArray, SCIPfreeDisjointset(), SCIPreallocBufferArray, SCIPsort(), and TRUE.

Referenced by chooseOrderOfGenerators(), and detectAndHandleSubgroups().

◆ addOrbitopeSubgroup()

static SCIP_RETCODE addOrbitopeSubgroup ( SCIP scip,
SCIP_PROPDATA propdata,
int *  usedperms,
int  nusedperms,
int *  compcolorbegins,
int *  graphcompbegins,
int *  graphcomponents,
int  graphcoloridx,
int  nrows,
int  ncols,
int *  firstvaridx,
int *  compidxfirstrow,
int **  lexorder,
int *  nvarslexorder,
int *  maxnvarslexorder,
SCIP_Bool  mayinteract,
SCIP_Bool success 
)
static

adds an orbitope constraint for a suitable color of the subgroup graph

Parameters
scipSCIP instance
propdatapointer to data of symmetry propagator
usedpermsarray of the permutations that build the orbitope
nusedpermsnumber of permutations in usedperms
compcolorbeginsarray indicating where a new graphcolor begins
graphcompbeginsarray indicating where a new graphcomponent begins
graphcomponentsarray of all variable indices sorted by color and comp
graphcoloridxindex of the graph color
nrowsnumber of rows in the orbitope
ncolsnumber of columns in the orbitope
firstvaridxbuffer to store the index of the largest variable (or NULL)
compidxfirstrowbuffer to store the comp index for the first row (or NULL)
lexorderpointer to array storing lexicographic order defined by sub orbitopes
nvarslexordernumber of variables in lexicographic order
maxnvarslexordermaximum number of variables in lexicographic order
mayinteractwhether orbitope's symmetries might interact with other symmetries
successwhether the orbitpe could be added

Definition at line 3577 of file prop_symmetry.c.

References addStrongSBCsSubgroup(), checkTwoCyclePermsAreOrbitope(), FALSE, NULL, SCIP_Bool, SCIP_CALL, SCIP_MAXSTRLEN, SCIP_OKAY, SCIP_ORBITOPETYPE_FULL, SCIP_Shortbool, SCIPaddCons(), SCIPallocBufferArray, SCIPallocClearBufferArray, SCIPcreateConsOrbitope(), SCIPfreeBufferArray, SCIPgenerateOrbitopeVarsMatrix(), SCIPsnprintf(), SCIPvarIsBinary(), and TRUE.

Referenced by buildSubgroupGraph(), and detectAndHandleSubgroups().

◆ addStrongSBCsSubgroup()

static SCIP_RETCODE addStrongSBCsSubgroup ( SCIP scip,
SCIP_PROPDATA propdata,
int *  graphcompbegins,
int *  graphcomponents,
int  graphcompidx,
SCIP_Bool  storelexorder,
int **  lexorder,
int *  nvarsorder,
int *  maxnvarsorder 
)
static

adds strong SBCs for a suitable color of the subgroup graph

Parameters
scipSCIP instance
propdatapointer to data of symmetry propagator
graphcompbeginsarray indicating where a new graphcomponent begins
graphcomponentsarray of all variable indices sorted by color and comp
graphcompidxindex of the graph component
storelexorderwhether the lexicographic order induced by the orbitope shall be stored
lexorderpointer to array storing lexicographic order defined by sub orbitopes
nvarsordernumber of variables in lexicographic order
maxnvarsordermaximum number of variables in lexicographic order

Definition at line 3796 of file prop_symmetry.c.

References addWeakSBCsSubgroup(), FALSE, NULL, SCIP_CALL, SCIP_MAXSTRLEN, SCIP_OKAY, SCIP_Real, SCIPaddCons(), SCIPallocBlockMemoryArray, SCIPcalcMemGrowSize(), SCIPcreateConsLinear(), SCIPinfinity(), SCIPinfoMessage(), SCIPprintCons(), SCIPreallocBlockMemoryArray, SCIPsnprintf(), SCIPvarGetName(), and TRUE.

Referenced by addOrbitopeSubgroup(), and detectAndHandleSubgroups().

◆ addWeakSBCsSubgroup()

static SCIP_RETCODE addWeakSBCsSubgroup ( SCIP scip,
SCIP_PROPDATA propdata,
int *  compcolorbegins,
int *  graphcompbegins,
int *  graphcomponents,
int  ncompcolors,
int *  chosencomppercolor,
int *  firstvaridxpercolor,
int  symgrpcompidx,
int *  naddedconss,
SCIP_Bool  storelexorder,
int **  lexorder,
int *  nvarsorder,
int *  maxnvarsorder 
)
static

adds weak SBCs for a suitable color of the subgroup graph

Parameters
scipSCIP instance
propdatapointer to data of symmetry propagator
compcolorbeginsarray indicating where a new graphcolor begins
graphcompbeginsarray indicating where a new graphcomponent begins
graphcomponentsarray of all variable indices sorted by color and comp
ncompcolorsnumber of colors in the graph
chosencomppercolorarray indicating which comp was handled per color
firstvaridxpercolorarray indicating the largest variable per color
symgrpcompidxindex of the component of the symmetry group
naddedconssbuffer to store the number of added constraints
storelexorderwhether the lexicographic order induced by the orbitope shall be stored
lexorderpointer to array storing lexicographic order defined by sub orbitopes
nvarsordernumber of variables in lexicographic order
maxnvarsordermaximum number of variables in lexicographic order

Definition at line 3890 of file prop_symmetry.c.

References adaptSymmetryDataSST(), FALSE, NULL, SCIP_CALL, SCIP_MAXSTRLEN, SCIP_OKAY, SCIP_Real, SCIP_Shortbool, SCIPaddCons(), SCIPallocBlockMemoryArray, SCIPallocBufferArray, SCIPallocCleanBufferArray, SCIPallocClearBufferArray, SCIPblkmem(), SCIPcalcMemGrowSize(), SCIPcomputeOrbitVar(), SCIPcreateConsLinear(), SCIPdebugMsg, SCIPfreeBufferArray, SCIPfreeCleanBufferArray, SCIPhashmapCreate(), SCIPhashmapExists(), SCIPhashmapFree(), SCIPhashmapInsertInt(), SCIPinfinity(), SCIPinfoMessage(), SCIPprintCons(), SCIPreallocBlockMemoryArray, SCIPsnprintf(), SCIPvarGetName(), and TRUE.

Referenced by addStrongSBCsSubgroup(), and detectAndHandleSubgroups().

◆ adaptSymmetryDataSST()

static SCIP_RETCODE adaptSymmetryDataSST ( SCIP scip,
int **  origperms,
int **  modifiedperms,
int  nperms,
SCIP_VAR **  origpermvars,
SCIP_VAR **  modifiedpermvars,
int  npermvars,
int *  leaders,
int  nleaders 
)
static

temporarily adapt symmetry data to new variable order given by Schreier Sims

Parameters
scipSCIP instance
origpermspermutation matrix w.r.t. original variable ordering
modifiedpermsmemory for permutation matrix w.r.t. new variable ordering
npermsnumber of permutations
origpermvarsarray of permutation vars w.r.t. original variable ordering
modifiedpermvarsmemory for array of permutation vars w.r.t. new variable ordering
npermvarslength or modifiedpermvars array
leadersleaders of Schreier Sims constraints
nleadersnumber of leaders

Definition at line 4135 of file prop_symmetry.c.

References getNOrbitopesInComp(), NULL, SCIP_CALL, SCIP_OKAY, SCIPallocBufferArray, and SCIPfreeBufferArray.

Referenced by addSymresackConss(), addWeakSBCsSubgroup(), and detectAndHandleSubgroups().

◆ getNOrbitopesInComp()

static int getNOrbitopesInComp ( SCIP_VAR **  permvars,
int *  graphcomponents,
int *  graphcompbegins,
int *  compcolorbegins,
int  ncompcolors,
int  symcompsize 
)
static
Parameters
permvarsarray of variables affected by symmetry
graphcomponentsarray of graph components
graphcompbeginsarray indicating starting position of graph components
compcolorbeginsarray indicating starting positions of potential orbitopes
ncompcolorsnumber of components encoded in compcolorbegins
symcompsizesize of symmetry component for that we detect suborbitopes

Definition at line 4217 of file prop_symmetry.c.

References detectAndHandleSubgroups(), FALSE, NULL, SCIP_Bool, SCIP_Real, SCIPvarIsBinary(), and TRUE.

Referenced by adaptSymmetryDataSST(), and detectAndHandleSubgroups().

◆ detectAndHandleSubgroups()

◆ SCIPsortOrbitope()

static SCIP_RETCODE SCIPsortOrbitope ( SCIP scip,
int **  orbitopevaridx,
SCIP_VAR ***  vars,
int  nrows,
int  ncols 
)
static

sorts orbitope vars matrix such that rows are sorted increasingly w.r.t. minimum variable index in row; columns are sorted such that first row is sorted increasingly w.r.t. variable indices

Parameters
scipSCIP instance
orbitopevaridxvariable index matrix of orbitope
varsvariable matrix of orbitope
nrowsnumber of binary rows of orbitope
ncolsnumber of columns of orbitope

Definition at line 4821 of file prop_symmetry.c.

References detectOrbitopes(), MAX, NULL, SCIP_CALL, SCIP_OKAY, SCIPallocBufferArray, SCIPfreeBufferArray, SCIPsortIntIntPtr(), and SCIPsortIntPtr().

Referenced by detectAndHandleSubgroups(), and detectOrbitopes().

◆ detectOrbitopes()

static SCIP_RETCODE detectOrbitopes ( SCIP scip,
SCIP_PROPDATA propdata,
int *  components,
int *  componentbegins,
int  ncomponents 
)
static

checks whether components of the symmetry group can be completely handled by orbitopes

Parameters
scipSCIP instance
propdatapointer to data of symmetry propagator
componentsarray containing components of symmetry group
componentbeginsarray containing begin positions of components in components array
ncomponentsnumber of components

Definition at line 4903 of file prop_symmetry.c.

References checkTwoCyclePermsAreOrbitope(), SYM_Sortgraphcompvars::components, FALSE, NULL, SCIP_Bool, SCIP_CALL, SCIP_MAXSTRLEN, SCIP_OKAY, SCIP_ORBITOPETYPE_FULL, SCIP_Shortbool, SCIPaddCons(), SCIPallocBufferArray, SCIPallocClearBufferArray, SCIPcreateConsOrbitope(), SCIPdebugMsg, SCIPfreeBufferArray, SCIPgenerateOrbitopeVarsMatrix(), SCIPisInvolutionPerm(), SCIPsnprintf(), SCIPsortOrbitope(), SYM_HANDLETYPE_SYMBREAK, TRUE, and updateSymInfoConflictGraphSST().

Referenced by SCIPsortOrbitope(), and tryAddSymmetryHandlingConss().

◆ updateSymInfoConflictGraphSST()

static SCIP_RETCODE updateSymInfoConflictGraphSST ( SCIP scip,
SCIP_DIGRAPH conflictgraph,
SCIP_VAR **  graphvars,
int  ngraphvars,
SCIP_VAR **  permvars,
int  npermvars,
SCIP_Bool  onlypermvars,
SCIP_HASHMAP varmap,
int *  orbits,
int *  orbitbegins,
int  norbits 
)
static

update symmetry information of conflict graph

Parameters
scipSCIP instance
conflictgraphconflict graph
graphvarsvariables encoded in conflict graph (either all vars or permvars)
ngraphvarsnumber of nodes/vars in conflict graph
permvarsvariables considered in permutations
npermvarsnumber of permvars
onlypermvarswhether conflict graph contains only permvars
varmapmap from graphvar to node label in conflict graph (or NULL if onlypermvars == TRUE)
orbitsarray of non-trivial orbits
orbitbeginsarray containing begin positions of new orbits in orbits array
norbitsnumber of non-trivial orbits

Definition at line 5108 of file prop_symmetry.c.

References createConflictGraphSST(), nodedata, NULL, SCIP_CALL, SCIP_OKAY, SCIPallocBlockMemory, SCIPdigraphGetNodeData(), SCIPdigraphGetNSuccessors(), SCIPdigraphGetSuccessors(), SCIPdigraphSetNodeData(), SCIPhashmapExists(), SCIPhashmapGetImageInt(), and TRUE.

Referenced by addSSTConss(), and detectOrbitopes().

◆ createConflictGraphSST()

static SCIP_RETCODE createConflictGraphSST ( SCIP scip,
SCIP_DIGRAPH **  conflictgraph,
SCIP_VAR **  graphvars,
int  ngraphvars,
SCIP_Bool  onlypermvars,
SCIP_HASHMAP permvarmap,
SCIP_Bool success 
)
static

create conflict graph either for symmetric or for all variables

This routine just creates the graph, but does not add (symmetry) information to its nodes. This has to be done separately by the routine updateSymInfoConflictGraphSST().

Parameters
scipSCIP instance
conflictgraphpointer to store conflict graph
graphvarsvariables encoded in conflict graph
ngraphvarsnumber of vars encoded in conflict graph
onlypermvarswhether conflict graph contains only permvars
permvarmapmap of variables to indices in permvars array (or NULL)
successpointer to store whether conflict graph could be created successfully

Definition at line 5253 of file prop_symmetry.c.

References FALSE, freeConflictGraphSST(), NULL, SCIP_CALL, SCIP_OKAY, SCIP_SETPPCTYPE_COVERING, SCIPconsGetName(), SCIPconshdlrGetConss(), SCIPconshdlrGetNConss(), SCIPcreateDigraph(), SCIPdebugMsg, SCIPdigraphAddArcSafe(), SCIPfindConshdlr(), SCIPgetNVarsSetppc(), SCIPgetTypeSetppc(), SCIPgetVarsSetppc(), SCIPhashmapGetImageInt(), SCIPvarGetProbindex(), and TRUE.

Referenced by addSSTConss(), and updateSymInfoConflictGraphSST().

◆ freeConflictGraphSST()

static SCIP_RETCODE freeConflictGraphSST ( SCIP scip,
SCIP_DIGRAPH **  conflictgraph,
int  nnodes 
)
static

frees conflict graph

Parameters
scipSCIP instance
conflictgraphconflict graph
nnodesnumber of nodes in conflict graph

Definition at line 5377 of file prop_symmetry.c.

References addSymresackConss(), nnodes, nodedata, NULL, SCIP_OKAY, SCIPdigraphFree(), SCIPdigraphGetNodeData(), and SCIPfreeBlockMemory.

Referenced by addSSTConss(), and createConflictGraphSST().

◆ addSymresackConss()

static SCIP_RETCODE addSymresackConss ( SCIP scip,
SCIP_PROP prop,
int *  components,
int *  componentbegins,
int  ncomponents 
)
static

adds symresack constraints

Parameters
scipSCIP instance
propsymmetry breaking propagator
componentsarray containing components of symmetry group
componentbeginsarray containing begin positions of components in components array
ncomponentsnumber of components

Definition at line 5414 of file prop_symmetry.c.

References adaptSymmetryDataSST(), addSSTConssOrbitAndUpdateSST(), SYM_Sortgraphcompvars::components, FALSE, ISSSTBINACTIVE, ISSSTCONTACTIVE, ISSSTIMPLINTACTIVE, ISSSTINTACTIVE, NULL, SCIP_Bool, SCIP_CALL, SCIP_MAXSTRLEN, SCIP_OKAY, SCIPaddCons(), SCIPallocBufferArray, SCIPcreateSymbreakCons(), SCIPdebugMsg, SCIPfreeBufferArray, SCIPpropGetData(), SCIPsnprintf(), SYM_HANDLETYPE_ORBITALFIXING, SYM_HANDLETYPE_SST, SYM_HANDLETYPE_SYMBREAK, and TRUE.

Referenced by freeConflictGraphSST(), and tryAddSymmetryHandlingConss().

◆ addSSTConssOrbitAndUpdateSST()

static SCIP_RETCODE addSSTConssOrbitAndUpdateSST ( SCIP scip,
SCIP_DIGRAPH conflictgraph,
SCIP_PROPDATA propdata,
SCIP_VAR **  permvars,
int *  orbits,
int *  orbitbegins,
int  orbitidx,
int  orbitleaderidx,
SCIP_Shortbool orbitvarinconflict,
int  norbitvarinconflict,
int *  nchgbds,
SCIP_Bool  useconflictgraph 
)
static

add Schreier Sims constraints for a specific orbit and update Schreier Sims table

Parameters
scipSCIP instance
conflictgraphconflict graph or NULL if useconflictgraph == FALSE
propdatadata of symmetry propagator
permvarspermvars array
orbitssymmetry orbits
orbitbeginsarray storing begin position for each orbit
orbitidxindex of orbit for Schreier Sims constraints
orbitleaderidxindex of leader variable for Schreier Sims constraints
orbitvarinconflictindicator whether orbitvar is in conflict with orbit leader
norbitvarinconflictnumber of variables in conflict with orbit leader
nchgbdspointer to store number of bound changes (or NULL)
useconflictgraphwhether conflict graph shall be used

Definition at line 5578 of file prop_symmetry.c.

References FALSE, nodedata, NULL, SCIP_Bool, SCIP_CALL, SCIP_LEADERRULE_MAXCONFLICTS, SCIP_LEADERRULE_MAXCONFLICTSINORBIT, SCIP_LEADERTIEBREAKRULE_MAXCONFLICTSINORBIT, SCIP_MAXSTRLEN, SCIP_OKAY, SCIP_Real, SCIPaddCons(), SCIPallocBlockMemoryArray, SCIPcalcMemGrowSize(), SCIPchgVarUb(), SCIPcreateConsLinear(), SCIPdigraphGetNodeData(), SCIPinfinity(), SCIPreallocBlockMemoryArray, SCIPsnprintf(), SCIPvarGetLbLocal(), SCIPvarGetUbLocal(), SCIPvarIsBinary(), selectOrbitLeaderSSTConss(), and TRUE.

Referenced by addSSTConss(), and addSymresackConss().

◆ selectOrbitLeaderSSTConss()

static SCIP_RETCODE selectOrbitLeaderSSTConss ( SCIP scip,
SCIP_DIGRAPH conflictgraph,
SCIP_VAR **  graphvars,
int  ngraphvars,
SCIP_HASHMAP varmap,
SCIP_VAR **  permvars,
int  npermvars,
int *  orbits,
int *  orbitbegins,
int  norbits,
int  leaderrule,
int  tiebreakrule,
SCIP_VARTYPE  leadervartype,
int *  orbitidx,
int *  leaderidx,
SCIP_Shortbool orbitvarinconflict,
int *  norbitvarinconflict,
SCIP_Bool  useconflictgraph,
SCIP_Bool success 
)
static

selection rule of next orbit/leader in orbit for Schreier Sims constraints

Parameters
scipSCIP instance
conflictgraphconflict graph or NULL if useconflictgraph == FALSE
graphvarsvariables encoded in conflict graph
ngraphvarsnumber of variables encoded in conflict graph
varmapmap from variable to node label in conflict graph or NULL if useconflictgraph == FALSE
permvarsvars encoded in a permutation
npermvarsnumber of vars in a permutation
orbitsorbits of stabilizer subgroup
orbitbeginsarray storing the begin position of each orbit in orbits
norbitsnumber of orbits
leaderrulerule to select leader
tiebreakruletie break rule to select leader
leadervartypevariable type of leader
orbitidxpointer to index of selected orbit
leaderidxpointer to leader in orbit
orbitvarinconflictarray to store whether a var in the orbit is conflicting with leader
norbitvarinconflictpointer to store number of vars in the orbit in conflict with leader
useconflictgraphwhether conflict graph shall be used
successpointer to store whether orbit cut be selected successfully

Definition at line 5738 of file prop_symmetry.c.

References addSSTConss(), FALSE, nodedata, NULL, SCIP_LEADERRULE_FIRSTINORBIT, SCIP_LEADERRULE_LASTINORBIT, SCIP_LEADERRULE_MAXCONFLICTS, SCIP_LEADERRULE_MAXCONFLICTSINORBIT, SCIP_LEADERTIEBREAKRULE_MAXCONFLICTSINORBIT, SCIP_LEADERTIEBREAKRULE_MAXORBIT, SCIP_LEADERTIEBREAKRULE_MINORBIT, SCIP_OKAY, SCIPdigraphGetNNodes(), SCIPdigraphGetNodeData(), SCIPdigraphGetNSuccessors(), SCIPdigraphGetSuccessors(), SCIPhashmapGetImageInt(), SCIPvarGetProbindex(), SCIPvarGetType(), and TRUE.

Referenced by addSSTConss(), and addSSTConssOrbitAndUpdateSST().

◆ addSSTConss()

◆ tryAddSymmetryHandlingConss()

static SCIP_RETCODE tryAddSymmetryHandlingConss ( SCIP scip,
SCIP_PROP prop,
int *  nchgbds,
SCIP_Bool earlyterm 
)
static

finds problem symmetries

Parameters
scipSCIP instance
propsymmetry breaking propagator
nchgbdspointer to store number of bound changes (or NULL)
earlytermpointer to store whether we terminated early (or NULL)

Definition at line 6310 of file prop_symmetry.c.

References addSSTConss(), addSymresackConss(), detectAndHandleSubgroups(), detectOrbitopes(), determineSymmetry(), FALSE, freeSymmetryData(), hasNonlinearConstraints(), NULL, performOrbitalFixing(), SCIP_Bool, SCIP_CALL, SCIP_OKAY, SCIPallocBlockMemoryArray, SCIPdebugMsg, SCIPfreeBlockMemoryArrayNull, SCIPgetNBinVars(), SCIPgetNImplVars(), SCIPgetNIntVars(), SCIPisStopped(), SCIPpropGetData(), SYM_SPEC_BINARY, SYM_SPEC_INTEGER, SYM_SPEC_REAL, and TRUE.

Referenced by addSSTConss(), SCIP_DECL_PROPEXITPRE(), SCIP_DECL_PROPINITPRE(), and SCIP_DECL_PROPPRESOL().

◆ performOrbitalFixing()

static SCIP_RETCODE performOrbitalFixing ( SCIP scip,
SCIP_VAR **  permvars,
int  npermvars,
int *  orbits,
int *  orbitbegins,
int  norbits,
SCIP_Bool infeasible,
int *  nfixedzero,
int *  nfixedone 
)
static

performs orbital fixing

Note that we do not have to distinguish between variables that have been fixed or branched to 1, since the stabilizer is with respect to the variables that have been branched to 1. Thus, if an orbit contains a variable that has been branched to 1, the whole orbit only contains variables that have been branched to 1 - and nothing can be fixed.

Parameters
scipSCIP pointer
permvarsvariables
npermvarsnumber of variables
orbitsarray of non-trivial orbits
orbitbeginsarray containing begin positions of new orbits in orbits array
norbitsnumber of orbits
infeasiblepointer to store whether problem is infeasible
nfixedzeropointer to store number of variables fixed to 0
nfixedonepointer to store number of variables fixed to 1

Definition at line 6463 of file prop_symmetry.c.

References computeBranchingVariables(), FALSE, NULL, SCIP_Bool, SCIP_CALL, SCIP_OKAY, SCIP_VARTYPE_BINARY, SCIPdebugMsg, SCIPtightenVarLb(), SCIPtightenVarUb(), SCIPvarGetLbLocal(), SCIPvarGetName(), SCIPvarGetType(), SCIPvarGetUbLocal(), and TRUE.

Referenced by propagateOrbitalFixing(), and tryAddSymmetryHandlingConss().

◆ computeBranchingVariables()

static SCIP_RETCODE computeBranchingVariables ( SCIP scip,
int  nvars,
SCIP_HASHMAP varmap,
SCIP_Shortbool bg1,
int *  bg1list,
int *  nbg1 
)
static

Gets branching variables on the path to root

The variables are added to bg1 and bg1list, which are prefilled with the variables globally fixed to 1.

Parameters
scipSCIP pointer
nvarsnumber of variables
varmapmap of variables to indices in vars array
bg1bitset marking the variables globally fixed or branched to 1
bg1listarray to store the variable indices globally fixed or branched to 1
nbg1pointer to store the number of variables in bg1 and bg1list

Definition at line 6601 of file prop_symmetry.c.

References NULL, propagateOrbitalFixing(), SCIP_BOUNDCHGTYPE_BRANCHING, SCIP_CALL, SCIP_OKAY, SCIP_VARTYPE_BINARY, SCIPboundchgGetBoundchgtype(), SCIPboundchgGetVar(), SCIPdomchgGetBoundchg(), SCIPdomchgGetNBoundchgs(), SCIPgetCurrentNode(), SCIPhashmapExists(), SCIPhashmapGetImageInt(), SCIPnodeGetDepth(), SCIPnodeGetDomchg(), SCIPnodeGetParent(), SCIPprintNodeRootPath(), SCIPvarGetLbLocal(), SCIPvarGetType(), and TRUE.

Referenced by performOrbitalFixing(), and propagateOrbitalFixing().

◆ propagateOrbitalFixing()

static SCIP_RETCODE propagateOrbitalFixing ( SCIP scip,
SCIP_PROPDATA propdata,
SCIP_Bool infeasible,
int *  nprop 
)
static

◆ SCIP_DECL_PROPINITPRE()

static SCIP_DECL_PROPINITPRE ( propInitpreSymmetry  )
static

◆ SCIP_DECL_PROPEXITPRE()

static SCIP_DECL_PROPEXITPRE ( propExitpreSymmetry  )
static

◆ SCIP_DECL_PROPPRESOL()

◆ SCIP_DECL_PROPEXEC()

◆ SCIP_DECL_PROPEXIT()

static SCIP_DECL_PROPEXIT ( propExitSymmetry  )
static

deinitialization method of propagator (called before transformed problem is freed)

Definition at line 7281 of file prop_symmetry.c.

References FALSE, freeSymmetryData(), NULL, PROP_NAME, SCIP_CALL, SCIP_DECL_PROPRESPROP(), SCIP_OKAY, SCIPdebugMsg, SCIPpropGetData(), and SCIPpropGetName().

Referenced by SCIP_DECL_PROPEXEC().

◆ SCIP_DECL_PROPRESPROP()

static SCIP_DECL_PROPRESPROP ( propRespropSymmetry  )
static

propagation conflict resolving method of propagator

Note that this is relatively difficult to obtain: One needs to include all bounds of variables that are responsible for creating the orbit in which the variables that was propagated lies. This includes all variables that are moved by the permutations which are involved in creating the orbit.

Definition at line 7323 of file prop_symmetry.c.

References NULL, SCIP_DECL_PROPFREE(), SCIP_DIDNOTFIND, and SCIP_OKAY.

Referenced by SCIP_DECL_PROPEXIT().

◆ SCIP_DECL_PROPFREE()

static SCIP_DECL_PROPFREE ( propFreeSymmetry  )
static

destructor of propagator to free user data (called when SCIP is exiting)

Definition at line 7335 of file prop_symmetry.c.

References NULL, PROP_NAME, SCIP_OKAY, SCIPdebugMsg, SCIPfreeBlockMemory, SCIPincludePropSymmetry(), SCIPpropGetData(), and SCIPpropGetName().

Referenced by SCIP_DECL_PROPRESPROP().

◆ SCIPincludePropSymmetry()

SCIP_RETCODE SCIPincludePropSymmetry ( SCIP scip)

include symmetry propagator

Parameters
scipSCIP data structure

Definition at line 7359 of file prop_symmetry.c.

References DEFAULT_ADDCONFLICTCUTS, DEFAULT_ADDCONSSTIMING, DEFAULT_ADDSTRONGSBCS, DEFAULT_ADDSYMRESACKS, DEFAULT_ADDWEAKSBCS, DEFAULT_CHECKSYMMETRIES, DEFAULT_COMPRESSSYMMETRIES, DEFAULT_COMPRESSTHRESHOLD, DEFAULT_CONSSADDLP, DEFAULT_DETECTORBITOPES, DEFAULT_DETECTSUBGROUPS, DEFAULT_DISPLAYNORBITVARS, DEFAULT_DOUBLEEQUATIONS, DEFAULT_MAXGENERATORS, DEFAULT_MAXNCONSSSUBGROUP, DEFAULT_OFSYMCOMPTIMING, DEFAULT_ONLYBINARYSYMMETRY, DEFAULT_PERFORMPRESOLVING, DEFAULT_PREFERLESSROWS, DEFAULT_RECOMPUTERESTART, DEFAULT_SSTADDCUTS, DEFAULT_SSTLEADERRULE, DEFAULT_SSTLEADERVARTYPE, DEFAULT_SSTMIXEDCOMPONENTS, DEFAULT_SSTTIEBREAKRULE, DEFAULT_SYMFIXNONBINARYVARS, DEFAULT_USECOLUMNSPARSITY, DEFAULT_USEDYNAMICPROP, EVENTHDLR_SYMMETRY_DESC, EVENTHDLR_SYMMETRY_NAME, FALSE, NULL, PROP_DELAY, PROP_DESC, PROP_FREQ, PROP_NAME, PROP_PRESOL_MAXROUNDS, PROP_PRESOL_PRIORITY, PROP_PRESOLTIMING, PROP_PRIORITY, PROP_TIMING, SCIP_CALL, SCIP_OKAY, SCIPaddBoolParam(), SCIPaddIntParam(), SCIPaddRealParam(), SCIPallocBlockMemory, SCIPgetSymmetry(), SCIPincludeEventhdlrBasic(), SCIPincludeExternalCodeInformation(), SCIPincludePropBasic(), SCIPincludeTable(), SCIPsetPropExit(), SCIPsetPropExitpre(), SCIPsetPropFree(), SCIPsetPropInitpre(), SCIPsetPropPresol(), SCIPsetPropResprop(), SYMcanComputeSymmetry(), SYMsymmetryGetDesc(), SYMsymmetryGetName(), TABLE_DESC_ORBITALFIXING, TABLE_EARLIEST_ORBITALFIXING, TABLE_NAME_ORBITALFIXING, TABLE_POSITION_ORBITALFIXING, and TRUE.

Referenced by SCIP_DECL_PROPFREE(), and SCIPincludeDefaultPlugins().

◆ SCIPgetSymmetry()

SCIP_RETCODE SCIPgetSymmetry ( SCIP scip,
int *  npermvars,
SCIP_VAR ***  permvars,
SCIP_HASHMAP **  permvarmap,
int *  nperms,
int ***  perms,
int ***  permstrans,
SCIP_Real log10groupsize,
SCIP_Bool binvaraffected,
int **  components,
int **  componentbegins,
int **  vartocomponent,
int *  ncomponents 
)

return currently available symmetry group information

Parameters
scipSCIP data structure
npermvarspointer to store number of variables for permutations
permvarspointer to store variables on which permutations act
permvarmappointer to store hash map of permvars (or NULL)
npermspointer to store number of permutations
permspointer to store permutation generators as (nperms x npermvars) matrix (or NULL)
permstranspointer to store permutation generators as (npermvars x nperms) matrix (or NULL)
log10groupsizepointer to store log10 of group size (or NULL)
binvaraffectedpointer to store whether binary variables are affected (or NULL)
componentspointer to store components of symmetry group (or NULL)
componentbeginspointer to store begin positions of components in components array (or NULL)
vartocomponentpointer to store assignment from variable to its component (or NULL)
ncomponentspointer to store number of components (or NULL)

Definition at line 7616 of file prop_symmetry.c.

References SYM_Sortgraphcompvars::components, NULL, PROP_NAME, SCIP_Bool, SCIP_OKAY, SCIP_PLUGINNOTFOUND, SCIPerrorMessage, SCIPfindProp(), SCIPisOrbitalfixingEnabled(), SCIPpropGetData(), and SCIPpropGetName().

Referenced by initOrbits(), and SCIPincludePropSymmetry().

◆ SCIPisOrbitalfixingEnabled()

SCIP_Bool SCIPisOrbitalfixingEnabled ( SCIP scip)

return whether orbital fixing is enabled

Parameters
scipSCIP data structure

Definition at line 7696 of file prop_symmetry.c.

References FALSE, NULL, PROP_NAME, SCIPfindProp(), SCIPgetSymmetryNGenerators(), and SCIPpropGetData().

Referenced by SCIPgetSymmetry().

◆ SCIPgetSymmetryNGenerators()

int SCIPgetSymmetryNGenerators ( SCIP scip)

return number of the symmetry group's generators

Parameters
scipSCIP data structure

Definition at line 7716 of file prop_symmetry.c.

References NULL, PROP_NAME, SCIPfindProp(), and SCIPpropGetData().

Referenced by SCIPisOrbitalfixingEnabled().