# SCIP

Solving Constraint Integer Programs

symmetry_lexred.c File Reference

## Detailed Description

methods for handling symmetries by dynamic lexicographic ordering reduction

This implements lexicographic reduction, which generalizes symresack propagation to work for non-binary variable domains, and is dynamified. Whereas static lexicographic reduction propagates that a vector $$x$$ is lexicographically larger than its permuted counterpart (i.e., $$x \succeq \gamma(x)$$ with $$\succeq$$ being standard elementwise lexicographic comparison), the dynamic variant determines the variable vector ordering dynamically. Just as in orbital reduction (cf. symmetry_orbital.c), the variable order is chosen as the variables branched on from the root node to the focus node. Thus, in node $$\beta$$, we propagate $$\sigma_\beta(x) \succeq \sigma_\beta(\gamma(x))$$, where $$\sigma_\beta(\cdot)$$ permutes and restricts the variable vector such that it corresponds to the branched variables in the order from the rooted path to $$\beta$$.

See Section 4.1 and Example 11 in [vD,H]:
J. van Doornmalen, C. Hojny, "A Unified Framework for Symmetry Handling", preprint, 2023, https://doi.org/10.48550/arXiv.2211.01295.

For dynamic lexicographic reduction, it is crucial that the vectors $$\sigma_\beta(x)$$ are the branching variables up to node $$\beta$$ in the given order. Since SCIP can change the tree structure during solving (re-writing history), we store the original branching decisions at the moment they are made. See event_shadowtree.c .

Definition in file symmetry_lexred.c.

#include "blockmemshell/memory.h"
#include "scip/symmetry_lexred.h"
#include "scip/pub_cons.h"
#include "scip/pub_message.h"
#include "scip/pub_var.h"
#include "scip/struct_var.h"
#include "scip/type_var.h"
#include "scip/scip.h"
#include "scip/scip_branch.h"
#include "scip/scip_conflict.h"
#include "scip/scip_cons.h"
#include "scip/scip_copy.h"
#include "scip/scip_cut.h"
#include "scip/scip_general.h"
#include "scip/scip_lp.h"
#include "scip/scip_mem.h"
#include "scip/scip_message.h"
#include "scip/scip_numerics.h"
#include "scip/scip_param.h"
#include "scip/scip_prob.h"
#include "scip/scip_probing.h"
#include "scip/scip_sol.h"
#include "scip/scip_var.h"
#include "scip/debug.h"
#include "scip/struct_scip.h"
#include "scip/struct_mem.h"
#include "scip/struct_tree.h"
#include "scip/symmetry.h"
#include "scip/event_shadowtree.h"
#include <string.h>

Go to the source code of this file.

## Data Structures

struct  LexRedPermData

struct  NodeDepthBranchIndex

struct  VarArrayNodeDepthBranchIndex

## Typedefs

typedef struct LexRedPermData LEXDATA

typedef struct NodeDepthBranchIndex NODEDEPTHBRANCHINDEX

typedef struct VarArrayNodeDepthBranchIndex VARARRAYNODEDEPTHBRANCHINDEX

## Functions

static SCIP_RETCODE lexdataFree (SCIP *scip, LEXDATA **lexdata)

static SCIP_RETCODE lexdataCreate (SCIP *scip, SCIP_LEXREDDATA *masterdata, LEXDATA **lexdata, SCIP_VAR *const *vars, int nvars, int *perm, SYM_SYMTYPE symtype, SCIP_Real *permvardomaincenter, SCIP_Bool usedynamicorder, SCIP_Bool *success)

static SCIP_DECL_SORTINDCOMP (sortbynodedepthbranchindices)

static int varOrderGetIndex (int *varorder, int pos)

static SCIP_RETCODE getVarOrder (SCIP *scip, SCIP_LEXREDDATA *masterdata, LEXDATA *lexdata, NODEDEPTHBRANCHINDEX *nodedepthbranchindices, int nvarstotal, SCIP_VAR **branchvars, int nbranchvars, int *varorder, int *nselvars, int maxnselvars)

static SCIP_RETCODE getVarBounds (SCIP_VAR *var1, SCIP_VAR *var2, SCIP_Bool peekmode, int varidx1, int varidx2, SCIP_Real *peeklbs, SCIP_Real *peekubs, SCIP_Bool *peekbdset, SCIP_Real *lb1, SCIP_Real *ub1, SCIP_Real *lb2, SCIP_Real *ub2)

static SCIP_Bool alwaysLTshiftedVars (SCIP *scip, SCIP_VAR *var1, SCIP_VAR *var2, SCIP_Real shift1, SCIP_Real shift2, SCIP_Bool isnegated, SCIP_Bool peekmode, int varidx1, int varidx2, SCIP_Real *peeklbs, SCIP_Real *peekubs, SCIP_Bool *peekbdset)

static SCIP_Bool canGTshiftedVars (SCIP *scip, SCIP_VAR *var1, SCIP_VAR *var2, SCIP_Real shift1, SCIP_Real shift2, SCIP_Bool isnegated, SCIP_Bool peekmode, int varidx1, int varidx2, SCIP_Real *peeklbs, SCIP_Real *peekubs, SCIP_Bool *peekbdset)

static SCIP_RETCODE propagateLowerBoundVar (SCIP *scip, SCIP_VAR *var1, SCIP_VAR *var2, SCIP_Real center1, SCIP_Real center2, SCIP_Bool isnegated, SCIP_Bool *infeasible, int *nreductions, SCIP_Bool peekmode, int varidx1, int varidx2, SCIP_Real *peeklbs, SCIP_Real *peekubs, SCIP_Bool *peekbdset)

static SCIP_RETCODE propagateUpperBoundSymVar (SCIP *scip, SCIP_VAR *var1, SCIP_VAR *var2, SCIP_Real center1, SCIP_Real center2, SCIP_Bool isnegated, SCIP_Bool *infeasible, int *nreductions, SCIP_Bool peekmode, int varidx1, int varidx2, SCIP_Real *peeklbs, SCIP_Real *peekubs, SCIP_Bool *peekbdset)

static SCIP_RETCODE propagateSelfReflectionVar (SCIP *scip, SCIP_VAR *var, SCIP_Real center, SCIP_Bool *infeasible, int *nreductions, SCIP_Bool peekmode, int varidx, SCIP_Real *peeklbs, SCIP_Real *peekubs, SCIP_Bool *peekbdset)

static SCIP_RETCODE propagateVariablePair (SCIP *scip, SCIP_VAR *var1, SCIP_VAR *var2, SCIP_Real center1, SCIP_Real center2, SCIP_Bool isnegated, SCIP_Bool *infeasible, int *nreductions, SCIP_Bool peekmode, int varidx1, int varidx2, SCIP_Real *peeklbs, SCIP_Real *peekubs, SCIP_Bool *peekbdset)

static SCIP_RETCODE peekStaticLexredIsFeasible (SCIP *scip, LEXDATA *lexdata, int *varorder, int nselvars, int fixi, int fixj, int fixrow, SCIP_Real fixvaluei, SCIP_Real fixvaluej, SCIP_Bool *peekfeasible, SCIP_Real *peeklbs, SCIP_Real *peekubs, SCIP_Bool *peekbdset)

static SCIP_RETCODE propagateStaticLexred (SCIP *scip, LEXDATA *lexdata, int *varorder, int nselvars, SCIP_Bool *infeasible, int *nreductions)

static SCIP_RETCODE propagateLexredDynamic (SCIP *scip, SCIP_LEXREDDATA *masterdata, LEXDATA *lexdata, NODEDEPTHBRANCHINDEX *nodedepthbranchindices, int nvarstotal, SCIP_VAR **branchvars, int nbranchvars, SCIP_Bool *infeasible, int *nreductions)

static SCIP_RETCODE propagateLexredStatic (SCIP *scip, SCIP_LEXREDDATA *masterdata, LEXDATA *lexdata, SCIP_Bool *infeasible, int *nreductions)

static SCIP_RETCODE propagateLexicographicReductionPerm (SCIP *scip, SCIP_LEXREDDATA *masterdata, LEXDATA *lexdata, NODEDEPTHBRANCHINDEX *nodedepthbranchindices, int nvarstotal, SCIP_VAR **branchvars, int nbranchvars, SCIP_Bool *infeasible, int *nreductions)

static SCIP_RETCODE shadowtreeFillNodeDepthBranchIndices (SCIP *scip, SCIP_LEXREDDATA *masterdata, NODEDEPTHBRANCHINDEX *nodedepthbranchindices, SCIP_VAR **branchvars, int *nbranchvars, SCIP_SHADOWTREE *shadowtree, SCIP_NODE *focusnode, SCIP_Bool *inforesolved)

static SCIP_RETCODE shadowtreeUndoNodeDepthBranchIndices (SCIP *scip, SCIP_LEXREDDATA *masterdata, NODEDEPTHBRANCHINDEX *nodedepthbranchindices, SCIP_VAR **branchvars, int *nbranchvars, SCIP_SHADOWTREE *shadowtree, SCIP_NODE *focusnode)

SCIP_RETCODE SCIPlexicographicReductionGetStatistics (SCIP *scip, SCIP_LEXREDDATA *masterdata, int *nred, int *ncutoff)

SCIP_RETCODE SCIPlexicographicReductionPrintStatistics (SCIP *scip, SCIP_LEXREDDATA *masterdata)

SCIP_RETCODE SCIPlexicographicReductionPropagate (SCIP *scip, SCIP_LEXREDDATA *masterdata, SCIP_Bool *infeasible, int *nred, SCIP_Bool *didrun)

SCIP_RETCODE SCIPlexicographicReductionAddPermutation (SCIP *scip, SCIP_LEXREDDATA *masterdata, SCIP_VAR **permvars, int npermvars, int *perm, SYM_SYMTYPE symtype, SCIP_Real *permvardomaincenter, SCIP_Bool usedynamicorder, SCIP_Bool *success)

SCIP_RETCODE SCIPlexicographicReductionReset (SCIP *scip, SCIP_LEXREDDATA *masterdata)

SCIP_RETCODE SCIPlexicographicReductionFree (SCIP *scip, SCIP_LEXREDDATA **masterdata)

SCIP_RETCODE SCIPincludeLexicographicReduction (SCIP *scip, SCIP_LEXREDDATA **masterdata, SCIP_EVENTHDLR *shadowtreeeventhdlr)

## ◆ LEXDATA

 typedef struct LexRedPermData LEXDATA

Definition at line 100 of file symmetry_lexred.c.

## ◆ NODEDEPTHBRANCHINDEX

 typedef struct NodeDepthBranchIndex NODEDEPTHBRANCHINDEX

Definition at line 125 of file symmetry_lexred.c.

## ◆ VARARRAYNODEDEPTHBRANCHINDEX

 typedef struct VarArrayNodeDepthBranchIndex VARARRAYNODEDEPTHBRANCHINDEX

Definition at line 135 of file symmetry_lexred.c.

## ◆ lexdataFree()

 static SCIP_RETCODE lexdataFree ( SCIP * scip, LEXDATA ** lexdata )
static

frees dynamic lexicographic reduction propagator data

Parameters
 scip SCIP data structure lexdata pointer to individual lexicographic reduction propagator datas

Definition at line 144 of file symmetry_lexred.c.

Referenced by SCIPlexicographicReductionReset().

## ◆ lexdataCreate()

 static SCIP_RETCODE lexdataCreate ( SCIP * scip, SCIP_LEXREDDATA * masterdata, LEXDATA ** lexdata, SCIP_VAR *const * vars, int nvars, int * perm, SYM_SYMTYPE symtype, SCIP_Real * permvardomaincenter, SCIP_Bool usedynamicorder, SCIP_Bool * success )
static

creates dynamic lexicographic reduction propagator data

Fixed points are removed.

Parameters
 scip SCIP data structure masterdata pointer to global data for lexicographic reduction propagator lexdata pointer to store data for permutation to be added vars input variables of the lexicographic reduction propagator nvars input number of variables of the lexicographic reduction propagator perm input permutation of the lexicographic reduction propagator symtype type of symmetries in perm permvardomaincenter array containing center point for each variable domain usedynamicorder whether a dynamic variable order shall be used success to store whether the component is successfully added

Definition at line 222 of file symmetry_lexred.c.

## ◆ SCIP_DECL_SORTINDCOMP()

 static SCIP_DECL_SORTINDCOMP ( sortbynodedepthbranchindices )
static

comparator used in the getVarOrder() function, for sorting an array of NODEDEPTHBRANCHINDEX by depth, then by index

Warning
this function is only meant to be used in the getVarOrder() function
Precondition
datapointer is populated with a VARARRAYNODEDEPTHBRANCHINDEX pointer
the comparator is only called on entries with set (depth, index)-information
the (depth, index)-informations are all different

result: 0: the same index is compared, so the (depth, index)-informations are the same -1: the depth of ind1 is smaller than the depth of ind2, or it's equal and the index is smaller 1: the depth of ind2 is smaller than the depth of ind1, or it's equal and the index is smaller

Definition at line 422 of file symmetry_lexred.c.

## ◆ varOrderGetIndex()

 static int varOrderGetIndex ( int * varorder, int pos )
static

return the index of a variable at a specific position of a variable order

Parameters
 varorder variable order (or NULL) pos position for which index is returned

Definition at line 466 of file symmetry_lexred.c.

References NULL.

Referenced by peekStaticLexredIsFeasible(), and propagateStaticLexred().

## ◆ getVarOrder()

 static SCIP_RETCODE getVarOrder ( SCIP * scip, SCIP_LEXREDDATA * masterdata, LEXDATA * lexdata, NODEDEPTHBRANCHINDEX * nodedepthbranchindices, int nvarstotal, SCIP_VAR ** branchvars, int nbranchvars, int * varorder, int * nselvars, int maxnselvars )
static

gets the variable ordering based on the branching decisions at the node

Parameters
 scip SCIP data structure masterdata pointer to global data for lexicographic reduction propagator lexdata pointer to data for this permutation nodedepthbranchindices array with (depth, index)-information per variable in rooted path to focus node nvarstotal length of that array branchvars array populated with variables branched on in the symvarmap hashset nbranchvars number of elements in branchvars array varorder array to populate with variable order nselvars pointer to number of variables in the ordering maxnselvars maximal size of the number of selected variables

Definition at line 481 of file symmetry_lexred.c.

Referenced by propagateLexredDynamic().

## ◆ getVarBounds()

 static SCIP_RETCODE getVarBounds ( SCIP_VAR * var1, SCIP_VAR * var2, SCIP_Bool peekmode, int varidx1, int varidx2, SCIP_Real * peeklbs, SCIP_Real * peekubs, SCIP_Bool * peekbdset, SCIP_Real * lb1, SCIP_Real * ub1, SCIP_Real * lb2, SCIP_Real * ub2 )
static

gerts local variable bounds or reads bound from peek data

Parameters
 var1 first variable in comparison var2 second variable in comparison peekmode whether function is called in peek mode varidx1 index of var1 (or NULL) varidx2 index of var2 (or NULL) peeklbs lower bounds of variables in peek mode (or NULL) peekubs upper bounds of variables in peek mode (or NULL) peekbdset whether peek bounds have been set (or NULL) lb1 pointer to store lower bound of var1 ub1 pointer to store upper bound of var1 lb2 pointer to store lower bound of var2 ub2 pointer to store upper bound of var2

Definition at line 590 of file symmetry_lexred.c.

References NULL, SCIP_OKAY, SCIPvarGetLbLocal(), and SCIPvarGetUbLocal().

## ◆ alwaysLTshiftedVars()

 static SCIP_Bool alwaysLTshiftedVars ( SCIP * scip, SCIP_VAR * var1, SCIP_VAR * var2, SCIP_Real shift1, SCIP_Real shift2, SCIP_Bool isnegated, SCIP_Bool peekmode, int varidx1, int varidx2, SCIP_Real * peeklbs, SCIP_Real * peekubs, SCIP_Bool * peekbdset )
static

returns whether a shifted variable is always smaller than another shifted variable

Shifts are always (var - shift).

Parameters
 scip SCIP data structure var1 first variable in comparison var2 second variable in comparison shift1 shift of var1 shift2 shift of var2 isnegated whether shift of var2 is negated peekmode whether function is called in peek mode varidx1 index of var1 (or NULL) varidx2 index of var2 (or NULL) peeklbs lower bounds of variables in peek mode (or NULL) peekubs upper bounds of variables in peek mode (or NULL) peekbdset whether peek bounds have been set (or NULL)

Definition at line 644 of file symmetry_lexred.c.

References FALSE, getVarBounds(), NULL, SCIP_CALL_ABORT, SCIP_Real, SCIPisLT(), and TRUE.

Referenced by peekStaticLexredIsFeasible(), and propagateVariablePair().

## ◆ canGTshiftedVars()

 static SCIP_Bool canGTshiftedVars ( SCIP * scip, SCIP_VAR * var1, SCIP_VAR * var2, SCIP_Real shift1, SCIP_Real shift2, SCIP_Bool isnegated, SCIP_Bool peekmode, int varidx1, int varidx2, SCIP_Real * peeklbs, SCIP_Real * peekubs, SCIP_Bool * peekbdset )
static

returns whether a shifted variable can be greater than another shifted variable

Shifts are always (var - shift).

Parameters
 scip SCIP data structure var1 first variable in comparison var2 second variable in comparison shift1 shift of var1 shift2 shift of var2 isnegated whether shift of var2 is negated peekmode whether function is called in peek mode varidx1 index of var1 (or NULL) varidx2 index of var2 (or NULL) peeklbs lower bounds of variables in peek mode (or NULL) peekubs upper bounds of variables in peek mode (or NULL) peekbdset whether peek bounds have been set (or NULL)

Definition at line 691 of file symmetry_lexred.c.

References FALSE, getVarBounds(), NULL, SCIP_CALL_ABORT, SCIP_Real, SCIPisGT(), and TRUE.

Referenced by peekStaticLexredIsFeasible(), and propagateStaticLexred().

## ◆ propagateLowerBoundVar()

 static SCIP_RETCODE propagateLowerBoundVar ( SCIP * scip, SCIP_VAR * var1, SCIP_VAR * var2, SCIP_Real center1, SCIP_Real center2, SCIP_Bool isnegated, SCIP_Bool * infeasible, int * nreductions, SCIP_Bool peekmode, int varidx1, int varidx2, SCIP_Real * peeklbs, SCIP_Real * peekubs, SCIP_Bool * peekbdset )
static

propagates lower bound of first variable in relation x >= y for shifted variables

Parameters
 scip SCIP data structure var1 first variable in pair var2 second variable in pair center1 center of var1 (original var domain) center2 center of var2 (original var domain) isnegated whether var2 is negated by symmetry infeasible pointer to store whether infeasibility is found nreductions pointer to store number of reductions peekmode whether function is called in peek mode varidx1 index of var1 (or NULL) varidx2 index of var2 (or NULL) peeklbs lower bounds of variables in peek mode (or NULL) peekubs upper bounds of variables in peek mode (or NULL) peekbdset whether peek bounds have been set (or NULL)

Definition at line 735 of file symmetry_lexred.c.

Referenced by peekStaticLexredIsFeasible(), and propagateVariablePair().

## ◆ propagateUpperBoundSymVar()

 static SCIP_RETCODE propagateUpperBoundSymVar ( SCIP * scip, SCIP_VAR * var1, SCIP_VAR * var2, SCIP_Real center1, SCIP_Real center2, SCIP_Bool isnegated, SCIP_Bool * infeasible, int * nreductions, SCIP_Bool peekmode, int varidx1, int varidx2, SCIP_Real * peeklbs, SCIP_Real * peekubs, SCIP_Bool * peekbdset )
static

propagates upper bound of second variable in relation x >= y for shifted variables

Parameters
 scip SCIP data structure var1 first variable in pair var2 second variable in pair center1 center of var1 (original var domain) center2 center of var2 (original var domain) isnegated whether var2 is negated by symmetry infeasible pointer to store whether infeasibility is found nreductions pointer to store number of reductions peekmode whether function is called in peek mode varidx1 index of var1 (or NULL) varidx2 index of var2 (or NULL) peeklbs lower bounds of variables in peek mode (or NULL) peekubs upper bounds of variables in peek mode (or NULL) peekbdset whether peek bounds have been set (or NULL)

Definition at line 822 of file symmetry_lexred.c.

Referenced by peekStaticLexredIsFeasible(), and propagateVariablePair().

## ◆ propagateSelfReflectionVar()

 static SCIP_RETCODE propagateSelfReflectionVar ( SCIP * scip, SCIP_VAR * var, SCIP_Real center, SCIP_Bool * infeasible, int * nreductions, SCIP_Bool peekmode, int varidx, SCIP_Real * peeklbs, SCIP_Real * peekubs, SCIP_Bool * peekbdset )
static

propagates x - c >= c - x

Parameters
 scip SCIP data structure var variable center center of var (original var domain) infeasible pointer to store whether infeasibility is found nreductions pointer to store number of reductions peekmode whether function is called in peek mode varidx index of var (or NULL) peeklbs lower bounds of variables in peek mode (or NULL) peekubs upper bounds of variables in peek mode (or NULL) peekbdset whether peek bounds have been set (or NULL)

Definition at line 932 of file symmetry_lexred.c.

Referenced by propagateVariablePair().

## ◆ propagateVariablePair()

 static SCIP_RETCODE propagateVariablePair ( SCIP * scip, SCIP_VAR * var1, SCIP_VAR * var2, SCIP_Real center1, SCIP_Real center2, SCIP_Bool isnegated, SCIP_Bool * infeasible, int * nreductions, SCIP_Bool peekmode, int varidx1, int varidx2, SCIP_Real * peeklbs, SCIP_Real * peekubs, SCIP_Bool * peekbdset )
static

propagates lexicographic order for one pair of symmetric variables

Parameters
 scip SCIP data structure var1 first variable in pair var2 second variable in pair center1 center of var1 (original var domain) center2 center of var2 (original var domain) isnegated whether var2 is negated by symmetry infeasible pointer to store whether infeasibility is found nreductions pointer to store number of reductions peekmode whether function is called in peek mode varidx1 index of var1 (or NULL) varidx2 index of var2 (or NULL) peeklbs lower bounds of variables in peek mode (or NULL) peekubs upper bounds of variables in peek mode (or NULL) peekbdset whether peek bounds have been set (or NULL)

Definition at line 1003 of file symmetry_lexred.c.

Referenced by propagateStaticLexred().

## ◆ peekStaticLexredIsFeasible()

 static SCIP_RETCODE peekStaticLexredIsFeasible ( SCIP * scip, LEXDATA * lexdata, int * varorder, int nselvars, int fixi, int fixj, int fixrow, SCIP_Real fixvaluei, SCIP_Real fixvaluej, SCIP_Bool * peekfeasible, SCIP_Real * peeklbs, SCIP_Real * peekubs, SCIP_Bool * peekbdset )
static

checks if the static lexred with a certain variable ordering is feasible in the hypothetical scenario where variables with indices i and j are fixed to fixvalue (i.e., peeking)

Parameters
 scip SCIP data structure lexdata pointer to data for this permutation varorder array populated with variable order (or NULL for static propagation) nselvars number of variables in the ordering fixi variable index of left fixed column fixj variable index of right fixed column fixrow row index in var ordering, from which to start peeking fixvaluei value on which variables i is fixed fixvaluej value on which variables j is fixed peekfeasible pointer to store whether this is feasible or not peeklbs lower bounds of variables in peek mode (or NULL) peekubs upper bounds of variables in peek mode (or NULL) peekbdset whether peek bounds have been set (or NULL)

Definition at line 1076 of file symmetry_lexred.c.

Referenced by propagateStaticLexred().

## ◆ propagateStaticLexred()

 static SCIP_RETCODE propagateStaticLexred ( SCIP * scip, LEXDATA * lexdata, int * varorder, int nselvars, SCIP_Bool * infeasible, int * nreductions )
static

propagates static lexicographic reduction with specified variable ordering

Parameters
 scip SCIP data structure lexdata pointer to data for this permutation varorder array populated with variable order (or NULL if static propagation) nselvars number of variables in the ordering infeasible pointer to store whether the problem is infeasible nreductions pointer to store the number of found domain reductions

Definition at line 1204 of file symmetry_lexred.c.

Referenced by propagateLexredDynamic(), and propagateLexredStatic().

## ◆ propagateLexredDynamic()

 static SCIP_RETCODE propagateLexredDynamic ( SCIP * scip, SCIP_LEXREDDATA * masterdata, LEXDATA * lexdata, NODEDEPTHBRANCHINDEX * nodedepthbranchindices, int nvarstotal, SCIP_VAR ** branchvars, int nbranchvars, SCIP_Bool * infeasible, int * nreductions )
static

propagation method for a dynamic lexicographic reduction

Parameters
 scip SCIP data structure masterdata pointer to global data for lexicographic reduction propagator lexdata pointer to data for this permutation nodedepthbranchindices array with (depth, index)-information per variable in rooted path to focus node nvarstotal length of nodedepthbranchindices array branchvars array populated with variables branched on nbranchvars number of elements in branchvars array infeasible pointer to store whether the problem is infeasible nreductions pointer to store the number of found domain reductions

Definition at line 1536 of file symmetry_lexred.c.

Referenced by propagateLexicographicReductionPerm().

## ◆ propagateLexredStatic()

 static SCIP_RETCODE propagateLexredStatic ( SCIP * scip, SCIP_LEXREDDATA * masterdata, LEXDATA * lexdata, SCIP_Bool * infeasible, int * nreductions )
static

propagation method for a dynamic lexicographic reduction

Parameters
 scip SCIP data structure masterdata pointer to global data for lexicographic reduction propagator lexdata pointer to data for this permutation infeasible pointer to store whether the problem is infeasible nreductions pointer to store the number of found domain reductions

Definition at line 1586 of file symmetry_lexred.c.

Referenced by propagateLexicographicReductionPerm().

## ◆ propagateLexicographicReductionPerm()

 static SCIP_RETCODE propagateLexicographicReductionPerm ( SCIP * scip, SCIP_LEXREDDATA * masterdata, LEXDATA * lexdata, NODEDEPTHBRANCHINDEX * nodedepthbranchindices, int nvarstotal, SCIP_VAR ** branchvars, int nbranchvars, SCIP_Bool * infeasible, int * nreductions )
static

propagation method for applying dynamic lexicographic reduction for a single permutation

Parameters
 scip SCIP data structure masterdata pointer to global data for lexicographic reduction propagator lexdata pointer to data for this permutation nodedepthbranchindices array with (depth, index)-information per variable in rooted path to focus node nvarstotal length of that array branchvars array populated with variables branched on nbranchvars number of elements in branchvars array infeasible pointer to store whether the problem is infeasible nreductions pointer to store the number of found domain reductions

Definition at line 1614 of file symmetry_lexred.c.

Referenced by SCIPlexicographicReductionPropagate().

 static SCIP_RETCODE shadowtreeFillNodeDepthBranchIndices ( SCIP * scip, SCIP_LEXREDDATA * masterdata, NODEDEPTHBRANCHINDEX * nodedepthbranchindices, SCIP_VAR ** branchvars, int * nbranchvars, SCIP_SHADOWTREE * shadowtree, SCIP_NODE * focusnode, SCIP_Bool * inforesolved )
static

populates array with information of first variable change

Precondition
assuming nodedepthbranchindices is initially clean
Parameters
 scip SCIP data structure masterdata pointer to global data for lexicographic reduction propagator nodedepthbranchindices array to populate branchvars array to populate with variables branched on nbranchvars number of elements in branchvars array shadowtree pointer to shadow tree structure focusnode focusnode to which the rooted path is evaluated inforesolved pointer to store whether information is successfully resolved

Definition at line 1657 of file symmetry_lexred.c.

Referenced by SCIPlexicographicReductionPropagate().

 static SCIP_RETCODE shadowtreeUndoNodeDepthBranchIndices ( SCIP * scip, SCIP_LEXREDDATA * masterdata, NODEDEPTHBRANCHINDEX * nodedepthbranchindices, SCIP_VAR ** branchvars, int * nbranchvars, SCIP_SHADOWTREE * shadowtree, SCIP_NODE * focusnode )
static

cleans nodedepthbranchindices array

Parameters
 scip SCIP data structure masterdata pointer to global data for lexicographic reduction propagator nodedepthbranchindices array populated by nodedepthbranchindices to clean branchvars array populated with variables branched on nbranchvars number of elements in branchvars array shadowtree pointer to shadow tree structure focusnode focusnode to which the rooted path is evaluated

Definition at line 1773 of file symmetry_lexred.c.

Referenced by SCIPlexicographicReductionPropagate().

## ◆ SCIPlexicographicReductionGetStatistics()

 SCIP_RETCODE SCIPlexicographicReductionGetStatistics ( SCIP * scip, SCIP_LEXREDDATA * masterdata, int * nred, int * ncutoff )

prints lexicographic reduction propagation data

Parameters
 scip SCIP data structure masterdata pointer to global data for lexicographic reduction propagator nred total number of reductions applied ncutoff total number of cutoffs applied

Definition at line 1871 of file symmetry_lexred.c.

References VarArrayNodeDepthBranchIndex::masterdata, NULL, and SCIP_OKAY.

Referenced by SCIP_DECL_TABLEOUTPUT().

## ◆ SCIPlexicographicReductionPrintStatistics()

 SCIP_RETCODE SCIPlexicographicReductionPrintStatistics ( SCIP * scip, SCIP_LEXREDDATA * masterdata )

prints lexicographic reduction propagation data

Parameters
 scip SCIP data structure masterdata pointer to global data for lexicographic reduction propagator

Definition at line 1889 of file symmetry_lexred.c.

Referenced by SCIPdisplaySymmetryStatistics().

## ◆ SCIPlexicographicReductionPropagate()

 SCIP_RETCODE SCIPlexicographicReductionPropagate ( SCIP * scip, SCIP_LEXREDDATA * masterdata, SCIP_Bool * infeasible, int * nred, SCIP_Bool * didrun )

applies lexicographic reduction propagation

Parameters
 scip SCIP data structure masterdata pointer to global data for lexicographic reduction propagator infeasible pointer to store whether infeasibility is found nred pointer to store the number of domain reductions didrun a global pointer maintaining if any symmetry propagator has run only set this to TRUE when a reduction is found, never set to FALSE

Definition at line 1922 of file symmetry_lexred.c.

Referenced by propagateSymmetry().

 SCIP_RETCODE SCIPlexicographicReductionAddPermutation ( SCIP * scip, SCIP_LEXREDDATA * masterdata, SCIP_VAR ** permvars, int npermvars, int * perm, SYM_SYMTYPE symtype, SCIP_Real * permvardomaincenter, SCIP_Bool usedynamicorder, SCIP_Bool * success )

adds permutation for lexicographic reduction propagation

Parameters
 scip SCIP data structure masterdata pointer to global data for lexicographic reduction propagator permvars variable array of the permutation npermvars number of variables in that array perm permutation symtype type of symmetries in perm permvardomaincenter array containing center point for each variable domain usedynamicorder whether a dynamic variable order shall be used success to store whether the component is successfully added

Definition at line 2033 of file symmetry_lexred.c.

## ◆ SCIPlexicographicReductionReset()

 SCIP_RETCODE SCIPlexicographicReductionReset ( SCIP * scip, SCIP_LEXREDDATA * masterdata )

resets lexicographic reduction propagation (removes all permutations)

Parameters
 scip SCIP data structure masterdata pointer to global data for lexicographic reduction propagator

Definition at line 2097 of file symmetry_lexred.c.

Referenced by resetDynamicSymmetryHandling(), and SCIPlexicographicReductionFree().

## ◆ SCIPlexicographicReductionFree()

 SCIP_RETCODE SCIPlexicographicReductionFree ( SCIP * scip, SCIP_LEXREDDATA ** masterdata )

frees lexicographic reduction data

Parameters
 scip SCIP data structure masterdata pointer to global data for lexicographic reduction propagator

Definition at line 2135 of file symmetry_lexred.c.

Referenced by SCIP_DECL_PROPFREE().

## ◆ SCIPincludeLexicographicReduction()

 SCIP_RETCODE SCIPincludeLexicographicReduction ( SCIP * scip, SCIP_LEXREDDATA ** masterdata, SCIP_EVENTHDLR * shadowtreeeventhdlr )

initializes structures needed for lexicographic reduction propagation

This is only done exactly once.

Parameters
 scip SCIP data structure masterdata pointer to global data for lexicographic reduction propagator shadowtreeeventhdlr pointer to the shadow tree eventhdlr

Definition at line 2158 of file symmetry_lexred.c.

Referenced by SCIPincludePropSymmetry().