Detailed Description

Constraint handler for linear constraints in their most general form, $lhs <= a^T x <= rhs$ .

Author: Tobias Achterberg; Timo Berthold; Marc Pfetsch; Kati Wolter; Michael Winkler; Gerald Gamrath; Domenico Salvagnin

Linear constraints are separated with a high priority, because they are easy to separate. Instead of using the global cut pool, the same effect can be implemented by adding linear constraints to the root node, such that they are separated each time, the linear constraints are separated. A constraint handler, which generates linear constraints in this way should have a lower separation priority than the linear constraint handler, and it should have a separation frequency that is a multiple of the frequency of the linear constraint handler. In this way, it can be avoided to separate the same cut twice, because if a separation run of the handler is always preceded by a separation of the linear constraints, the priorily added constraints are always satisfied.

Linear constraints are enforced and checked with a very low priority. Checking of (many) linear constraints is much more involved than checking the solution values for integrality. Because we are separating the linear constraints quite often, it is only necessary to enforce them for integral solutions. A constraint handler which generates pool cuts in its enforcing method should have an enforcing priority smaller than that of the linear constraint handler to avoid regenerating constraints which already exist.

Definition in file cons_linear.c.

#include <assert.h>
#include <string.h>
#include <limits.h>
#include <ctype.h>
#include "scip/cons_linear.h"
#include "scip/cons_knapsack.h"
#include "scip/cons_quadratic.h"
#include "scip/cons_nonlinear.h"
#include "scip/pub_misc.h"
#include "scip/debug.h"

Go to the source code of this file.

Macros
#define	CONSHDLR_NAME "linear"

#define	CONSHDLR_DESC "linear constraints of the form lhs <= a^T x <= rhs"

#define	CONSHDLR_SEPAPRIORITY +100000

#define	CONSHDLR_ENFOPRIORITY -1000000

#define	CONSHDLR_CHECKPRIORITY -1000000

#define	CONSHDLR_SEPAFREQ 0

#define	CONSHDLR_PROPFREQ 1

#define	CONSHDLR_EAGERFREQ 100

#define	CONSHDLR_MAXPREROUNDS -1

#define	CONSHDLR_DELAYSEPA FALSE

#define	CONSHDLR_DELAYPROP FALSE

#define	CONSHDLR_NEEDSCONS TRUE

#define	CONSHDLR_PRESOLTIMING (SCIP_PRESOLTIMING_FAST \| SCIP_PRESOLTIMING_EXHAUSTIVE)

#define	CONSHDLR_PROP_TIMING SCIP_PROPTIMING_BEFORELP

#define	EVENTHDLR_NAME "linear"

#define	EVENTHDLR_DESC "bound change event handler for linear constraints"

#define	CONFLICTHDLR_NAME "linear"

#define	CONFLICTHDLR_DESC "conflict handler creating linear constraints"

#define	CONFLICTHDLR_PRIORITY -1000000

#define	DEFAULT_TIGHTENBOUNDSFREQ 1

#define	DEFAULT_MAXROUNDS 5

#define	DEFAULT_MAXROUNDSROOT -1

#define	DEFAULT_MAXSEPACUTS 50

#define	DEFAULT_MAXSEPACUTSROOT 200

#define	DEFAULT_PRESOLPAIRWISE TRUE

#define	DEFAULT_PRESOLUSEHASHING TRUE

#define	DEFAULT_NMINCOMPARISONS 200000

#define	DEFAULT_MINGAINPERNMINCOMP 1e-06

#define	DEFAULT_SORTVARS TRUE

#define	DEFAULT_CHECKRELMAXABS FALSE

#define	DEFAULT_MAXAGGRNORMSCALE 0.0

#define	DEFAULT_MAXEASYACTIVITYDELTA 1e6

#define	DEFAULT_MAXCARDBOUNDDIST 0.0

#define	DEFAULT_SEPARATEALL FALSE

#define	DEFAULT_AGGREGATEVARIABLES TRUE

#define	DEFAULT_SIMPLIFYINEQUALITIES TRUE

#define	DEFAULT_DUALPRESOLVING TRUE

#define	DEFAULT_DETECTCUTOFFBOUND TRUE

#define	DEFAULT_DETECTLOWERBOUND TRUE

#define	DEFAULT_DETECTPARTIALOBJECTIVE TRUE

#define	DEFAULT_RANGEDROWPROPAGATION TRUE

#define	DEFAULT_RANGEDROWARTCONS TRUE

#define	DEFAULT_RANGEDROWMAXDEPTH INT_MAX

#define	DEFAULT_RANGEDROWFREQ 1

#define	DEFAULT_MULTAGGRREMOVE FALSE

#define	MAXDNOM 10000LL

#define	MAXSCALEDCOEF 1e+03

#define	MAXSCALEDCOEFINTEGER 1e+05

#define	HASHSIZE_LINEARCONS 131101

#define	QUADCONSUPGD_PRIORITY 1000000

#define	NONLINCONSUPGD_PRIORITY 1000000

#define	checkMaxActivityDelta(scip, consdata)

#define	MAXTIGHTENROUNDS 10

#define	MAX_CLIQUE_NONZEROS_PER_CONS 1000000

#define	MAXVALRECOMP 1e+06

#define	MAXMULTIAGGRQUOTIENT 1e+03

#define	BINWEIGHT 1

#define	INTWEIGHT 4

#define	CONTWEIGHT 8

#define	MULTIPLIER 2048

#define	MAXCONSPRESOLROUNDS 10

Typedefs
typedef enum Proprule	PROPRULE

typedef struct InferInfo	INFERINFO

Enumerations
enum	Proprule { PROPRULE_1, PROPRULE_2, PROPRULE_3, PROPRULE_4, PROPRULE_INVALID, PROPRULE_INVALID = 0, PROPRULE_1 = 1, PROPRULE_2 = 2, PROPRULE_3 = 3, PROPRULE_4 = 4, PROPRULE_1_CORETIMES = 1, PROPRULE_2_EDGEFINDING = 2, PROPRULE_3_TTEF = 3, PROPRULE_1_RHS = 1, PROPRULE_1_LHS = 2, PROPRULE_1_RANGEDROW = 3, PROPRULE_INVALID = 0, PROPRULE_1, PROPRULE_2, PROPRULE_3, PROPRULE_4, PROPRULE_INVALID, PROPRULE_1, PROPRULE_2, PROPRULE_3, PROPRULE_4, PROPRULE_0, PROPRULE_1, PROPRULE_INTLB, PROPRULE_INTUB, PROPRULE_INVALID }

Functions
static INFERINFO	intToInferInfo (int i)

static int	inferInfoToInt (INFERINFO inferinfo)

static int	inferInfoGetProprule (INFERINFO inferinfo)

static int	inferInfoGetPos (INFERINFO inferinfo)

static INFERINFO	getInferInfo (PROPRULE proprule, int pos)

static int	getInferInt (PROPRULE proprule, int pos)

static SCIP_RETCODE	conshdlrdataEnsureLinconsupgradesSize (SCIP scip, SCIP_CONSHDLRDATA conshdlrdata, int num)

static SCIP_RETCODE	consdataEnsureVarsSize (SCIP scip, SCIP_CONSDATA consdata, int num)

static SCIP_RETCODE	linconsupgradeCreate (SCIP scip, SCIP_LINCONSUPGRADE linconsupgrade, SCIP_DECL_LINCONSUPGD((linconsupgd)), int priority)

static void	linconsupgradeFree (SCIP scip, SCIP_LINCONSUPGRADE *linconsupgrade)

static SCIP_RETCODE	conshdlrdataCreate (SCIP scip, SCIP_CONSHDLRDATA conshdlrdata, SCIP_EVENTHDLR eventhdlr)

static void	conshdlrdataFree (SCIP scip, SCIP_CONSHDLRDATA *conshdlrdata)

static SCIP_Bool	conshdlrdataHasUpgrade (SCIP scip, SCIP_CONSHDLRDATA conshdlrdata, SCIP_DECL_LINCONSUPGD((linconsupgd)), const char conshdlrname)

static SCIP_RETCODE	conshdlrdataIncludeUpgrade (SCIP scip, SCIP_CONSHDLRDATA conshdlrdata, SCIP_LINCONSUPGRADE *linconsupgrade)

static SCIP_RETCODE	lockRounding (SCIP scip, SCIP_CONS cons, SCIP_VAR *var, SCIP_Real val)

static SCIP_RETCODE	unlockRounding (SCIP scip, SCIP_CONS cons, SCIP_VAR *var, SCIP_Real val)

static SCIP_RETCODE	consCatchEvent (SCIP scip, SCIP_CONS cons, SCIP_EVENTHDLR *eventhdlr, int pos)

static SCIP_RETCODE	consDropEvent (SCIP scip, SCIP_CONS cons, SCIP_EVENTHDLR *eventhdlr, int pos)

static SCIP_RETCODE	consCatchAllEvents (SCIP scip, SCIP_CONS cons, SCIP_EVENTHDLR *eventhdlr)

static SCIP_RETCODE	consDropAllEvents (SCIP scip, SCIP_CONS cons, SCIP_EVENTHDLR *eventhdlr)

static SCIP_Bool	needEvents (SCIP *scip)

static SCIP_RETCODE	consdataCreate (SCIP scip, SCIP_CONSDATA consdata, int nvars, SCIP_VAR vars, SCIP_Real vals, SCIP_Real lhs, SCIP_Real rhs)

static SCIP_RETCODE	consdataFree (SCIP scip, SCIP_CONSDATA *consdata)

static SCIP_RETCODE	consdataPrint (SCIP scip, SCIP_CONSDATA consdata, FILE *file)

static void	consdataInvalidateActivities (SCIP_CONSDATA *consdata)

static SCIP_Real	consdataComputePseudoActivity (SCIP scip, SCIP_CONSDATA consdata)

static void	consdataRecomputeMinactivity (SCIP scip, SCIP_CONSDATA consdata)

static void	consdataRecomputeMaxactivity (SCIP scip, SCIP_CONSDATA consdata)

static void	consdataRecomputeGlbMinactivity (SCIP scip, SCIP_CONSDATA consdata)

static void	consdataRecomputeGlbMaxactivity (SCIP scip, SCIP_CONSDATA consdata)

static void	consdataCalcMaxAbsval (SCIP_CONSDATA *consdata)

static void	consdataCheckNonbinvar (SCIP_CONSDATA *consdata)

static void	consdataRecomputeMaxActivityDelta (SCIP scip, SCIP_CONSDATA consdata)

static void	consdataUpdateActivities (SCIP scip, SCIP_CONSDATA consdata, SCIP_VAR *var, SCIP_Real oldbound, SCIP_Real newbound, SCIP_Real val, SCIP_BOUNDTYPE boundtype, SCIP_Bool global, SCIP_Bool checkreliability)

static void	consdataUpdateActivitiesLb (SCIP scip, SCIP_CONSDATA consdata, SCIP_VAR *var, SCIP_Real oldlb, SCIP_Real newlb, SCIP_Real val, SCIP_Bool checkreliability)

static void	consdataUpdateActivitiesUb (SCIP scip, SCIP_CONSDATA consdata, SCIP_VAR *var, SCIP_Real oldub, SCIP_Real newub, SCIP_Real val, SCIP_Bool checkreliability)

static void	consdataUpdateActivitiesGlbLb (SCIP scip, SCIP_CONSDATA consdata, SCIP_Real oldlb, SCIP_Real newlb, SCIP_Real val, SCIP_Bool checkreliability)

static void	consdataUpdateActivitiesGlbUb (SCIP scip, SCIP_CONSDATA consdata, SCIP_Real oldub, SCIP_Real newub, SCIP_Real val, SCIP_Bool checkreliability)

static void	consdataUpdateAddCoef (SCIP scip, SCIP_CONSDATA consdata, SCIP_VAR *var, SCIP_Real val, SCIP_Bool checkreliability)

static void	consdataUpdateDelCoef (SCIP scip, SCIP_CONSDATA consdata, SCIP_VAR *var, SCIP_Real val, SCIP_Bool checkreliability)

static void	consdataUpdateChgCoef (SCIP scip, SCIP_CONSDATA consdata, SCIP_VAR *var, SCIP_Real oldval, SCIP_Real newval, SCIP_Bool checkreliability)

static SCIP_Real	consdataGetMaxAbsval (SCIP_CONSDATA *consdata)

static void	consdataCalcActivities (SCIP scip, SCIP_CONSDATA consdata)

static void	getMinActivity (SCIP scip, SCIP_CONSDATA consdata, int posinf, int neginf, int poshuge, int neghuge, SCIP_Real delta, SCIP_Bool global, SCIP_Bool goodrelax, SCIP_Real minactivity, SCIP_Bool isrelax, SCIP_Bool *issettoinfinity)

static void	getMaxActivity (SCIP scip, SCIP_CONSDATA consdata, int posinf, int neginf, int poshuge, int neghuge, SCIP_Real delta, SCIP_Bool global, SCIP_Bool goodrelax, SCIP_Real maxactivity, SCIP_Bool isrelax, SCIP_Bool *issettoinfinity)

static void	consdataGetActivityBounds (SCIP scip, SCIP_CONSDATA consdata, SCIP_Bool goodrelax, SCIP_Real minactivity, SCIP_Real maxactivity, SCIP_Bool minisrelax, SCIP_Bool maxisrelax)

static void	consdataGetReliableResidualActivity (SCIP scip, SCIP_CONSDATA consdata, SCIP_VAR cancelvar, SCIP_Real resactivity, SCIP_Bool isminresact, SCIP_Bool useglobalbounds)

static void	consdataGetActivityResiduals (SCIP scip, SCIP_CONSDATA consdata, SCIP_VAR var, SCIP_Real val, SCIP_Bool goodrelax, SCIP_Real minresactivity, SCIP_Real maxresactivity, SCIP_Bool minisrelax, SCIP_Bool maxisrelax, SCIP_Bool isminsettoinfinity, SCIP_Bool *ismaxsettoinfinity)

static void	consdataGetGlbActivityBounds (SCIP scip, SCIP_CONSDATA consdata, SCIP_Bool goodrelax, SCIP_Real glbminactivity, SCIP_Real glbmaxactivity, SCIP_Bool minisrelax, SCIP_Bool maxisrelax, SCIP_Bool isminsettoinfinity, SCIP_Bool ismaxsettoinfinity)

static void	consdataGetGlbActivityResiduals (SCIP scip, SCIP_CONSDATA consdata, SCIP_VAR var, SCIP_Real val, SCIP_Bool goodrelax, SCIP_Real minresactivity, SCIP_Real maxresactivity, SCIP_Bool minisrelax, SCIP_Bool maxisrelax, SCIP_Bool isminsettoinfinity, SCIP_Bool *ismaxsettoinfinity)

static SCIP_Real	consdataGetActivity (SCIP scip, SCIP_CONSDATA consdata, SCIP_SOL *sol)

static SCIP_Real	consdataGetFeasibility (SCIP scip, SCIP_CONSDATA consdata, SCIP_SOL *sol)

static SCIP_Longint	getVarSignature (SCIP_VAR *var)

static void	consdataUpdateSignatures (SCIP_CONSDATA *consdata, int pos)

static void	consdataCalcSignatures (SCIP_CONSDATA *consdata)

static	SCIP_DECL_SORTINDCOMP (consdataCompVar)

static void	permSortConsdata (SCIP_CONSDATA consdata, int perm, int nvars)

static SCIP_RETCODE	consdataSort (SCIP scip, SCIP_CONSDATA consdata)

static SCIP_RETCODE	chgLhs (SCIP scip, SCIP_CONS cons, SCIP_Real lhs)

static SCIP_RETCODE	chgRhs (SCIP scip, SCIP_CONS cons, SCIP_Real rhs)

static SCIP_RETCODE	addCoef (SCIP scip, SCIP_CONS cons, SCIP_VAR *var, SCIP_Real val)

static SCIP_RETCODE	delCoefPos (SCIP scip, SCIP_CONS cons, int pos)

static SCIP_RETCODE	chgCoefPos (SCIP scip, SCIP_CONS cons, int pos, SCIP_Real newval)

static SCIP_RETCODE	scaleCons (SCIP scip, SCIP_CONS cons, SCIP_Real scalar)

static SCIP_RETCODE	performVarDeletions (SCIP scip, SCIP_CONSHDLR conshdlr, SCIP_CONS **conss, int nconss)

static SCIP_RETCODE	normalizeCons (SCIP scip, SCIP_CONS cons)

static SCIP_RETCODE	mergeMultiples (SCIP scip, SCIP_CONS cons)

static SCIP_RETCODE	applyFixings (SCIP scip, SCIP_CONS cons, SCIP_Bool *infeasible)

static SCIP_RETCODE	addConflictBounds (SCIP scip, SCIP_CONS cons, SCIP_VAR infervar, SCIP_BDCHGIDX bdchgidx, int inferpos, SCIP_Bool reasonisrhs)

static SCIP_RETCODE	addConflictFixedVars (SCIP scip, SCIP_CONS cons, SCIP_VAR infervar, SCIP_BDCHGIDX bdchgidx, int inferpos)

static SCIP_RETCODE	addConflictReasonVars (SCIP scip, SCIP_VAR vars, int nvars, SCIP_VAR var, SCIP_Real bound)

static SCIP_RETCODE	resolvePropagation (SCIP scip, SCIP_CONS cons, SCIP_VAR infervar, INFERINFO inferinfo, SCIP_BOUNDTYPE boundtype, SCIP_BDCHGIDX bdchgidx, SCIP_RESULT *result)

static SCIP_RETCODE	analyzeConflict (SCIP scip, SCIP_CONS cons, SCIP_Bool reasonisrhs)

static SCIP_Bool	canTightenBounds (SCIP scip, SCIP_CONS cons)

static SCIP_RETCODE	tightenVarUb (SCIP scip, SCIP_CONS cons, int pos, PROPRULE proprule, SCIP_Real newub, SCIP_Real oldub, SCIP_Bool cutoff, int nchgbds, SCIP_Bool force)

static SCIP_RETCODE	tightenVarLb (SCIP scip, SCIP_CONS cons, int pos, PROPRULE proprule, SCIP_Real newlb, SCIP_Real oldlb, SCIP_Bool cutoff, int nchgbds, SCIP_Bool force)

static SCIP_RETCODE	tightenVarBoundsEasy (SCIP scip, SCIP_CONS cons, int pos, SCIP_Bool cutoff, int nchgbds, SCIP_Bool force)

static SCIP_RETCODE	analyzeConflictRangedRow (SCIP scip, SCIP_CONS cons, SCIP_VAR *vars, int nvars, SCIP_VAR var, SCIP_Real bound)

static SCIP_RETCODE	rangedRowPropagation (SCIP scip, SCIP_CONS cons, SCIP_Bool cutoff, int nfixedvars, int nchgbds, int naddconss)

static SCIP_RETCODE	tightenVarBounds (SCIP scip, SCIP_CONS cons, int pos, SCIP_Bool cutoff, int nchgbds, SCIP_Bool force)

static SCIP_RETCODE	tightenBounds (SCIP scip, SCIP_CONS cons, SCIP_Real maxeasyactivitydelta, SCIP_Bool sortvars, SCIP_Bool cutoff, int nchgbds)

static SCIP_RETCODE	checkCons (SCIP scip, SCIP_CONS cons, SCIP_SOL sol, SCIP_Bool checklprows, SCIP_Bool checkrelmaxabs, SCIP_Bool violated)

static SCIP_RETCODE	createRow (SCIP scip, SCIP_CONS cons)

static SCIP_RETCODE	addRelaxation (SCIP scip, SCIP_CONS cons, SCIP_SOL sol, SCIP_Bool cutoff)

static SCIP_RETCODE	separateCons (SCIP scip, SCIP_CONS cons, SCIP_CONSHDLRDATA conshdlrdata, SCIP_SOL sol, SCIP_Bool separatecards, SCIP_Bool separateall, int ncuts, SCIP_Bool cutoff)

static SCIP_RETCODE	propagateCons (SCIP scip, SCIP_CONS cons, SCIP_Bool tightenbounds, SCIP_Bool rangedrowpropagation, SCIP_Real maxeasyactivitydelta, SCIP_Bool sortvars, SCIP_Bool cutoff, int nchgbds)

static SCIP_RETCODE	fixVariables (SCIP scip, SCIP_CONS cons, SCIP_Bool cutoff, int nfixedvars)

static SCIP_RETCODE	extractCliques (SCIP scip, SCIP_CONS cons, SCIP_Real maxeasyactivitydelta, SCIP_Bool sortvars, int nfixedvars, int nchgbds, SCIP_Bool *cutoff)

static SCIP_RETCODE	tightenSides (SCIP scip, SCIP_CONS cons, int *nchgsides)

static SCIP_RETCODE	consdataTightenCoefs (SCIP scip, SCIP_CONS cons, int nchgcoefs, int nchgsides)

static SCIP_RETCODE	convertUnaryEquality (SCIP scip, SCIP_CONS cons, SCIP_Bool cutoff, int nfixedvars, int *ndelconss)

static SCIP_RETCODE	convertBinaryEquality (SCIP scip, SCIP_CONS cons, SCIP_Bool cutoff, int naggrvars, int *ndelconss)

static void	getNewSidesAfterAggregation (SCIP scip, SCIP_CONSDATA consdata, SCIP_VAR slackvar, SCIP_Real slackcoef, SCIP_Real newlhs, SCIP_Real *newrhs)

static SCIP_RETCODE	convertLongEquality (SCIP scip, SCIP_CONSHDLRDATA conshdlrdata, SCIP_CONS cons, SCIP_Bool cutoff, int naggrvars, int ndelconss)

static SCIP_Bool	checkEqualObjective (SCIP scip, SCIP_CONSDATA consdata, SCIP_Real scale, SCIP_Real offset)

static SCIP_RETCODE	checkPartialObjective (SCIP scip, SCIP_CONS cons, SCIP_CONSHDLRDATA *conshdlrdata)

static SCIP_RETCODE	updateCutoffbound (SCIP scip, SCIP_CONS cons, SCIP_Real primalbound)

static SCIP_RETCODE	checkParallelObjective (SCIP scip, SCIP_CONS cons, SCIP_CONSHDLRDATA *conshdlrdata)

static SCIP_RETCODE	convertEquality (SCIP scip, SCIP_CONS cons, SCIP_CONSHDLRDATA conshdlrdata, SCIP_Bool cutoff, int nfixedvars, int naggrvars, int *ndelconss)

static SCIP_Bool	consdataIsResidualIntegral (SCIP scip, SCIP_CONSDATA consdata, int pos, SCIP_Real val)

static void	calculateMinvalAndMaxval (SCIP scip, SCIP_Real side, SCIP_Real val, SCIP_Real minresactivity, SCIP_Real maxresactivity, SCIP_Real minval, SCIP_Real *maxval)

static SCIP_RETCODE	dualPresolve (SCIP scip, SCIP_CONS cons, SCIP_Bool cutoff, int nfixedvars, int naggrvars, int ndelconss)

static int	getVarWeight (SCIP_VAR *var)

static SCIP_RETCODE	aggregateVariables (SCIP scip, SCIP_CONS cons, SCIP_Bool cutoff, int nfixedvars, int naggrvars, int ndelconss)

static	SCIP_DECL_SORTINDCOMP (consdataCompSim)

static SCIP_RETCODE	rangedRowSimplify (SCIP scip, SCIP_CONS cons, int nchgcoefs, int nchgsides)

static SCIP_RETCODE	simplifyInequalities (SCIP scip, SCIP_CONS cons, int nchgcoefs, int nchgsides)

static SCIP_RETCODE	aggregateConstraints (SCIP scip, SCIP_CONS cons0, SCIP_CONS cons1, int commonidx0, int commonidx1, int diffidx0minus1, int diffidx1minus0, int nvarscommon, int commonidxweight, int diffidx0minus1weight, int diffidx1minus0weight, SCIP_Real maxaggrnormscale, int nchgcoefs, SCIP_Bool *aggregated)

static	SCIP_DECL_HASHGETKEY (hashGetKeyLinearcons)

static	SCIP_DECL_HASHKEYEQ (hashKeyEqLinearcons)

static	SCIP_DECL_HASHKEYVAL (hashKeyValLinearcons)

static SCIP_RETCODE	detectRedundantConstraints (SCIP scip, BMS_BLKMEM blkmem, SCIP_CONS *conss, int nconss, int firstchange, SCIP_Bool cutoff, int ndelconss, int *nchgsides)

static SCIP_RETCODE	preprocessConstraintPairs (SCIP scip, SCIP_CONS conss, int firstchange, int chkind, SCIP_Real maxaggrnormscale, SCIP_Bool cutoff, int ndelconss, int nchgsides, int *nchgcoefs)

static SCIP_RETCODE	fullDualPresolve (SCIP scip, SCIP_CONS conss, int nconss, SCIP_Bool cutoff, int *nchgbds)

static	SCIP_DECL_CONSHDLRCOPY (conshdlrCopyLinear)

static	SCIP_DECL_CONSFREE (consFreeLinear)

static	SCIP_DECL_CONSINIT (consInitLinear)

static	SCIP_DECL_CONSEXIT (consExitLinear)

static	SCIP_DECL_CONSEXITPRE (consExitpreLinear)

static	SCIP_DECL_CONSEXITSOL (consExitsolLinear)

static	SCIP_DECL_CONSDELETE (consDeleteLinear)

static	SCIP_DECL_CONSTRANS (consTransLinear)

static	SCIP_DECL_CONSINITLP (consInitlpLinear)

static	SCIP_DECL_CONSSEPALP (consSepalpLinear)

static	SCIP_DECL_CONSSEPASOL (consSepasolLinear)

static	SCIP_DECL_CONSENFOLP (consEnfolpLinear)

static	SCIP_DECL_CONSENFOPS (consEnfopsLinear)

static	SCIP_DECL_CONSCHECK (consCheckLinear)

static	SCIP_DECL_CONSPROP (consPropLinear)

static	SCIP_DECL_CONSPRESOL (consPresolLinear)

static	SCIP_DECL_CONSRESPROP (consRespropLinear)

static	SCIP_DECL_CONSLOCK (consLockLinear)

static	SCIP_DECL_CONSDELVARS (consDelvarsLinear)

static	SCIP_DECL_CONSPRINT (consPrintLinear)

static	SCIP_DECL_CONSCOPY (consCopyLinear)

static	SCIP_DECL_CONSPARSE (consParseLinear)

static	SCIP_DECL_CONSGETVARS (consGetVarsLinear)

static	SCIP_DECL_CONSGETNVARS (consGetNVarsLinear)

static	SCIP_DECL_EVENTEXEC (eventExecLinear)

static	SCIP_DECL_CONFLICTEXEC (conflictExecLinear)

static	SCIP_DECL_QUADCONSUPGD (upgradeConsQuadratic)

static	SCIP_DECL_NONLINCONSUPGD (upgradeConsNonlinear)

SCIP_RETCODE	SCIPincludeConshdlrLinear (SCIP *scip)

SCIP_RETCODE	SCIPincludeLinconsUpgrade (SCIP scip, SCIP_DECL_LINCONSUPGD((linconsupgd)), int priority, const char *conshdlrname)

SCIP_RETCODE	SCIPcreateConsLinear (SCIP scip, SCIP_CONS cons, const char name, int nvars, SCIP_VAR *vars, SCIP_Real vals, SCIP_Real lhs, SCIP_Real rhs, SCIP_Bool initial, SCIP_Bool separate, SCIP_Bool enforce, SCIP_Bool check, SCIP_Bool propagate, SCIP_Bool local, SCIP_Bool modifiable, SCIP_Bool dynamic, SCIP_Bool removable, SCIP_Bool stickingatnode)

SCIP_RETCODE	SCIPcreateConsBasicLinear (SCIP scip, SCIP_CONS cons, const char name, int nvars, SCIP_VAR *vars, SCIP_Real vals, SCIP_Real lhs, SCIP_Real rhs)

SCIP_RETCODE	SCIPcopyConsLinear (SCIP scip, SCIP_CONS cons, SCIP sourcescip, const char name, int nvars, SCIP_VAR sourcevars, SCIP_Real sourcecoefs, SCIP_Real lhs, SCIP_Real rhs, SCIP_HASHMAP varmap, SCIP_HASHMAP consmap, SCIP_Bool initial, SCIP_Bool separate, SCIP_Bool enforce, SCIP_Bool check, SCIP_Bool propagate, SCIP_Bool local, SCIP_Bool modifiable, SCIP_Bool dynamic, SCIP_Bool removable, SCIP_Bool stickingatnode, SCIP_Bool global, SCIP_Bool *valid)

SCIP_RETCODE	SCIPaddCoefLinear (SCIP scip, SCIP_CONS cons, SCIP_VAR *var, SCIP_Real val)

SCIP_RETCODE	SCIPchgCoefLinear (SCIP scip, SCIP_CONS cons, SCIP_VAR *var, SCIP_Real val)

SCIP_RETCODE	SCIPdelCoefLinear (SCIP scip, SCIP_CONS cons, SCIP_VAR *var)

SCIP_Real	SCIPgetLhsLinear (SCIP scip, SCIP_CONS cons)

SCIP_Real	SCIPgetRhsLinear (SCIP scip, SCIP_CONS cons)

SCIP_RETCODE	SCIPchgLhsLinear (SCIP scip, SCIP_CONS cons, SCIP_Real lhs)

SCIP_RETCODE	SCIPchgRhsLinear (SCIP scip, SCIP_CONS cons, SCIP_Real rhs)

int	SCIPgetNVarsLinear (SCIP scip, SCIP_CONS cons)

SCIP_VAR **	SCIPgetVarsLinear (SCIP scip, SCIP_CONS cons)

SCIP_Real *	SCIPgetValsLinear (SCIP scip, SCIP_CONS cons)

SCIP_Real	SCIPgetActivityLinear (SCIP scip, SCIP_CONS cons, SCIP_SOL *sol)

SCIP_Real	SCIPgetFeasibilityLinear (SCIP scip, SCIP_CONS cons, SCIP_SOL *sol)

SCIP_Real	SCIPgetDualsolLinear (SCIP scip, SCIP_CONS cons)

SCIP_Real	SCIPgetDualfarkasLinear (SCIP scip, SCIP_CONS cons)

SCIP_ROW *	SCIPgetRowLinear (SCIP scip, SCIP_CONS cons)

SCIP_RETCODE	SCIPupgradeConsLinear (SCIP scip, SCIP_CONS cons, SCIP_CONS **upgdcons)

Macro Definition Documentation

#define CONSHDLR_NAME "linear"

Definition at line 61 of file cons_linear.c.

Referenced by SCIP_DECL_CONSCHECK(), SCIP_DECL_CONSENFOLP(), SCIP_DECL_CONSHDLRCOPY(), SCIPchgLhsLinear(), SCIPchgRhsLinear(), SCIPcopyConsLinear(), SCIPcreateConsLinear(), and SCIPdelCoefLinear().

#define CONSHDLR_DESC "linear constraints of the form lhs <= a^T x <= rhs"

Definition at line 62 of file cons_linear.c.

#define CONSHDLR_SEPAPRIORITY +100000

priority of the constraint handler for separation

Definition at line 63 of file cons_linear.c.

#define CONSHDLR_ENFOPRIORITY -1000000

priority of the constraint handler for constraint enforcing

Definition at line 64 of file cons_linear.c.

#define CONSHDLR_CHECKPRIORITY -1000000

priority of the constraint handler for checking feasibility

Definition at line 65 of file cons_linear.c.

#define CONSHDLR_SEPAFREQ 0

frequency for separating cuts; zero means to separate only in the root node

Definition at line 66 of file cons_linear.c.

#define CONSHDLR_PROPFREQ 1

frequency for propagating domains; zero means only preprocessing propagation

Definition at line 67 of file cons_linear.c.

#define CONSHDLR_EAGERFREQ 100

frequency for using all instead of only the useful constraints in separation, propagation and enforcement, -1 for no eager evaluations, 0 for first only

Definition at line 68 of file cons_linear.c.

#define CONSHDLR_MAXPREROUNDS -1

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

Definition at line 71 of file cons_linear.c.

#define CONSHDLR_DELAYSEPA FALSE

should separation method be delayed, if other separators found cuts?

Definition at line 72 of file cons_linear.c.

#define CONSHDLR_DELAYPROP FALSE

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

Definition at line 73 of file cons_linear.c.

#define CONSHDLR_NEEDSCONS TRUE

should the constraint handler be skipped, if no constraints are available?

Definition at line 74 of file cons_linear.c.

#define CONSHDLR_PRESOLTIMING (SCIP_PRESOLTIMING_FAST | SCIP_PRESOLTIMING_EXHAUSTIVE)

presolving timing of the constraint handler (fast, medium, or exhaustive)

Definition at line 76 of file cons_linear.c.

#define CONSHDLR_PROP_TIMING SCIP_PROPTIMING_BEFORELP

Definition at line 77 of file cons_linear.c.

#define EVENTHDLR_NAME "linear"

Definition at line 79 of file cons_linear.c.

Referenced by SCIP_DECL_CONSGETNVARS(), and SCIP_DECL_NONLINCONSUPGD().

#define EVENTHDLR_DESC "bound change event handler for linear constraints"

Definition at line 80 of file cons_linear.c.

Referenced by SCIP_DECL_NONLINCONSUPGD().

#define CONFLICTHDLR_NAME "linear"

Definition at line 82 of file cons_linear.c.

#define CONFLICTHDLR_DESC "conflict handler creating linear constraints"

Definition at line 83 of file cons_linear.c.

#define CONFLICTHDLR_PRIORITY -1000000

Definition at line 84 of file cons_linear.c.

#define DEFAULT_TIGHTENBOUNDSFREQ 1

multiplier on propagation frequency, how often the bounds are tightened

Definition at line 86 of file cons_linear.c.

#define DEFAULT_MAXROUNDS 5

maximal number of separation rounds per node (-1: unlimited)

Definition at line 87 of file cons_linear.c.

#define DEFAULT_MAXROUNDSROOT -1

maximal number of separation rounds in the root node (-1: unlimited)

Definition at line 88 of file cons_linear.c.

#define DEFAULT_MAXSEPACUTS 50

maximal number of cuts separated per separation round

Definition at line 89 of file cons_linear.c.

#define DEFAULT_MAXSEPACUTSROOT 200

maximal number of cuts separated per separation round in root node

Definition at line 90 of file cons_linear.c.

#define DEFAULT_PRESOLPAIRWISE TRUE

should pairwise constraint comparison be performed in presolving?

Definition at line 91 of file cons_linear.c.

#define DEFAULT_PRESOLUSEHASHING TRUE

should hash table be used for detecting redundant constraints in advance

Definition at line 92 of file cons_linear.c.

#define DEFAULT_NMINCOMPARISONS 200000

number for minimal pairwise presolving comparisons

Definition at line 93 of file cons_linear.c.

#define DEFAULT_MINGAINPERNMINCOMP 1e-06

minimal gain per minimal pairwise presolving comparisons to repeat pairwise comparison round

Definition at line 94 of file cons_linear.c.

#define DEFAULT_SORTVARS TRUE

should variables be sorted after presolve w.r.t their coefficient absolute for faster propagation?

Definition at line 97 of file cons_linear.c.

#define DEFAULT_CHECKRELMAXABS FALSE

should the violation for a constraint with side 0.0 be checked relative to 1.0 (FALSE) or to the maximum absolute value in the activity (TRUE)?

Definition at line 100 of file cons_linear.c.

#define DEFAULT_MAXAGGRNORMSCALE 0.0

maximal allowed relative gain in maximum norm for constraint aggregation (0.0: disable constraint aggregation)

Definition at line 103 of file cons_linear.c.

#define DEFAULT_MAXEASYACTIVITYDELTA 1e6

maximum activity delta to run easy propagation on linear constraint (faster, but numerically less stable)

Definition at line 106 of file cons_linear.c.

#define DEFAULT_MAXCARDBOUNDDIST 0.0

maximal relative distance from current node's dual bound to primal bound compared to best node's dual bound for separating knapsack cardinality cuts

Definition at line 109 of file cons_linear.c.

#define DEFAULT_SEPARATEALL FALSE

should all constraints be subject to cardinality cut generation instead of only the ones with non-zero dual value?

Definition at line 112 of file cons_linear.c.

#define DEFAULT_AGGREGATEVARIABLES TRUE

should presolving search for redundant variables in equations

Definition at line 115 of file cons_linear.c.

#define DEFAULT_SIMPLIFYINEQUALITIES TRUE

should presolving try to simplify inequalities

Definition at line 116 of file cons_linear.c.

#define DEFAULT_DUALPRESOLVING TRUE

should dual presolving steps be performed?

Definition at line 117 of file cons_linear.c.

#define DEFAULT_DETECTCUTOFFBOUND TRUE

should presolving try to detect constraints parallel to the objective function defining an upper bound and prevent these constraints from entering the LP

Definition at line 118 of file cons_linear.c.

#define DEFAULT_DETECTLOWERBOUND TRUE

should presolving try to detect constraints parallel to the objective function defining a lower bound and prevent these constraints from entering the LP

Definition at line 123 of file cons_linear.c.

#define DEFAULT_DETECTPARTIALOBJECTIVE TRUE

should presolving try to detect subsets of constraints parallel to the objective function

Definition at line 128 of file cons_linear.c.

#define DEFAULT_RANGEDROWPROPAGATION TRUE

should we perform ranged row propagation

Definition at line 131 of file cons_linear.c.

#define DEFAULT_RANGEDROWARTCONS TRUE

should presolving and propagation extract sub-constraints from ranged rows and equations?

Definition at line 132 of file cons_linear.c.

#define DEFAULT_RANGEDROWMAXDEPTH INT_MAX

maximum depth to apply ranged row propagation

Definition at line 133 of file cons_linear.c.

#define DEFAULT_RANGEDROWFREQ 1

frequency for applying ranged row propagation

Definition at line 134 of file cons_linear.c.

#define DEFAULT_MULTAGGRREMOVE FALSE

should multi-aggregations only be performed if the constraint can be removed afterwards?

Definition at line 136 of file cons_linear.c.

#define MAXDNOM 10000LL

maximal denominator for simple rational fixed values

Definition at line 140 of file cons_linear.c.

Referenced by SCIP_DECL_PRESOLEXEC().

#define MAXSCALEDCOEF 1e+03

maximal coefficient value after scaling

Definition at line 141 of file cons_linear.c.

#define MAXSCALEDCOEFINTEGER 1e+05

maximal coefficient value after scaling if all variables are of integral type

Definition at line 142 of file cons_linear.c.

#define HASHSIZE_LINEARCONS 131101

minimal size of hash table in linear constraint tables

Definition at line 148 of file cons_linear.c.

#define QUADCONSUPGD_PRIORITY 1000000

priority of the constraint handler for upgrading of quadratic constraints

Definition at line 150 of file cons_linear.c.

#define NONLINCONSUPGD_PRIORITY 1000000

priority of the constraint handler for upgrading of nonlinear constraints

Definition at line 151 of file cons_linear.c.

#define checkMaxActivityDelta	(	scip,
		consdata
	)

Definition at line 1373 of file cons_linear.c.

Referenced by consdataCheckNonbinvar().

#define MAXTIGHTENROUNDS 10

Definition at line 6665 of file cons_linear.c.

#define MAX_CLIQUE_NONZEROS_PER_CONS 1000000

Definition at line 7390 of file cons_linear.c.

#define MAXVALRECOMP 1e+06

Definition at line 8472 of file cons_linear.c.

#define MAXMULTIAGGRQUOTIENT 1e+03

Definition at line 9094 of file cons_linear.c.

#define BINWEIGHT 1

Definition at line 10501 of file cons_linear.c.

#define INTWEIGHT 4

Definition at line 10502 of file cons_linear.c.

#define CONTWEIGHT 8

Definition at line 10503 of file cons_linear.c.

#define MULTIPLIER 2048

Definition at line 12430 of file cons_linear.c.

#define MAXCONSPRESOLROUNDS 10

Definition at line 14765 of file cons_linear.c.

Typedef Documentation

typedef enum Proprule PROPRULE

Definition at line 340 of file cons_linear.c.

typedef struct InferInfo INFERINFO

Definition at line 355 of file cons_linear.c.

Enumeration Type Documentation

enum Proprule

Enumerator
PROPRULE_1	left hand side and bounds on z -> lower bound on x
PROPRULE_2	left hand side and upper bound on x -> bound on z
PROPRULE_3	right hand side and bounds on z -> upper bound on x
PROPRULE_4	right hand side and lower bound on x -> bound on z
PROPRULE_INVALID	propagation was applied without a specific propagation rule
PROPRULE_INVALID	propagation was applied without a specific propagation rule
PROPRULE_1	v_i = FALSE => r = FALSE
PROPRULE_2	r = TRUE => v_i = TRUE for all i
PROPRULE_3	v_i = TRUE for all i => r = TRUE
PROPRULE_4	r = FALSE, v_i = TRUE for all i except j => v_j = FALSE
PROPRULE_1_CORETIMES	core-time propagator
PROPRULE_2_EDGEFINDING	edge-finder
PROPRULE_3_TTEF	time-table edeg-finding
PROPRULE_1_RHS	activity residuals of all other variables tighten bounds of single variable due to the right hand side of the inequality
PROPRULE_1_LHS	activity residuals of all other variables tighten bounds of single variable due to the left hand side of the inequality
PROPRULE_1_RANGEDROW	fixed variables and gcd of all left variables tighten bounds of a single variable in this reanged row
PROPRULE_INVALID	propagation was applied without a specific propagation rule
PROPRULE_1	v_i = TRUE => r = TRUE
PROPRULE_2	r = FALSE => v_i = FALSE for all i
PROPRULE_3	v_i = FALSE for all i => r = FALSE
PROPRULE_4	r = TRUE, v_i = FALSE for all i except j => v_j = TRUE
PROPRULE_INVALID	propagation was applied without a specific propagation rule
PROPRULE_1	left hand side and bounds on y -> lower bound on x
PROPRULE_2	left hand side and upper bound on x -> bound on y
PROPRULE_3	right hand side and bounds on y -> upper bound on x
PROPRULE_4	right hand side and lower bound on x -> bound on y
PROPRULE_0	all variables are fixed => fix integral variable
PROPRULE_1	all except one variable fixed => fix remaining variable
PROPRULE_INTLB	lower bound propagation of integral variable
PROPRULE_INTUB	upper bound propagation of integral variable
PROPRULE_INVALID	propagation was applied without a specific propagation rule

Definition at line 330 of file cons_linear.c.

Function Documentation

static INFERINFO intToInferInfo ( int i )

static

converts an integer into an inference information

Parameters

i	integer to convert

Definition at line 359 of file cons_linear.c.

References inferInfoGetProprule().

static int inferInfoToInt ( INFERINFO inferinfo )

static

converts an inference information into an int

Parameters

inferinfo inference information to convert

Definition at line 372 of file cons_linear.c.

Referenced by getInferInfo().

static int inferInfoGetProprule ( INFERINFO inferinfo )

static

returns the propagation rule stored in the inference information

Parameters

inferinfo inference information to convert

Definition at line 381 of file cons_linear.c.

Referenced by intToInferInfo().

static int inferInfoGetPos ( INFERINFO inferinfo )

static

returns the position stored in the inference information

Parameters

inferinfo inference information to convert

Definition at line 390 of file cons_linear.c.

static INFERINFO getInferInfo	(	PROPRULE	proprule,
		int	pos
	)

static

constructs an inference information out of a propagation rule and a position number

Parameters

proprule	propagation rule that deduced the value
pos	variable position, the propagation rule was applied at

Definition at line 399 of file cons_linear.c.

References conshdlrdataEnsureLinconsupgradesSize(), and inferInfoToInt().

static int getInferInt	(	PROPRULE	proprule,
		int	pos
	)

static

constructs an inference information out of a propagation rule and a position number, returns info as int

Parameters

proprule	propagation rule that deduced the value
pos	variable position, the propagation rule was applied at

Definition at line 418 of file cons_linear.c.

References NULL, SCIP_CALL, SCIPcalcMemGrowSize(), and SCIPreallocMemoryArray.

static SCIP_RETCODE conshdlrdataEnsureLinconsupgradesSize	(	SCIP *	scip,
		SCIP_CONSHDLRDATA *	conshdlrdata,
		int	num
	)

static

ensures, that linconsupgrades array can store at least num entries

Parameters

scip	SCIP data structure
conshdlrdata	linear constraint handler data
num	minimum number of entries to store

Definition at line 433 of file cons_linear.c.

Referenced by conshdlrdataHasUpgrade(), and getInferInfo().

static SCIP_RETCODE consdataEnsureVarsSize	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata,
		int	num
	)

static

ensures, that vars and vals arrays can store at least num entries

Parameters

scip	SCIP data structure
consdata	linear constraint data
num	minimum number of entries to store

Definition at line 458 of file cons_linear.c.

static SCIP_RETCODE linconsupgradeCreate	(	SCIP *	scip,
		SCIP_LINCONSUPGRADE **	linconsupgrade,
		SCIP_DECL_LINCONSUPGD((*linconsupgd))	,
		int	priority
	)

static

creates a linear constraint upgrade data object

Parameters

scip	SCIP data structure
linconsupgrade	pointer to store the linear constraint upgrade
priority	priority of upgrading method

Definition at line 493 of file cons_linear.c.

References conshdlrdataCreate(), NULL, and SCIPfreeMemory.

static void linconsupgradeFree	(	SCIP *	scip,
		SCIP_LINCONSUPGRADE **	linconsupgrade
	)

static

frees a linear constraint upgrade data object

Parameters

scip	SCIP data structure
linconsupgrade	pointer to the linear constraint upgrade

Definition at line 514 of file cons_linear.c.

References NULL, SCIP_CALL, and SCIPallocMemory.

Referenced by conshdlrdataCreate().

static SCIP_RETCODE conshdlrdataCreate	(	SCIP *	scip,
		SCIP_CONSHDLRDATA **	conshdlrdata,
		SCIP_EVENTHDLR *	eventhdlr
	)

static

creates constraint handler data for linear constraint handler

Parameters

scip	SCIP data structure
conshdlrdata	pointer to store the constraint handler data
eventhdlr	event handler

Definition at line 528 of file cons_linear.c.

References linconsupgradeFree(), NULL, and SCIPfreeMemoryArrayNull.

Referenced by linconsupgradeCreate().

static void conshdlrdataFree	(	SCIP *	scip,
		SCIP_CONSHDLRDATA **	conshdlrdata
	)

static

frees constraint handler data for linear constraint handler

Parameters

scip	SCIP data structure
conshdlrdata	pointer to the constraint handler data

Definition at line 552 of file cons_linear.c.

Referenced by SCIP_DECL_CONSHDLRCOPY().

static SCIP_Bool conshdlrdataHasUpgrade	(	SCIP *	scip,
		SCIP_CONSHDLRDATA *	conshdlrdata,
		SCIP_DECL_LINCONSUPGD((*linconsupgd))	,
		const char *	conshdlrname
	)

static

creates a linear constraint upgrade data object

Parameters

scip	SCIP data structure
conshdlrdata	constraint handler data
conshdlrname	name of the constraint handler

Definition at line 574 of file cons_linear.c.

References conshdlrdataEnsureLinconsupgradesSize(), conshdlrdataIncludeUpgrade(), FALSE, NULL, SCIP_LinConsUpgrade::priority, SCIP_CALL, SCIPwarningMessage(), and TRUE.

static SCIP_RETCODE conshdlrdataIncludeUpgrade	(	SCIP *	scip,
		SCIP_CONSHDLRDATA *	conshdlrdata,
		SCIP_LINCONSUPGRADE *	linconsupgrade
	)

static

adds a linear constraint update method to the constraint handler's data

Parameters

scip	SCIP data structure
conshdlrdata	constraint handler data
linconsupgrade	linear constraint upgrade method

Definition at line 604 of file cons_linear.c.

References lockRounding(), NULL, SCIP_OKAY, SCIP_Real, SCIPconsGetData(), and SCIPisZero().

Referenced by conshdlrdataHasUpgrade().

static SCIP_RETCODE lockRounding	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_VAR *	var,
		SCIP_Real	val
	)

static

installs rounding locks for the given variable associated to the given coefficient in the linear constraint

Parameters

scip	SCIP data structure
cons	linear constraint
var	variable of constraint entry
val	coefficient of constraint entry

Definition at line 636 of file cons_linear.c.

References NULL, SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIPconsGetData(), SCIPisInfinity(), SCIPisZero(), SCIPlockVarCons(), and unlockRounding().

Referenced by conshdlrdataIncludeUpgrade().

static SCIP_RETCODE unlockRounding	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_VAR *	var,
		SCIP_Real	val
	)

static

removes rounding locks for the given variable associated to the given coefficient in the linear constraint

Parameters

scip	SCIP data structure
cons	linear constraint
var	variable of constraint entry
val	coefficient of constraint entry

Definition at line 669 of file cons_linear.c.

References consCatchEvent(), NULL, SCIP_CALL, SCIP_OKAY, SCIPconsGetData(), SCIPisInfinity(), and SCIPunlockVarCons().

Referenced by lockRounding().

static SCIP_RETCODE consCatchEvent	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_EVENTHDLR *	eventhdlr,
		int	pos
	)

static

creates event data for variable at given position, and catches events

Parameters

scip	SCIP data structure
cons	linear constraint
eventhdlr	event handler to call for the event processing
pos	array position of variable to catch bound change events for

Definition at line 702 of file cons_linear.c.

Referenced by unlockRounding().

static SCIP_RETCODE consDropEvent	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_EVENTHDLR *	eventhdlr,
		int	pos
	)

static

deletes event data for variable at given position, and drops events

Parameters

scip	SCIP data structure
cons	linear constraint
eventhdlr	event handler to call for the event processing
pos	array position of variable to catch bound change events for

Definition at line 738 of file cons_linear.c.

Referenced by consDropAllEvents().

static SCIP_RETCODE consCatchAllEvents	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_EVENTHDLR *	eventhdlr
	)

static

catches bound change events for all variables in transformed linear constraint

Parameters

scip	SCIP data structure
cons	linear constraint
eventhdlr	event handler to call for the event processing

Definition at line 772 of file cons_linear.c.

Referenced by SCIPcreateConsLinear().

static SCIP_RETCODE consDropAllEvents	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_EVENTHDLR *	eventhdlr
	)

static

drops bound change events for all variables in transformed linear constraint

Parameters

scip	SCIP data structure
cons	linear constraint
eventhdlr	event handler to call for the event processing

Definition at line 804 of file cons_linear.c.

References consdataCreate(), consDropEvent(), needEvents(), NULL, SCIP_Bool, SCIP_CALL, SCIP_OKAY, SCIP_STAGE_FREETRANS, SCIP_STAGE_TRANSFORMED, SCIPfreeBlockMemoryArray, and SCIPgetStage().

static SCIP_Bool needEvents ( SCIP * scip )

static

returns whether we are in a stage, where the variable events should be caught

Parameters

scip	SCIP data structure

Definition at line 835 of file cons_linear.c.

References NULL.

Referenced by consDropAllEvents(), and SCIPcreateConsLinear().

static SCIP_RETCODE consdataCreate	(	SCIP *	scip,
		SCIP_CONSDATA **	consdata,
		int	nvars,
		SCIP_VAR **	vars,
		SCIP_Real *	vals,
		SCIP_Real	lhs,
		SCIP_Real	rhs
	)

static

creates a linear constraint data

Parameters

scip	SCIP data structure
consdata	pointer to linear constraint data
nvars	number of nonzeros in the constraint
vars	array with variables of constraint entries
vals	array with coefficients of constraint entries
lhs	left hand side of row
rhs	right hand side of row

Definition at line 846 of file cons_linear.c.

Referenced by consDropAllEvents(), and SCIPcreateConsLinear().

static SCIP_RETCODE consdataFree	(	SCIP *	scip,
		SCIP_CONSDATA **	consdata
	)

static

frees a linear constraint data

Parameters

scip	SCIP data structure
consdata	pointer to linear constraint data

Definition at line 1001 of file cons_linear.c.

References consdataPrint(), NULL, SCIP_CALL, SCIP_OKAY, SCIPfreeBlockMemory, SCIPfreeBlockMemoryArrayNull, SCIPinfoMessage(), SCIPisEQ(), SCIPisInfinity(), SCIPisZero(), and SCIPreleaseVar().

static SCIP_RETCODE consdataPrint	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata,
		FILE *	file
	)

static

prints linear constraint in CIP format to file stream

Parameters

scip	SCIP data structure
consdata	linear constraint data
file	output file (or NULL for standard output)

Definition at line 1036 of file cons_linear.c.

Referenced by consdataFree(), and SCIP_DECL_CONSDELVARS().

static void consdataInvalidateActivities ( SCIP_CONSDATA * consdata )

static

invalidates activity bounds, such that they are recalculated in next get

Parameters

consdata linear constraint

Definition at line 1075 of file cons_linear.c.

References SCIP_Real.

static SCIP_Real consdataComputePseudoActivity	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata
	)

static

compute the pseudo activity of a constraint

Parameters

scip	SCIP data structure
consdata	linear constraint data

Definition at line 1119 of file cons_linear.c.

References consdataRecomputeMinactivity(), SCIP_BOUNDTYPE_LOWER, SCIP_INVALID, SCIP_Real, SCIPinfinity(), SCIPisHugeValue(), SCIPisInfinity(), SCIPvarGetBestBoundType(), SCIPvarGetLbLocal(), and SCIPvarGetUbLocal().

Referenced by consdataGetGlbActivityResiduals().

static void consdataRecomputeMinactivity	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata
	)

static

recompute the minactivity of a constraint

Parameters

scip	SCIP data structure
consdata	linear constraint data

Definition at line 1172 of file cons_linear.c.

References SCIP_Real, SCIPisHugeValue(), SCIPisInfinity(), SCIPvarGetLbLocal(), and SCIPvarGetUbLocal().

Referenced by consdataComputePseudoActivity(), and getMinActivity().

static void consdataRecomputeMaxactivity	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata
	)

static

recompute the maxactivity of a constraint

Parameters

scip	SCIP data structure
consdata	linear constraint data

Definition at line 1199 of file cons_linear.c.

References SCIP_Real, SCIPisInfinity(), SCIPvarGetLbGlobal(), and SCIPvarGetUbGlobal().

Referenced by getMaxActivity().

static void consdataRecomputeGlbMinactivity	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata
	)

static

recompute the global minactivity of a constraint

Parameters

scip	SCIP data structure
consdata	linear constraint data

Definition at line 1226 of file cons_linear.c.

References SCIP_Real, SCIPisInfinity(), SCIPvarGetLbGlobal(), and SCIPvarGetUbGlobal().

Referenced by getMinActivity().

static void consdataRecomputeGlbMaxactivity	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata
	)

static

recompute the global maxactivity of a constraint

Parameters

scip	SCIP data structure
consdata	linear constraint data

Definition at line 1252 of file cons_linear.c.

References NULL, SCIP_INVALID, SCIP_Real, and TRUE.

Referenced by getMaxActivity().

static void consdataCalcMaxAbsval ( SCIP_CONSDATA * consdata )

static

calculates maximum absolute value of coefficients

Parameters

consdata linear constraint data

Definition at line 1278 of file cons_linear.c.

static void consdataCheckNonbinvar ( SCIP_CONSDATA * consdata )

static

checks the type of all variables of the constraint and sets hasnonbinvar and hascontvar flags accordingly

Parameters

consdata linear constraint data

Definition at line 1302 of file cons_linear.c.

References checkMaxActivityDelta, consdataRecomputeMaxActivityDelta(), REALABS, SCIP_INVALID, SCIP_Real, SCIPinfinity(), SCIPisFeasEQ(), SCIPisInfinity(), SCIPvarGetLbLocal(), SCIPvarGetUbLocal(), and TRUE.

static void consdataRecomputeMaxActivityDelta	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata
	)

static

recompute maximal activity contribution for a single variable

Parameters

scip	SCIP data structure
consdata	linear constraint data

Definition at line 1378 of file cons_linear.c.

References consdataUpdateActivities(), REALABS, SCIP_Bool, SCIP_Real, SCIPinfinity(), SCIPisInfinity(), SCIPvarGetLbLocal(), and SCIPvarGetUbLocal().

Referenced by consdataCheckNonbinvar().

static void consdataUpdateActivities	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata,
		SCIP_VAR *	var,
		SCIP_Real	oldbound,
		SCIP_Real	newbound,
		SCIP_Real	val,
		SCIP_BOUNDTYPE	boundtype,
		SCIP_Bool	global,
		SCIP_Bool	checkreliability
	)

static

updates activities for a change in a bound

Parameters

scip	SCIP data structure
consdata	linear constraint data
var	variable that has been changed; can be NULL for global bound changes
oldbound	old bound of variable
newbound	new bound of variable
val	coefficient of constraint entry
boundtype	type of the bound change
global	is it a global or a local bound change?
checkreliability	should the reliability of the recalculated activity be checked?

Definition at line 1440 of file cons_linear.c.

Referenced by consdataRecomputeMaxActivityDelta().

static void consdataUpdateActivitiesLb	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata,
		SCIP_VAR *	var,
		SCIP_Real	oldlb,
		SCIP_Real	newlb,
		SCIP_Real	val,
		SCIP_Bool	checkreliability
	)

static

updates minimum and maximum activity for a change in lower bound

Parameters

scip	SCIP data structure
consdata	linear constraint data
var	variable that has been changed
oldlb	old lower bound of variable
newlb	new lower bound of variable
val	coefficient of constraint entry
checkreliability	should the reliability of the recalculated activity be checked?

Definition at line 1798 of file cons_linear.c.

static void consdataUpdateActivitiesUb	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata,
		SCIP_VAR *	var,
		SCIP_Real	oldub,
		SCIP_Real	newub,
		SCIP_Real	val,
		SCIP_Bool	checkreliability
	)

static

updates minimum and maximum activity for a change in upper bound

Parameters

scip	SCIP data structure
consdata	linear constraint data
var	variable that has been changed
oldub	old upper bound of variable
newub	new upper bound of variable
val	coefficient of constraint entry
checkreliability	should the reliability of the recalculated activity be checked?

Definition at line 1823 of file cons_linear.c.

static void consdataUpdateActivitiesGlbLb	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata,
		SCIP_Real	oldlb,
		SCIP_Real	newlb,
		SCIP_Real	val,
		SCIP_Bool	checkreliability
	)

static

updates minimum and maximum global activity for a change in the global lower bound

Parameters

scip	SCIP data structure
consdata	linear constraint data
oldlb	old lower bound of variable
newlb	new lower bound of variable
val	coefficient of constraint entry
checkreliability	should the reliability of the recalculated activity be checked?

Definition at line 1848 of file cons_linear.c.

static void consdataUpdateActivitiesGlbUb	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata,
		SCIP_Real	oldub,
		SCIP_Real	newub,
		SCIP_Real	val,
		SCIP_Bool	checkreliability
	)

static

updates minimum and maximum global activity for a change in global upper bound

Parameters

scip	SCIP data structure
consdata	linear constraint data
oldub	old upper bound of variable
newub	new upper bound of variable
val	coefficient of constraint entry
checkreliability	should the reliability of the recalculated activity be checked?

Definition at line 1871 of file cons_linear.c.

static void consdataUpdateAddCoef	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata,
		SCIP_VAR *	var,
		SCIP_Real	val,
		SCIP_Bool	checkreliability
	)

static

updates minimum and maximum activity and maximum absolute value for coefficient addition

Parameters

scip	SCIP data structure
consdata	linear constraint data
var	variable of constraint entry
val	coefficient of constraint entry
checkreliability	should the reliability of the recalculated activity be checked?

Definition at line 1894 of file cons_linear.c.

static void consdataUpdateDelCoef	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata,
		SCIP_VAR *	var,
		SCIP_Real	val,
		SCIP_Bool	checkreliability
	)

static

updates minimum and maximum activity for coefficient deletion, invalidates maximum absolute value if necessary

Parameters

scip	SCIP data structure
consdata	linear constraint data
var	variable of constraint entry
val	coefficient of constraint entry
checkreliability	should the reliability of the recalculated activity be checked?

Definition at line 1934 of file cons_linear.c.

static void consdataUpdateChgCoef	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata,
		SCIP_VAR *	var,
		SCIP_Real	oldval,
		SCIP_Real	newval,
		SCIP_Bool	checkreliability
	)

static

updates minimum and maximum activity for coefficient change, invalidates maximum absolute value if necessary

Parameters

scip	SCIP data structure
consdata	linear constraint data
var	variable of constraint entry
oldval	old coefficient of constraint entry
newval	new coefficient of constraint entry
checkreliability	should the reliability of the recalculated activity be checked?

Definition at line 1977 of file cons_linear.c.

static SCIP_Real consdataGetMaxAbsval ( SCIP_CONSDATA * consdata )

static

returns the maximum absolute value of all coefficients in the constraint

Parameters

consdata linear constraint data

Definition at line 2052 of file cons_linear.c.

References NULL, SCIP_INVALID, and TRUE.

Referenced by aggregateConstraints().

static void consdataCalcActivities	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata
	)

static

calculates minimum and maximum local and global activity for constraint from scratch; additionally recalculates maximum absolute value of coefficients

Parameters

scip	SCIP data structure
consdata	linear constraint data

Definition at line 2070 of file cons_linear.c.

Referenced by consdataGetActivityResiduals(), consdataGetGlbActivityBounds(), and consdataGetGlbActivityResiduals().

static void getMinActivity	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata,
		int	posinf,
		int	neginf,
		int	poshuge,
		int	neghuge,
		SCIP_Real	delta,
		SCIP_Bool	global,
		SCIP_Bool	goodrelax,
		SCIP_Real *	minactivity,
		SCIP_Bool *	isrelax,
		SCIP_Bool *	issettoinfinity
	)

static

gets minimal activity for constraint and given values of counters for infinite and huge contributions and (if needed) delta to subtract from stored finite part of activity in case of a residual activity

Parameters

scip	SCIP data structure
consdata	linear constraint
posinf	number of coefficients contributing pos. infinite value
neginf	number of coefficients contributing neg. infinite value
poshuge	number of coefficients contributing huge pos. value
neghuge	number of coefficients contributing huge neg. value
delta	value to subtract from stored minactivity (contribution of the variable set to zero when getting residual activity)
global	should the global or local minimal activity be returned?
goodrelax	should a good relaxation be computed or are relaxed acticities ignored, anyway?
minactivity	pointer to store the minimal activity
isrelax	pointer to store whether the activity is a relaxation, i.e. is <= the exact minactivity (in case of huge contributing values)
issettoinfinity	pointer to store whether minactivity was set to infinity or calculated

Definition at line 2130 of file cons_linear.c.

References consdataRecomputeGlbMinactivity(), consdataRecomputeMinactivity(), FALSE, getMaxActivity(), NULL, SCIP_Bool, SCIP_Real, SCIPgetHugeValue(), SCIPinfinity(), and TRUE.

Referenced by consdataGetActivityResiduals(), consdataGetGlbActivityBounds(), and consdataGetGlbActivityResiduals().

static void getMaxActivity	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata,
		int	posinf,
		int	neginf,
		int	poshuge,
		int	neghuge,
		SCIP_Real	delta,
		SCIP_Bool	global,
		SCIP_Bool	goodrelax,
		SCIP_Real *	maxactivity,
		SCIP_Bool *	isrelax,
		SCIP_Bool *	issettoinfinity
	)

static

gets maximal activity for constraint and given values of counters for infinite and huge contributions and (if needed) delta to subtract from stored finite part of activity in case of a residual activity

Parameters

scip	SCIP data structure
consdata	linear constraint
posinf	number of coefficients contributing pos. infinite value
neginf	number of coefficients contributing neg. infinite value
poshuge	number of coefficients contributing huge pos. value
neghuge	number of coefficients contributing huge neg. value
delta	value to subtract from stored maxactivity (contribution of the variable set to zero when getting residual activity)
global	should the global or local maximal activity be returned?
goodrelax	should a good relaxation be computed or are relaxed acticities ignored, anyway?
maxactivity	pointer to store the maximal activity
isrelax	pointer to store whether the activity is a relaxation, i.e. is >= the exact maxactivity (in case of huge contributing values)
issettoinfinity	pointer to store whether maxactivity was set to infinity or calculated

Definition at line 2231 of file cons_linear.c.

References consdataGetActivityBounds(), consdataRecomputeGlbMaxactivity(), consdataRecomputeMaxactivity(), FALSE, NULL, SCIP_Bool, SCIP_Real, SCIPgetHugeValue(), SCIPinfinity(), and TRUE.

Referenced by consdataGetActivityResiduals(), consdataGetGlbActivityBounds(), consdataGetGlbActivityResiduals(), and getMinActivity().

static void consdataGetActivityBounds	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata,
		SCIP_Bool	goodrelax,
		SCIP_Real *	minactivity,
		SCIP_Real *	maxactivity,
		SCIP_Bool *	minisrelax,
		SCIP_Bool *	maxisrelax
	)

static

gets activity bounds for constraint

Parameters

scip	SCIP data structure
consdata	linear constraint
goodrelax	if we have huge contributions, do we need a good relaxation or are relaxed acticities ignored, anyway?
minactivity	pointer to store the minimal activity
maxactivity	pointer to store the maximal activity
minisrelax	pointer to store whether the returned minactivity is just a relaxation, i.e. <= the exact minactivity (in case of huge contributions), or equal to the exact minimal activity
maxisrelax	pointer to store whether the returned maxactivity is just a relaxation, i.e. >= the exact maxactivity (in case of huge contributions), or equal to the exact maximal activity

Definition at line 2330 of file cons_linear.c.

Referenced by getMaxActivity().

static void consdataGetReliableResidualActivity	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata,
		SCIP_VAR *	cancelvar,
		SCIP_Real *	resactivity,
		SCIP_Bool	isminresact,
		SCIP_Bool	useglobalbounds
	)

static

calculates activity bounds for constraint after setting variable to zero

Parameters

scip	SCIP data structure
consdata	linear constraint
cancelvar	variable to calculate activity residual for
resactivity	pointer to store the residual activity
isminresact	should minimal or maximal residual activity be calculated?
useglobalbounds	should global or local bounds be used?

Definition at line 2376 of file cons_linear.c.

static void consdataGetActivityResiduals	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata,
		SCIP_VAR *	var,
		SCIP_Real	val,
		SCIP_Bool	goodrelax,
		SCIP_Real *	minresactivity,
		SCIP_Real *	maxresactivity,
		SCIP_Bool *	minisrelax,
		SCIP_Bool *	maxisrelax,
		SCIP_Bool *	isminsettoinfinity,
		SCIP_Bool *	ismaxsettoinfinity
	)

static

gets activity bounds for constraint after setting variable to zero

Parameters

scip	SCIP data structure
consdata	linear constraint
var	variable to calculate activity residual for
val	coefficient value of variable in linear constraint
goodrelax	if we have huge contributions, do we need a good relaxation or are relaxed acticities ignored, anyway?
minresactivity	pointer to store the minimal residual activity
maxresactivity	pointer to store the maximal residual activity
minisrelax	pointer to store whether the returned residual minactivity is just a relaxation, i.e. <= the exact residual minactivity (in case of huge contributions), or equal to the exact residual minactivity
maxisrelax	pointer to store whether the returned residual maxactivity is just a relaxation, i.e. <= the exact residual maxactivity (in case of huge contributions), or equal to the exact residual minactivity
isminsettoinfinity	pointer to store whether minresactivity was set to infinity or calculated
ismaxsettoinfinity	pointer to store whether maxresactivity was set to infinity or calculated

Definition at line 2457 of file cons_linear.c.

References consdataCalcActivities(), consdataGetGlbActivityBounds(), FALSE, getMaxActivity(), getMinActivity(), NULL, SCIP_Bool, SCIP_INVALID, SCIP_Real, SCIPisHugeValue(), SCIPisInfinity(), SCIPvarGetLbLocal(), and SCIPvarGetUbLocal().

static void consdataGetGlbActivityBounds	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata,
		SCIP_Bool	goodrelax,
		SCIP_Real *	glbminactivity,
		SCIP_Real *	glbmaxactivity,
		SCIP_Bool *	minisrelax,
		SCIP_Bool *	maxisrelax,
		SCIP_Bool *	isminsettoinfinity,
		SCIP_Bool *	ismaxsettoinfinity
	)

static

gets global activity bounds for constraint

Parameters

scip	SCIP data structure
consdata	linear constraint
goodrelax	if we have huge contributions, do we need a good relaxation or are relaxed acticities ignored, anyway?
glbminactivity	pointer to store the minimal activity, or NULL, if not needed
glbmaxactivity	pointer to store the maximal activity, or NULL, if not needed
minisrelax	pointer to store whether the returned minactivity is just a relaxation, i.e. <= the exact minactivity (in case of huge contributions), or equal to the exact minimal activity
maxisrelax	pointer to store whether the returned maxactivity is just a relaxation, i.e. >= the exact maxactivity (in case of huge contributions), or equal to the exact maximal activity
isminsettoinfinity	pointer to store whether minresactivity was set to infinity or calculated
ismaxsettoinfinity	pointer to store whether maxresactivity was set to infinity or calculated

Definition at line 2608 of file cons_linear.c.

References consdataCalcActivities(), consdataGetGlbActivityResiduals(), getMaxActivity(), getMinActivity(), NULL, SCIP_Bool, SCIP_INVALID, SCIP_Real, and TRUE.

Referenced by consdataGetActivityResiduals().

static void consdataGetGlbActivityResiduals	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata,
		SCIP_VAR *	var,
		SCIP_Real	val,
		SCIP_Bool	goodrelax,
		SCIP_Real *	minresactivity,
		SCIP_Real *	maxresactivity,
		SCIP_Bool *	minisrelax,
		SCIP_Bool *	maxisrelax,
		SCIP_Bool *	isminsettoinfinity,
		SCIP_Bool *	ismaxsettoinfinity
	)

static

gets global activity bounds for constraint after setting variable to zero

Parameters

scip	SCIP data structure
consdata	linear constraint
var	variable to calculate activity residual for
val	coefficient value of variable in linear constraint
goodrelax	if we have huge contributions, do we need a good relaxation or are relaxed acticities ignored, anyway?
minresactivity	pointer to store the minimal residual activity, or NULL, if not needed
maxresactivity	pointer to store the maximal residual activity, or NULL, if not needed
minisrelax	pointer to store whether the returned residual minactivity is just a relaxation, i.e. <= the exact residual minactivity (in case of huge contributions), or equal to the exact residual minactivity
maxisrelax	pointer to store whether the returned residual maxactivity is just a relaxation, i.e. <= the exact residual maxactivity (in case of huge contributions), or equal to the exact residual minactivity
isminsettoinfinity	pointer to store whether minresactivity was set to infinity or calculated
ismaxsettoinfinity	pointer to store whether maxresactivity was set to infinity or calculated

Definition at line 2670 of file cons_linear.c.

References consdataCalcActivities(), consdataComputePseudoActivity(), consdataGetActivity(), getMaxActivity(), getMinActivity(), NULL, SCIP_INVALID, SCIP_Real, SCIPhasCurrentNodeLP(), SCIPisHugeValue(), SCIPisInfinity(), SCIPvarGetLbGlobal(), SCIPvarGetUbGlobal(), and TRUE.

Referenced by consdataGetGlbActivityBounds().

static SCIP_Real consdataGetActivity	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata,
		SCIP_SOL *	sol
	)

static

calculates the activity of the linear constraint for given solution

Parameters

scip	SCIP data structure
consdata	linear constraint data
sol	solution to get activity for, NULL to current solution

Definition at line 2822 of file cons_linear.c.

References consdataGetFeasibility(), FALSE, MAX, MIN, NULL, SCIP_INVALID, SCIP_Real, SCIPdebugMessage, SCIPgetSolVal(), SCIPinfinity(), SCIPisInfinity(), and TRUE.

Referenced by consdataGetGlbActivityResiduals(), and SCIP_DECL_CONSCHECK().

static SCIP_Real consdataGetFeasibility	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata,
		SCIP_SOL *	sol
	)

static

calculates the feasibility of the linear constraint for given solution

Parameters

scip	SCIP data structure
consdata	linear constraint data
sol	solution to get feasibility for, NULL to current solution

Definition at line 2891 of file cons_linear.c.

Referenced by consdataGetActivity().

static SCIP_Longint getVarSignature ( SCIP_VAR * var )

static

returns the signature bitmask for the given variable

Parameters

var variable

Definition at line 2912 of file cons_linear.c.

References NULL, SCIP_Longint, SCIP_Real, SCIPvarGetLbGlobal(), and SCIPvarGetUbGlobal().

static void consdataUpdateSignatures	(	SCIP_CONSDATA *	consdata,
		int	pos
	)

static

updates bit signatures after adding a single coefficient

Parameters

consdata	linear constraint data
pos	position of coefficient to update signatures for

Definition at line 2926 of file cons_linear.c.

References NULL, and TRUE.

static void consdataCalcSignatures ( SCIP_CONSDATA * consdata )

static

calculates the bit signatures of the given constraint data

Parameters

consdata linear constraint data

Definition at line 2951 of file cons_linear.c.

References NULL, permSortConsdata(), and SCIPvarCompare().

static SCIP_DECL_SORTINDCOMP ( consdataCompVar )

static

index comparison method of linear constraints: compares two indices of the variable set in the linear constraint

Definition at line 2971 of file cons_linear.c.

References NULL, and SCIP_Real.

static void permSortConsdata	(	SCIP_CONSDATA *	consdata,
		int *	perm,
		int	nvars
	)

static

permutes the constraint's variables according to a given permutation.

Parameters

consdata	the constraint data
perm	the target permutation
nvars	the number of variables

Definition at line 2984 of file cons_linear.c.

References consdataSort(), NULL, SCIP_STAGE_INITSOLVE, SCIPgetStage(), and TRUE.

Referenced by consdataCalcSignatures().

static SCIP_RETCODE consdataSort	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata
	)

static

sorts linear constraint's variables depending on the stage of the solving process:

during PRESOLVING sorts variables by binaries, integers, implicit integers, and continuous variables, and the variables of the same type by non-decreasing variable index
during SOLVING sorts binary variables of the remaining problem w.r.t the absolute of their coefficient. This fastens the propagation time of the constraint handler.

Parameters

scip	SCIP data structure
consdata	linear constraint data

Definition at line 3057 of file cons_linear.c.

Referenced by permSortConsdata().

static SCIP_RETCODE chgLhs	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_Real	lhs
	)

static

sets left hand side of linear constraint

Parameters

scip	SCIP data structure
cons	linear constraint
lhs	new left hand side

Definition at line 3205 of file cons_linear.c.

Referenced by SCIPaddCoefLinear(), and tightenSides().

static SCIP_RETCODE chgRhs	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_Real	rhs
	)

static

sets right hand side of linear constraint

Parameters

scip	SCIP data structure
cons	linear constraint
rhs	new right hand side

Definition at line 3320 of file cons_linear.c.

Referenced by SCIPaddCoefLinear(), SCIPchgLhsLinear(), and tightenSides().

static SCIP_RETCODE addCoef	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_VAR *	var,
		SCIP_Real	val
	)

static

adds coefficient in linear constraint

Parameters

scip	SCIP data structure
cons	linear constraint
var	variable of constraint entry
val	coefficient of constraint entry

Definition at line 3437 of file cons_linear.c.

Referenced by SCIPaddCoefLinear().

static SCIP_RETCODE delCoefPos	(	SCIP *	scip,
		SCIP_CONS *	cons,
		int	pos
	)

static

deletes coefficient at given position from linear constraint data

Parameters

scip	SCIP data structure
cons	linear constraint
pos	position of coefficient to delete

Definition at line 3585 of file cons_linear.c.

Referenced by performVarDeletions(), and SCIPchgCoefLinear().

static SCIP_RETCODE chgCoefPos	(	SCIP *	scip,
		SCIP_CONS *	cons,
		int	pos,
		SCIP_Real	newval
	)

static

changes coefficient value at given position of linear constraint data

Parameters

scip	SCIP data structure
cons	linear constraint
pos	position of coefficient to delete
newval	new value of coefficient

Definition at line 3701 of file cons_linear.c.

Referenced by SCIPchgCoefLinear().

static SCIP_RETCODE scaleCons	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_Real	scalar
	)

static

scales a linear constraint with a constant scalar

Parameters

scip	SCIP data structure
cons	linear constraint to scale
scalar	value to scale constraint with

Definition at line 3763 of file cons_linear.c.

static SCIP_RETCODE performVarDeletions	(	SCIP *	scip,
		SCIP_CONSHDLR *	conshdlr,
		SCIP_CONS **	conss,
		int	nconss
	)

static

Parameters

scip	SCIP data structure
conshdlr	constraint handler
conss	array of constraints
nconss	number of constraints

Definition at line 3847 of file cons_linear.c.

References delCoefPos(), FALSE, normalizeCons(), SCIP_CALL, SCIP_Longint, SCIP_OKAY, SCIP_Real, SCIPconsGetData(), and SCIPvarIsDeleted().

Referenced by SCIP_DECL_CONSLOCK().

static SCIP_RETCODE normalizeCons	(	SCIP *	scip,
		SCIP_CONS *	cons
	)

static

normalizes a linear constraint with the following rules:

if all coefficients have them same absolute value, change them to (-)1.0
multiplication with +1 or -1: Apply the following rules in the given order, until the sign of the factor is determined. Later rules only apply, if the current rule doesn't determine the sign):
1. the right hand side must not be negative
2. the right hand side must not be infinite
3. the absolute value of the right hand side must be greater than that of the left hand side
4. the number of positive coefficients must not be smaller than the number of negative coefficients
5. multiply with +1
rationals to integrals Try to identify a rational representation of the fractional coefficients, and multiply all coefficients by the smallest common multiple of all denominators to get integral coefficients. Forbid large denominators due to numerical stability.
division by greatest common divisor If all coefficients are integral, divide them by the greatest common divisor.

Parameters

scip	SCIP data structure
cons	linear constraint to normalize

Definition at line 3906 of file cons_linear.c.

Referenced by aggregateConstraints(), and performVarDeletions().

static SCIP_RETCODE mergeMultiples	(	SCIP *	scip,
		SCIP_CONS *	cons
	)

static

replaces multiple occurrences of a variable by a single coefficient

Parameters

scip	SCIP data structure
cons	linear constraint

Definition at line 4229 of file cons_linear.c.

static SCIP_RETCODE applyFixings	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_Bool *	infeasible
	)

static

replaces all fixed and aggregated variables by their non-fixed counterparts

Parameters

scip	SCIP data structure
cons	linear constraint
infeasible	pointer to store if infeasibility is detected; or NULL if this information is not needed; in this case, we apply all fixings instead of stopping after the first infeasible one

Definition at line 4300 of file cons_linear.c.

static SCIP_RETCODE addConflictBounds	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_VAR *	infervar,
		SCIP_BDCHGIDX *	bdchgidx,
		int	inferpos,
		SCIP_Bool	reasonisrhs
	)

static

for each variable in the linear constraint, except the inferred variable, adds one bound to the conflict analysis' candidate store (bound depends on sign of coefficient and whether the left or right hand side was the reason for the inference variable's bound change); the conflict analysis can be initialized with the linear constraint being the conflict detecting constraint by using NULL as inferred variable

Parameters

scip	SCIP data structure
cons	constraint that inferred the bound change
infervar	variable that was deduced, or NULL
bdchgidx	bound change index (time stamp of bound change), or NULL for current time
inferpos	position of the inferred variable in the vars array
reasonisrhs	is the right hand side responsible for the bound change?

Definition at line 4541 of file cons_linear.c.

static SCIP_RETCODE addConflictFixedVars	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_VAR *	infervar,
		SCIP_BDCHGIDX *	bdchgidx,
		int	inferpos
	)

static

for each variable in the linear ranged row constraint, except the inferred variable, adds the bounds of all fixed variables to the conflict analysis' candidate store; the conflict analysis can be initialized with the linear constraint being the conflict detecting constraint by using NULL as inferred variable

Parameters

scip	SCIP data structure
cons	constraint that inferred the bound change
infervar	variable that was deduced, or NULL
bdchgidx	bound change index (time stamp of bound change), or NULL for current time
inferpos	position of the inferred variable in the vars array, or -1

Definition at line 4720 of file cons_linear.c.

static SCIP_RETCODE addConflictReasonVars	(	SCIP *	scip,
		SCIP_VAR **	vars,
		int	nvars,
		SCIP_VAR *	var,
		SCIP_Real	bound
	)

static

add reasoning variables to conflict candidate queue which led to the conflict

Parameters

scip	SCIP data structure
vars	variables reasoning the infeasibility
nvars	number of variables reasoning the infeasibility
var	variable which was tried to fix/tighten, or NULL
bound	bound of variable which was tried to apply, or SCIP_INVALID

Definition at line 4784 of file cons_linear.c.

References NULL, resolvePropagation(), SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIPaddConflictLb(), SCIPaddConflictUb(), SCIPisEQ(), SCIPvarGetLbLocal(), SCIPvarGetUbGlobal(), and SCIPvarGetUbLocal().

static SCIP_RETCODE resolvePropagation	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_VAR *	infervar,
		INFERINFO	inferinfo,
		SCIP_BOUNDTYPE	boundtype,
		SCIP_BDCHGIDX *	bdchgidx,
		SCIP_RESULT *	result
	)

static

resolves a propagation on the given variable by supplying the variables needed for applying the corresponding propagation rule (see propagateCons()): (1) activity residuals of all other variables tighten bounds of single variable

Parameters

scip	SCIP data structure
cons	constraint that inferred the bound change
infervar	variable that was deduced
inferinfo	inference information
boundtype	the type of the changed bound (lower or upper bound)
bdchgidx	bound change index (time stamp of bound change), or NULL for current time
result	pointer to store the result of the propagation conflict resolving call

Definition at line 4835 of file cons_linear.c.

Referenced by addConflictReasonVars().

static SCIP_RETCODE analyzeConflict	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_Bool	reasonisrhs
	)

static

analyzes conflicting bounds on given constraint, and adds conflict constraint to problem

Parameters

scip	SCIP data structure
cons	conflict detecting constraint
reasonisrhs	is the right hand side responsible for the conflict?

Definition at line 4928 of file cons_linear.c.

static SCIP_Bool canTightenBounds	(	SCIP *	scip,
		SCIP_CONS *	cons
	)

static

check if there is any hope of tightening some bounds

Parameters

scip	SCIP data structure
cons	linear constraint

Definition at line 4952 of file cons_linear.c.

References SCIP_Bool, and SCIP_Real.

static SCIP_RETCODE tightenVarUb	(	SCIP *	scip,
		SCIP_CONS *	cons,
		int	pos,
		PROPRULE	proprule,
		SCIP_Real	newub,
		SCIP_Real	oldub,
		SCIP_Bool *	cutoff,
		int *	nchgbds,
		SCIP_Bool	force
	)

static

tighten upper bound

Parameters

scip	SCIP data structure
cons	linear constraint
pos	variable position
proprule	propagation rule that deduced the value
newub	new upper bound
oldub	old upper bound
cutoff	pointer to store whether the node can be cut off
nchgbds	pointer to count the total number of tightened bounds
force	should a possible bound change be forced even if below bound strengthening tolerance

Definition at line 4981 of file cons_linear.c.

static SCIP_RETCODE tightenVarLb	(	SCIP *	scip,
		SCIP_CONS *	cons,
		int	pos,
		PROPRULE	proprule,
		SCIP_Real	newlb,
		SCIP_Real	oldlb,
		SCIP_Bool *	cutoff,
		int *	nchgbds,
		SCIP_Bool	force
	)

static

tighten lower bound

Parameters

scip	SCIP data structure
cons	linear constraint
pos	variable position
proprule	propagation rule that deduced the value
newlb	new lower bound
oldlb	old lower bound
cutoff	pointer to store whether the node can be cut off
nchgbds	pointer to count the total number of tightened bounds
force	should a possible bound change be forced even if below bound strengthening tolerance

Definition at line 5050 of file cons_linear.c.

static SCIP_RETCODE tightenVarBoundsEasy	(	SCIP *	scip,
		SCIP_CONS *	cons,
		int	pos,
		SCIP_Bool *	cutoff,
		int *	nchgbds,
		SCIP_Bool	force
	)

static

tightens bounds of a single variable due to activity bounds (easy case)

Parameters

scip	SCIP data structure
cons	linear constraint
pos	position of the variable in the vars array
cutoff	pointer to store whether the node can be cut off
nchgbds	pointer to count the total number of tightened bounds
force	should a possible bound change be forced even if below bound strengthening tolerance

Definition at line 5119 of file cons_linear.c.

static SCIP_RETCODE analyzeConflictRangedRow	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_VAR **	vars,
		int	nvars,
		SCIP_VAR *	var,
		SCIP_Real	bound
	)

static

analyzes conflicting bounds on given ranged row constraint, and adds conflict constraint to problem

Parameters

scip	SCIP data structure
cons	conflict detecting constraint
vars	variables reasoning the infeasibility
nvars	number of variables reasoning the infeasibility
var	variable which was tried to fix/tighten, or NULL
bound	bound of variable which was tried to apply, or SCIP_INVALID

Definition at line 5379 of file cons_linear.c.

static SCIP_RETCODE rangedRowPropagation	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_Bool *	cutoff,
		int *	nfixedvars,
		int *	nchgbds,
		int *	naddconss
	)

static

propagate ranged rows

Check ranged rows for possible solutions, possibly detect infeasibility, fix variables due to having only one possible solution, tighten bounds if having only two possible solutions or add constraints which propagate a subset of variables better.

Example: c1: 12 x1 + 9 x2 - x3 = 0 with x1, x2 free and 1 <= x3 <= 2

x3 needs to be a multiple of 3, so the instance is infeasibile.

Example: c1: 12 x1 + 9 x2 - x3 = 1 with x1, x2 free and 1 <= x3 <= 2

The only posible value for x3 is 2, so the variable will be fixed.

Parameters

scip	SCIP data structure
cons	linear constraint
cutoff	pointer to store TRUE, if a cutoff was found
nfixedvars	pointer to count number of fixed variables
nchgbds	pointer to count the number of bound changes
naddconss	pointer to count number of added constraints

Definition at line 5437 of file cons_linear.c.

static SCIP_RETCODE tightenVarBounds	(	SCIP *	scip,
		SCIP_CONS *	cons,
		int	pos,
		SCIP_Bool *	cutoff,
		int *	nchgbds,
		SCIP_Bool	force
	)

static

tightens bounds of a single variable due to activity bounds

Parameters

scip	SCIP data structure
cons	linear constraint
pos	position of the variable in the vars array
cutoff	pointer to store whether the node can be cut off
nchgbds	pointer to count the total number of tightened bounds
force	should a possible bound change be forced even if below bound strengthening tolerance

Definition at line 6397 of file cons_linear.c.

static SCIP_RETCODE tightenBounds	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_Real	maxeasyactivitydelta,
		SCIP_Bool	sortvars,
		SCIP_Bool *	cutoff,
		int *	nchgbds
	)

static

tightens bounds of variables in constraint due to activity bounds

Parameters

scip	SCIP data structure
cons	linear constraint
maxeasyactivitydelta	maximum activity delta to run easy propagation on linear constraint
sortvars	should variables be used in sorted order?
cutoff	pointer to store whether the node can be cut off
nchgbds	pointer to count the total number of tightened bounds

Definition at line 6669 of file cons_linear.c.

static SCIP_RETCODE checkCons	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_SOL *	sol,
		SCIP_Bool	checklprows,
		SCIP_Bool	checkrelmaxabs,
		SCIP_Bool *	violated
	)

static

checks linear constraint for feasibility of given solution or current solution

Parameters

scip	SCIP data structure
cons	linear constraint
sol	solution to be checked, or NULL for current solution
checklprows	Do constraints represented by rows in the current LP have to be checked?
checkrelmaxabs	Should the violation for a constraint with side 0.0 be checked relative to 1.0 (FALSE) or to the maximum absolute value in the activity (TRUE)?
violated	pointer to store whether the constraint is violated

Definition at line 6810 of file cons_linear.c.

Referenced by SCIP_DECL_CONSCHECK(), and SCIP_DECL_CONSENFOLP().

static SCIP_RETCODE createRow	(	SCIP *	scip,
		SCIP_CONS *	cons
	)

static

creates an LP row in a linear constraint data

Parameters

scip	SCIP data structure
cons	linear constraint

Definition at line 7027 of file cons_linear.c.

Referenced by addRelaxation().

static SCIP_RETCODE addRelaxation	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_SOL *	sol,
		SCIP_Bool *	cutoff
	)

static

adds linear constraint as cut to the LP

Parameters

scip	SCIP data structure
cons	linear constraint
sol	primal CIP solution, NULL for current LP solution
cutoff	pointer to store whether a cutoff was found

Definition at line 7051 of file cons_linear.c.

References createRow(), FALSE, NULL, SCIP_Bool, SCIP_CALL, SCIP_OKAY, SCIPaddCut(), SCIPconsGetName(), SCIPdebug, SCIPdebugMessage, SCIPgetIntParam(), SCIPisInfinity(), SCIPprintRow(), SCIProwIsInLP(), and separateCons().

Referenced by SCIP_DECL_CONSENFOLP().

static SCIP_RETCODE separateCons	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_CONSHDLRDATA *	conshdlrdata,
		SCIP_SOL *	sol,
		SCIP_Bool	separatecards,
		SCIP_Bool	separateall,
		int *	ncuts,
		SCIP_Bool *	cutoff
	)

static

separates linear constraint: adds linear constraint as cut, if violated by given solution

Parameters

scip	SCIP data structure
cons	linear constraint
conshdlrdata	constraint handler data
sol	primal CIP solution, NULL for current LP solution
separatecards	should knapsack cardinality cuts be generated?
separateall	should all constraints be subject to cardinality cut generation instead of only the ones with non-zero dual value?
ncuts	pointer to add up the number of found cuts
cutoff	pointer to store whether a cutoff was found

Definition at line 7100 of file cons_linear.c.

Referenced by addRelaxation().

static SCIP_RETCODE propagateCons	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_Bool	tightenbounds,
		SCIP_Bool	rangedrowpropagation,
		SCIP_Real	maxeasyactivitydelta,
		SCIP_Bool	sortvars,
		SCIP_Bool *	cutoff,
		int *	nchgbds
	)

static

propagation method for linear constraints

Parameters

scip	SCIP data structure
cons	linear constraint
tightenbounds	should the variable's bounds be tightened?
rangedrowpropagation	should ranged row propagation be performed?
maxeasyactivitydelta	maximum activity delta to run easy propagation on linear constraint
sortvars	should variable sorting for faster propagation be used?
cutoff	pointer to store whether the node can be cut off
nchgbds	pointer to count the total number of tightened bounds

Definition at line 7190 of file cons_linear.c.

static SCIP_RETCODE fixVariables	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_Bool *	cutoff,
		int *	nfixedvars
	)

static

converts all variables with fixed domain into FIXED variables

Parameters

scip	SCIP data structure
cons	linear constraint
cutoff	pointer to store TRUE, if a cutoff was found
nfixedvars	pointer to count the total number of fixed variables

Definition at line 7322 of file cons_linear.c.

static SCIP_RETCODE extractCliques	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_Real	maxeasyactivitydelta,
		SCIP_Bool	sortvars,
		int *	nfixedvars,
		int *	nchgbds,
		SCIP_Bool *	cutoff
	)

static

extracts cliques of the constraint and adds them to SCIP

The following clique extraction mechanism are implemeneted

collect binary variables and sort them in non increasing order, then

a) if the constraint has a finite right hand side and the negative infinity counters for the minactivity are zero then add the variables as a clique for which all successive pairs of coefficients fullfill the following condition

minactivity + vals[i] + vals[i+1] > rhs

  and also add the binary to binary implication also for non-successive variables for which the same argument
  holds

minactivity + vals[i] + vals[j] > rhs

  e.g. 5.3 x1 + 3.6 x2 + 3.3 x3 + 2.1 x4 <= 5.5 (all x are binary) would lead to the clique (x1, x2, x3) and the
       binary to binary implications x1 = 1 => x4 = 0 and x2 = 1 => x4 = 0

b) if the constraint has a finite left hand side and the positive infinity counters for the maxactivity are zero then add the variables as a clique for which all successive pairs of coefficients fullfill the follwoing condition

maxactivity + vals[i] + vals[i-1] < lhs

  and also add the binary to binary implication also for non-successive variables for which the same argument
  holds

maxactivity + vals[i] + vals[j] < lhs

  e.g. you could multiply the above example by -1

c) the constraint has a finite right hand side and a finite minactivity then add the variables as a negated clique(clique on the negated variables) for which all successive pairs of coefficients fullfill the following condition

minactivity - vals[i] - vals[i-1] > rhs

  and also add the binary to binary implication also for non-successive variables for which the
  same argument holds

minactivity - vals[i] - vals[j] > rhs

  e.g. -4 x1 -3 x2 - 2 x3 + 2 x4 <= -4 would lead to the (negated) clique (~x1, ~x2) and the binary to binary
       implication x1 = 0 => x3 = 1

d) the constraint has a finite left hand side and a finite maxactivity then add the variables as a negated clique(clique on the negated variables) for which all successive pairs of coefficients fullfill the following condition

maxactivity - vals[i] - vals[i+1] < lhs

  and also add the binary to binary implication also for non-successive variables for which the same argument
  holds

maxactivity - vals[i] - vals[j] < lhs

  e.g. you could multiply the above example by -1

if the linear constraint represents a set-packing or set-partitioning constraint, the whole constraint is added as clique, (this part is done at the end of the method)

Parameters

scip	SCIP data structure
cons	linear constraint
maxeasyactivitydelta	maximum activity delta to run easy propagation on linear constraint
sortvars	should variables be used in sorted order?
nfixedvars	pointer to count number of fixed variables
nchgbds	pointer to count the total number of tightened bounds
cutoff	pointer to store TRUE, if a cutoff was found

Definition at line 7457 of file cons_linear.c.

static SCIP_RETCODE tightenSides	(	SCIP *	scip,
		SCIP_CONS *	cons,
		int *	nchgsides
	)

static

tightens left and right hand side of constraint due to integrality

Parameters

scip	SCIP data structure
cons	linear constraint
nchgsides	pointer to count number of side changes

Definition at line 8423 of file cons_linear.c.

References chgLhs(), chgRhs(), SCIP_CALL, SCIP_OKAY, SCIP_VARTYPE_CONTINUOUS, SCIPconsGetName(), SCIPdebugMessage, SCIPfeasCeil(), SCIPfeasFloor(), SCIPisInfinity(), SCIPisIntegral(), SCIPvarGetType(), and TRUE.

static SCIP_RETCODE consdataTightenCoefs	(	SCIP *	scip,
		SCIP_CONS *	cons,
		int *	nchgcoefs,
		int *	nchgsides
	)

static

tightens coefficients of binary, integer, and implicit integer variables due to activity bounds in presolving: given an inequality lhs <= a*x + ai*xi <= rhs, with a non-continuous variable li <= xi <= ui let minact := min{a*x + ai*xi}, maxact := max{a*x + ai*xi} (i) ai >= 0: if minact + ai >= lhs and maxact - ai <= rhs: (**)

a deviation from the lower/upper bound of xi would make the left/right hand side redundant
ai, lhs and rhs can be changed to have the same redundancy effect and the same results for xi fixed to its bounds, but with a reduced ai and tightened sides to tighten the LP relaxation
change coefficients: ai' := max(lhs - minact, maxact - rhs) lhs' := lhs - (ai - ai')*li rhs' := rhs - (ai - ai')*ui (ii) ai < 0: if minact - ai >= lhs and maxact + ai <= rhs: (***)
a deviation from the upper/lower bound of xi would make the left/right hand side redundant
ai, lhs and rhs can be changed to have the same redundancy effect and the same results for xi fixed to its bounds, but with a reduced ai and tightened sides to tighten the LP relaxation
change coefficients: ai' := min(rhs - maxact, minact - lhs) lhs' := lhs - (ai - ai')*ui rhs' := rhs - (ai - ai')*li

We further try to remove redundant variable from the constraint; Variables which fulfill conditions (**) or (***) are called surely non-redundant variables. A deviation of only one from their bound makes the lhs/rhs feasible (i.e., redundant), even if all other variables are set to their "worst" bound. If all variables which are not surely non-redundant cannot make the lhs/rhs redundant, even if they are set to their "best" bound, they can be removed from the constraint. E.g., for binary variables and an inequality x_1 +x_2 +10y_1 +10y_2 >= 5, setting either of the y_i to one suffices to fulfill the inequality, whereas the x_i do not contribute to feasibility and can be removed.

Parameters

scip	SCIP data structure
cons	linear constraint
nchgcoefs	pointer to count total number of changed coefficients
nchgsides	pointer to count number of side changes

Definition at line 8508 of file cons_linear.c.

static SCIP_RETCODE convertUnaryEquality	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_Bool *	cutoff,
		int *	nfixedvars,
		int *	ndelconss
	)

static

Parameters

scip	SCIP data structure
cons	linear constraint
cutoff	pointer to store TRUE, if a cutoff was found
nfixedvars	pointer to count number of fixed variables
ndelconss	pointer to count number of deleted constraints

Definition at line 8934 of file cons_linear.c.

static SCIP_RETCODE convertBinaryEquality	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_Bool *	cutoff,
		int *	naggrvars,
		int *	ndelconss
	)

static

Parameters

scip	SCIP data structure
cons	linear constraint
cutoff	pointer to store TRUE, if a cutoff was found
naggrvars	pointer to count number of aggregated variables
ndelconss	pointer to count number of deleted constraints

Definition at line 8990 of file cons_linear.c.

static void getNewSidesAfterAggregation	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata,
		SCIP_VAR *	slackvar,
		SCIP_Real	slackcoef,
		SCIP_Real *	newlhs,
		SCIP_Real *	newrhs
	)

static

calculates the new lhs and rhs of the constraint after the given variable is aggregated out

Parameters

scip	SCIP data structure
consdata	linear constraint data
slackvar	variable to be aggregated out
slackcoef	coefficient of variable in constraint
newlhs	pointer to store new lhs of constraint
newrhs	pointer to store new rhs of constraint

Definition at line 9048 of file cons_linear.c.

static SCIP_RETCODE convertLongEquality	(	SCIP *	scip,
		SCIP_CONSHDLRDATA *	conshdlrdata,
		SCIP_CONS *	cons,
		SCIP_Bool *	cutoff,
		int *	naggrvars,
		int *	ndelconss
	)

static

Parameters

scip	SCIP data structure
conshdlrdata	linear constraint handler data
cons	linear constraint
cutoff	pointer to store TRUE, if a cutoff was found
naggrvars	pointer to count number of aggregated variables
ndelconss	pointer to count number of deleted constraints

Definition at line 9104 of file cons_linear.c.

static SCIP_Bool checkEqualObjective	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata,
		SCIP_Real *	scale,
		SCIP_Real *	offset
	)

static

checks if the given variables and their coefficient are equal (w.r.t. scaling factor) to the objective function

Parameters

scip	SCIP data structure
consdata	linear constraint data
scale	pointer to store the scaling factor between the constraint and the objective function
offset	pointer to store the offset of the objective function resulting by this constraint

Definition at line 9643 of file cons_linear.c.

static SCIP_RETCODE checkPartialObjective	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_CONSHDLRDATA *	conshdlrdata
	)

static

check if the linear equality constraint is equal to a subset of the objective function; if so we can remove the objective coefficients and add an objective offset

Parameters

scip	SCIP data structure
cons	linear equation constraint
conshdlrdata	linear constraint handler data

Definition at line 9720 of file cons_linear.c.

static SCIP_RETCODE updateCutoffbound	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_Real	primalbound
	)

static

updates the cutoff if the given primal bound (which is implied by the given constraint) is better

Parameters

scip	SCIP data structure
cons	constraint
primalbound	feasible primal bound

Definition at line 9787 of file cons_linear.c.

static SCIP_RETCODE checkParallelObjective	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_CONSHDLRDATA *	conshdlrdata
	)

static

check if the linear constraint is parallel to objective function; if so update the cutoff bound and avoid that the constraint enters the LP by setting the initial and separated flag to FALSE

Parameters

scip	SCIP data structure
cons	linear constraint
conshdlrdata	linear constraint handler data

Definition at line 9833 of file cons_linear.c.

static SCIP_RETCODE convertEquality	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_CONSHDLRDATA *	conshdlrdata,
		SCIP_Bool *	cutoff,
		int *	nfixedvars,
		int *	naggrvars,
		int *	ndelconss
	)

static

converts special equalities

Parameters

scip	SCIP data structure
cons	linear constraint
conshdlrdata	linear constraint handler data
cutoff	pointer to store TRUE, if a cutoff was found
nfixedvars	pointer to count number of fixed variables
naggrvars	pointer to count number of aggregated variables
ndelconss	pointer to count number of deleted constraints

Definition at line 9958 of file cons_linear.c.

static SCIP_Bool consdataIsResidualIntegral	(	SCIP *	scip,
		SCIP_CONSDATA *	consdata,
		int	pos,
		SCIP_Real	val
	)

static

returns whether the linear sum of all variables/coefficients except the given one divided by the given value is always integral

Parameters

scip	SCIP data structure
consdata	linear constraint
pos	position of variable to be left out
val	value to divide the coefficients by

Definition at line 10013 of file cons_linear.c.

References NULL.

static void calculateMinvalAndMaxval	(	SCIP *	scip,
		SCIP_Real	side,
		SCIP_Real	val,
		SCIP_Real	minresactivity,
		SCIP_Real	maxresactivity,
		SCIP_Real *	minval,
		SCIP_Real *	maxval
	)

static

Parameters

scip	SCIP data structure
side	lhs or rhs
val	coefficient
minresactivity	minimal residual activity
maxresactivity	maximal residual activity
minval	pointer to store calculated minval
maxval	pointer to store calculated maxval

Definition at line 10039 of file cons_linear.c.

References dualPresolve(), SCIP_Bool, and SCIPisInfinity().

static SCIP_RETCODE dualPresolve	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_Bool *	cutoff,
		int *	nfixedvars,
		int *	naggrvars,
		int *	ndelconss
	)

static

Parameters

scip	SCIP data structure
cons	linear constraint
cutoff	pointer to store TRUE, if a cutoff was found
nfixedvars	pointer to count number of fixed variables
naggrvars	pointer to count number of aggregated variables
ndelconss	pointer to count number of deleted constraints

Definition at line 10084 of file cons_linear.c.

Referenced by calculateMinvalAndMaxval().

static int getVarWeight ( SCIP_VAR * var )

static

gets weight for variable in a "weighted number of variables" sum

Parameters

var	variable to get weight for

Definition at line 10507 of file cons_linear.c.

References NULL, SCIP_Bool, and SCIPconsGetData().

Referenced by aggregateConstraints().

static SCIP_RETCODE aggregateVariables	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_Bool *	cutoff,
		int *	nfixedvars,
		int *	naggrvars,
		int *	ndelconss
	)

static

tries to aggregate variables in equations a^Tx = lhs in case there are at most two binary variables with an odd coefficient and all other variables are not continuous and have an even coefficient then:

exactly one odd binary variables this binary variables y can be fixed to 0 if the lhs is even and to 1 if the lhs is odd
- lhs is odd -> y = 1
- lhs is even -> y = 0
exactly two odd binary variables aggregate the two binary variables with odd coefficient
- lhs is odd -> exactly one of the variable has to be 1 -> var1 + var2 = 1
- lhs is even -> both have to take the same value -> var1 - var2 = 0

Parameters

scip	SCIP data structure
cons	linear constraint
cutoff	pointer to store TRUE, if a cutoff was found
nfixedvars	pointer to count number of fixed variables
naggrvars	pointer to count number of aggregated variables
ndelconss	pointer to count number of deleted constraints

Definition at line 10540 of file cons_linear.c.

Referenced by checkCons(), and SCIP_DECL_CONSPRESOL().

static SCIP_DECL_SORTINDCOMP ( consdataCompSim )

static

sorting method for constraint data, compares two variables on given indices, continuous variables will be sorted to the end and for all other variables the sortation will be in non-increasing order of their absolute value of the coefficients

Definition at line 10706 of file cons_linear.c.

static SCIP_RETCODE rangedRowSimplify	(	SCIP *	scip,
		SCIP_CONS *	cons,
		int *	nchgcoefs,
		int *	nchgsides
	)

static

tries to simplify coefficients and delete variables in ranged row of the form lhs <= a^Tx <= rhs, e.g. using the greatest common divisor

lhs <= a^Tx <= rhs, forall a_i >= lhs, a_i <= rhs, and forall pairs a_i + a_j > rhs then we can change this constraint to 1^Tx = 1

Parameters

scip	SCIP data structure
cons	linear constraint
nchgcoefs	pointer to store the amount of changed coefficients
nchgsides	pointer to store the amount of changed sides

Definition at line 10746 of file cons_linear.c.

static SCIP_RETCODE simplifyInequalities	(	SCIP *	scip,
		SCIP_CONS *	cons,
		int *	nchgcoefs,
		int *	nchgsides
	)

static

tries to simplify coefficients and delete variables in constraints of the form lhs <= a^Tx <= rhs for equations

See also: rangedRowSimplify() will be called

there are several different coefficient reduction steps which will be applied

We try to determine parts of the constraint which will not change anything on (in-)feasibility of the constraint

e.g. 5x1 + 5x2 + 3z1 <= 8 => 3z1 is redundant if all x are binary and -2 < 3z1 <= 3
We try to remove redundant fractional parts in a constraint

e.g. 5.2x1 + 5.1x2 + 3x3 <= 8.3 => will be changed to 5x1 + 5x2 + 3x3 <= 8 if all x are binary
We are using the greatest common divisor for further reductions

e.g. 10x1 + 5y2 + 5x3 + 3x4 <= 15 => will be changed to 2x1 + y2 + x3 + x4 <= 3 if all xi are binary and y2 is integral

Parameters

scip	SCIP data structure
cons	linear constraint
nchgcoefs	pointer to store the amount of changed coefficients
nchgsides	pointer to store the amount of changed sides

Definition at line 10858 of file cons_linear.c.

static SCIP_RETCODE aggregateConstraints	(	SCIP *	scip,
		SCIP_CONS *	cons0,
		SCIP_CONS *	cons1,
		int *	commonidx0,
		int *	commonidx1,
		int *	diffidx0minus1,
		int *	diffidx1minus0,
		int	nvarscommon,
		int	commonidxweight,
		int	diffidx0minus1weight,
		int	diffidx1minus0weight,
		SCIP_Real	maxaggrnormscale,
		int *	nchgcoefs,
		SCIP_Bool *	aggregated
	)

static

Parameters

scip	SCIP data structure
cons0	(in)equality to modify
cons1	equality to use for aggregation of cons0
commonidx0	array with indices of variables in cons0, that appear also in cons1
commonidx1	array with indices of variables in cons1, that appear also in cons0
diffidx0minus1	array with indices of variables in cons0, that don't appear in cons1
diffidx1minus0	array with indices of variables in cons1, that don't appear in cons0
nvarscommon	number of variables, that appear in both constraints
commonidxweight	variable weight sum of common variables
diffidx0minus1weight	variable weight sum of variables in cons0, that don't appear in cons1
diffidx1minus0weight	variable weight sum of variables in cons1, that don't appear in cons0
maxaggrnormscale	maximal allowed relative gain in maximum norm for constraint aggregation
nchgcoefs	pointer to count the number of changed coefficients
aggregated	pointer to store whether an aggregation was made

Definition at line 12055 of file cons_linear.c.

References consdataGetMaxAbsval(), FALSE, getVarWeight(), normalizeCons(), NULL, REALABS, SCIP_Bool, SCIP_CALL, SCIP_DECL_HASHGETKEY(), SCIP_DECL_HASHKEYEQ(), SCIP_OKAY, SCIP_Real, SCIPaddCons(), SCIPallocBufferArray, SCIPconsGetData(), SCIPconsGetName(), SCIPconsGetNUpgradeLocks(), SCIPconsIsActive(), SCIPconsIsChecked(), SCIPconsIsDynamic(), SCIPconsIsEnforced(), SCIPconsIsInitial(), SCIPconsIsLocal(), SCIPconsIsModifiable(), SCIPconsIsPropagated(), SCIPconsIsRemovable(), SCIPconsIsSeparated(), SCIPconsIsStickingAtNode(), SCIPcreateConsLinear(), SCIPdebugMessage, SCIPdebugPrintCons, SCIPdelCons(), SCIPfreeBufferArray, SCIPinfinity(), SCIPisEQ(), SCIPisInfinity(), SCIPisIntegral(), SCIPisLE(), SCIPisPositive(), SCIPisZero(), SCIPreleaseCons(), and TRUE.

static SCIP_DECL_HASHGETKEY ( hashGetKeyLinearcons )

static

gets the key of the given element

Definition at line 12368 of file cons_linear.c.

Referenced by aggregateConstraints().

static SCIP_DECL_HASHKEYEQ ( hashKeyEqLinearcons )

static

returns TRUE iff both keys are equal; two constraints are equal if they have the same variables and the coefficients are either equal or negated

Definition at line 12378 of file cons_linear.c.

Referenced by aggregateConstraints().

static SCIP_DECL_HASHKEYVAL ( hashKeyValLinearcons )

static

returns the hash value of the key

Definition at line 12433 of file cons_linear.c.

static SCIP_RETCODE detectRedundantConstraints	(	SCIP *	scip,
		BMS_BLKMEM *	blkmem,
		SCIP_CONS **	conss,
		int	nconss,
		int *	firstchange,
		SCIP_Bool *	cutoff,
		int *	ndelconss,
		int *	nchgsides
	)

static

compares each constraint with all other constraints for possible redundancy and removes or changes constraint accordingly; in contrast to preprocessConstraintPairs(), it uses a hash table

Parameters

scip	SCIP data structure
blkmem	block memory
conss	constraint set
nconss	number of constraints in constraint set
firstchange	pointer to store first changed constraint
cutoff	pointer to store TRUE, if a cutoff was found
ndelconss	pointer to count number of deleted constraints
nchgsides	pointer to count number of changed left/right hand sides

Definition at line 12484 of file cons_linear.c.

static SCIP_RETCODE preprocessConstraintPairs	(	SCIP *	scip,
		SCIP_CONS **	conss,
		int	firstchange,
		int	chkind,
		SCIP_Real	maxaggrnormscale,
		SCIP_Bool *	cutoff,
		int *	ndelconss,
		int *	nchgsides,
		int *	nchgcoefs
	)

static

compares constraint with all prior constraints for possible redundancy or aggregation, and removes or changes constraint accordingly

Parameters

scip	SCIP data structure
conss	constraint set
firstchange	first constraint that changed since last pair preprocessing round
chkind	index of constraint to check against all prior indices upto startind
maxaggrnormscale	maximal allowed relative gain in maximum norm for constraint aggregation
cutoff	pointer to store TRUE, if a cutoff was found
ndelconss	pointer to count number of deleted constraints
nchgsides	pointer to count number of changed left/right hand sides
nchgcoefs	pointer to count number of changed coefficients

Definition at line 12665 of file cons_linear.c.

static SCIP_RETCODE fullDualPresolve	(	SCIP *	scip,
		SCIP_CONS **	conss,
		int	nconss,
		SCIP_Bool *	cutoff,
		int *	nchgbds
	)

static

applies full dual presolving on variables that only appear in linear constraints

Parameters

scip	SCIP data structure
conss	constraint set
nconss	number of constraints
cutoff	pointer to store TRUE, if a cutoff was found
nchgbds	pointer to count the number of bound changes

Definition at line 13263 of file cons_linear.c.

static SCIP_DECL_CONSHDLRCOPY ( conshdlrCopyLinear )

static

copy method for constraint handler plugins (called when SCIP copies plugins)

Definition at line 13732 of file cons_linear.c.

References CONSHDLR_NAME, conshdlrdataFree(), NULL, SCIPconshdlrGetData(), SCIPconshdlrGetName(), and SCIPconshdlrSetData().

static SCIP_DECL_CONSFREE ( consFreeLinear )

static

destructor of constraint handler to free constraint handler data (called when SCIP is exiting)

Definition at line 13748 of file cons_linear.c.

References NULL, and SCIPconshdlrGetData().

static SCIP_DECL_CONSINIT ( consInitLinear )

static

initialization method of constraint handler (called after problem was transformed)

Definition at line 13770 of file cons_linear.c.

static SCIP_DECL_CONSEXIT ( consExitLinear )

static

deinitialization method of constraint handler (called before transformed problem is freed)

Definition at line 13796 of file cons_linear.c.

static SCIP_DECL_CONSEXITPRE ( consExitpreLinear )

static

presolving deinitialization method of constraint handler (called after presolving has been finished)

Definition at line 14174 of file cons_linear.c.

static SCIP_DECL_CONSEXITSOL ( consExitsolLinear )

static

solving process deinitialization method of constraint handler (called before branch and bound process data is freed)

Definition at line 14252 of file cons_linear.c.

static SCIP_DECL_CONSDELETE ( consDeleteLinear )

static

frees specific constraint data

Definition at line 14299 of file cons_linear.c.

static SCIP_DECL_CONSTRANS ( consTransLinear )

static

transforms constraint data into data belonging to the transformed problem

Definition at line 14329 of file cons_linear.c.

static SCIP_DECL_CONSINITLP ( consInitlpLinear )

static

LP initialization method of constraint handler (called before the initial LP relaxation at a node is solved)

Definition at line 14376 of file cons_linear.c.

References NULL, SCIP_Bool, and SCIP_Real.

static SCIP_DECL_CONSSEPALP ( consSepalpLinear )

static

separation method of constraint handler for LP solutions

Definition at line 14397 of file cons_linear.c.

static SCIP_DECL_CONSSEPASOL ( consSepasolLinear )

static

separation method of constraint handler for arbitrary primal solutions

Definition at line 14468 of file cons_linear.c.

static SCIP_DECL_CONSENFOLP ( consEnfolpLinear )

static

constraint enforcing method of constraint handler for LP solutions

Definition at line 14526 of file cons_linear.c.

References addRelaxation(), checkCons(), CONSHDLR_NAME, FALSE, NULL, SCIP_Bool, SCIP_CALL, SCIP_CUTOFF, SCIP_DECL_CONSENFOPS(), SCIP_FEASIBLE, SCIP_OKAY, SCIP_SEPARATED, SCIPconshdlrGetData(), and SCIPconshdlrGetName().

static SCIP_DECL_CONSENFOPS ( consEnfopsLinear )

static

constraint enforcing method of constraint handler for pseudo solutions

Definition at line 14589 of file cons_linear.c.

Referenced by SCIP_DECL_CONSENFOLP().

static SCIP_DECL_CONSCHECK ( consCheckLinear )

static

feasibility check method of constraint handler for integral solutions

Definition at line 14637 of file cons_linear.c.

References checkCons(), consdataGetActivity(), CONSHDLR_NAME, FALSE, NULL, SCIP_Bool, SCIP_CALL, SCIP_DECL_CONSPROP(), SCIP_FEASIBLE, SCIP_INFEASIBLE, SCIP_INVALID, SCIP_OKAY, SCIP_Real, SCIPconsGetData(), SCIPconshdlrGetData(), SCIPconshdlrGetName(), SCIPinfoMessage(), SCIPisFeasGT(), SCIPisFeasLT(), and SCIPprintCons().

static SCIP_DECL_CONSPROP ( consPropLinear )

static

domain propagation method of constraint handler

Definition at line 14697 of file cons_linear.c.

Referenced by SCIP_DECL_CONSCHECK().

static SCIP_DECL_CONSPRESOL ( consPresolLinear )

static

presolving method of constraint handler

Definition at line 14768 of file cons_linear.c.

static SCIP_DECL_CONSRESPROP ( consRespropLinear )

static

propagation conflict resolving method of constraint handler

Definition at line 15212 of file cons_linear.c.

References NULL, SCIP_Bool, SCIPconsGetData(), and SCIPisInfinity().

static SCIP_DECL_CONSLOCK ( consLockLinear )

static

variable rounding lock method of constraint handler

Definition at line 15227 of file cons_linear.c.

References NULL, performVarDeletions(), SCIP_CALL, SCIP_DECL_CONSDELVARS(), SCIP_OKAY, SCIPaddVarLocks(), and SCIPisPositive().

static SCIP_DECL_CONSDELVARS ( consDelvarsLinear )

static

variable deletion method of constraint handler

Definition at line 15275 of file cons_linear.c.

References consdataPrint(), NULL, SCIP_CALL, SCIP_DECL_CONSCOPY(), SCIP_OKAY, and SCIPconsGetData().

Referenced by SCIP_DECL_CONSLOCK().

static SCIP_DECL_CONSPRINT ( consPrintLinear )

static

constraint display method of constraint handler

Definition at line 15291 of file cons_linear.c.

static SCIP_DECL_CONSCOPY ( consCopyLinear )

static

constraint copying method of constraint handler

Definition at line 15304 of file cons_linear.c.

Referenced by SCIP_DECL_CONSDELVARS().

static SCIP_DECL_CONSPARSE ( consParseLinear )

static

constraint parsing method of constraint handler

Definition at line 15335 of file cons_linear.c.

static SCIP_DECL_CONSGETVARS ( consGetVarsLinear )

static

constraint method of constraint handler which returns the variables (if possible)

Definition at line 15493 of file cons_linear.c.

References NULL, SCIP_OKAY, SCIPconsGetData(), and TRUE.

static SCIP_DECL_CONSGETNVARS ( consGetNVarsLinear )

static

constraint method of constraint handler which returns the number of variables (if possible)

Definition at line 15515 of file cons_linear.c.

References EVENTHDLR_NAME, NULL, SCIPconsGetData(), and SCIPeventhdlrGetName().

static SCIP_DECL_EVENTEXEC ( eventExecLinear )

static

Definition at line 15533 of file cons_linear.c.

static SCIP_DECL_CONFLICTEXEC ( conflictExecLinear )

static

Definition at line 15701 of file cons_linear.c.

static SCIP_DECL_QUADCONSUPGD ( upgradeConsQuadratic )

static

upgrades quadratic constraints with only and at least one linear variables into a linear constraint

Definition at line 15790 of file cons_linear.c.

References NULL, SCIP_CALL, SCIP_DECL_NONLINCONSUPGD(), SCIP_OKAY, SCIPconsGetName(), SCIPconsIsChecked(), SCIPconsIsDynamic(), SCIPconsIsEnforced(), SCIPconsIsInitial(), SCIPconsIsLocal(), SCIPconsIsModifiable(), SCIPconsIsPropagated(), SCIPconsIsRemovable(), SCIPconsIsSeparated(), SCIPconsIsStickingAtNode(), SCIPcreateConsLinear(), SCIPdebugMessage, SCIPdebugPrintCons, SCIPgetCoefsLinearVarsQuadratic(), SCIPgetExprgraphNodeNonlinear(), SCIPgetLhsQuadratic(), SCIPgetLinearVarsQuadratic(), SCIPgetNLinearVarsNonlinear(), SCIPgetNLinearVarsQuadratic(), and SCIPgetRhsQuadratic().

static SCIP_DECL_NONLINCONSUPGD ( upgradeConsNonlinear )

static

tries to upgrade a nonlinear constraint into a linear constraint

Definition at line 15832 of file cons_linear.c.

References EVENTHDLR_DESC, EVENTHDLR_NAME, NULL, SCIP_CALL, SCIP_OKAY, SCIPconsGetName(), SCIPconsIsChecked(), SCIPconsIsDynamic(), SCIPconsIsEnforced(), SCIPconsIsInitial(), SCIPconsIsLocal(), SCIPconsIsModifiable(), SCIPconsIsPropagated(), SCIPconsIsRemovable(), SCIPconsIsSeparated(), SCIPconsIsStickingAtNode(), SCIPcreateConsLinear(), SCIPgetLhsNonlinear(), SCIPgetLinearCoefsNonlinear(), SCIPgetLinearVarsNonlinear(), SCIPgetNLinearVarsNonlinear(), SCIPgetRhsNonlinear(), SCIPincludeConshdlrLinear(), and SCIPincludeEventhdlrBasic().

Referenced by SCIP_DECL_QUADCONSUPGD().

SCIP_RETCODE SCIPincludeConshdlrLinear ( SCIP * scip )

creates the handler for linear constraints and includes it in SCIP

Parameters

scip	SCIP data structure

Definition at line 15871 of file cons_linear.c.

Referenced by SCIP_DECL_NONLINCONSUPGD(), and SCIPincludeDefaultPlugins().

SCIP_RETCODE SCIPincludeLinconsUpgrade	(	SCIP *	scip,
		SCIP_DECL_LINCONSUPGD((*linconsupgd))	,
		int	priority,
		const char *	conshdlrname
	)

includes a linear constraint update method into the linear constraint handler

Parameters

scip	SCIP data structure
priority	priority of upgrading method
conshdlrname	name of the constraint handler

Definition at line 16047 of file cons_linear.c.

Referenced by SCIPincludeConshdlrIndicator(), SCIPincludeConshdlrLogicor(), SCIPincludeConshdlrVarbound(), and SCIPincludeConshdlrXor().

SCIP_RETCODE SCIPcreateConsLinear	(	SCIP *	scip,
		SCIP_CONS **	cons,
		const char *	name,
		int	nvars,
		SCIP_VAR **	vars,
		SCIP_Real *	vals,
		SCIP_Real	lhs,
		SCIP_Real	rhs,
		SCIP_Bool	initial,
		SCIP_Bool	separate,
		SCIP_Bool	enforce,
		SCIP_Bool	check,
		SCIP_Bool	propagate,
		SCIP_Bool	local,
		SCIP_Bool	modifiable,
		SCIP_Bool	dynamic,
		SCIP_Bool	removable,
		SCIP_Bool	stickingatnode
	)

creates and captures a linear constraint

Note: the constraint gets captured, hence at one point you have to release it using the method SCIPreleaseCons()

Parameters

scip	SCIP data structure
cons	pointer to hold the created constraint
name	name of constraint
nvars	number of nonzeros in the constraint
vars	array with variables of constraint entries
vals	array with coefficients of constraint entries
lhs	left hand side of constraint
rhs	right hand side of constraint
initial	should the LP relaxation of constraint be in the initial LP? Usually set to TRUE. Set to FALSE for 'lazy constraints'.
separate	should the constraint be separated during LP processing? Usually set to TRUE.
enforce	should the constraint be enforced during node processing? TRUE for model constraints, FALSE for additional, redundant constraints.
check	should the constraint be checked for feasibility? TRUE for model constraints, FALSE for additional, redundant constraints.
propagate	should the constraint be propagated during node processing? Usually set to TRUE.
local	is constraint only valid locally? Usually set to FALSE. Has to be set to TRUE, e.g., for branching constraints.
modifiable	is constraint modifiable (subject to column generation)? Usually set to FALSE. In column generation applications, set to TRUE if pricing adds coefficients to this constraint.
dynamic	Is constraint subject to aging? Usually set to FALSE. Set to TRUE for own cuts which are separated as constraints.
removable	should the relaxation be removed from the LP due to aging or cleanup? Usually set to FALSE. Set to TRUE for 'lazy constraints' and 'user cuts'.
stickingatnode	should the constraint always be kept at the node where it was added, even if it may be moved to a more global node? Usually set to FALSE. Set to TRUE to for constraints that represent node data.

Definition at line 16099 of file cons_linear.c.

References consCatchAllEvents(), consdataCreate(), CONSHDLR_NAME, FALSE, needEvents(), NULL, REALABS, SCIP_CALL, SCIP_INVALIDDATA, SCIP_OKAY, SCIP_PLUGINNOTFOUND, SCIP_Real, SCIP_STAGE_EXITPRESOLVE, SCIPABORT, SCIPconshdlrGetData(), SCIPcreateCons(), SCIPcreateConsBasicLinear(), SCIPcreateConsLinear(), SCIPduplicateBufferArray, SCIPerrorMessage, SCIPfindConshdlr(), SCIPfreeBufferArray, SCIPgetProbvarLinearSum(), SCIPgetStage(), SCIPinfinity(), SCIPisInfinity(), SCIPisTransformed(), SCIPreallocBufferArray, and TRUE.

Referenced by addBranchingComplementaritiesSOS1(), addExtendedAsymmetricFormulation(), addExtendedFlowFormulation(), addLocalBranchingConstraint(), aggregateConstraints(), applyFixings(), consdataLinearize(), copyCuts(), CREATE_CONSTRAINT(), createAndAddLinearCons(), createConstraints(), createCoveringProblem(), createLinearCons(), createNAryBranch(), createRows(), createSubproblem(), createSubSCIP(), createSubscip(), dualPresolve(), fixDeleteOrUpgradeCons(), fixVariableZeroNode(), forbidCover(), getFixedVariable(), preprocessConstraintPairs(), presolveCreateBenTalNemirovskiApproxDim3(), presolveCreateGlineurApproxDim3(), presolveFindDuplicates(), presolveFindDuplicatesUpgradeCons(), presolveRemoveFixedVariables(), presolveTryAddLinearReform(), propIndicator(), readCnf(), readConstraints(), readOPBFile(), readRows(), replaceByLinearConstraints(), replaceViolatedByLinearConstraints(), SCIP_DECL_CONSCOPY(), SCIP_DECL_CONSINITPRE(), SCIP_DECL_CONSPRESOL(), SCIP_DECL_NONLINCONSUPGD(), SCIP_DECL_QUADCONSUPGD(), SCIPapplyZeroobj(), SCIPcopyConsLinear(), SCIPcreateConsIndicator(), SCIPcreateConsLinear(), SCIPgetVarCopy(), selectVarMultAggrBranching(), tightenBounds(), tryUpgradingLogicor(), tryUpgradingSetppc(), and upgradeLinearSuperindicator().

SCIP_RETCODE SCIPcreateConsBasicLinear	(	SCIP *	scip,
		SCIP_CONS **	cons,
		const char *	name,
		int	nvars,
		SCIP_VAR **	vars,
		SCIP_Real *	vals,
		SCIP_Real	lhs,
		SCIP_Real	rhs
	)

creates and captures a linear constraint in its most basic version, i. e., all constraint flags are set to their basic value as explained for the method SCIPcreateConsLinear(); all flags can be set via SCIPsetConsFLAGNAME-methods in scip.h

See also: SCIPcreateConsLinear() for information about the basic constraint flag configuration

Note: the constraint gets captured, hence at one point you have to release it using the method SCIPreleaseCons()

Parameters

scip	SCIP data structure
cons	pointer to hold the created constraint
name	name of constraint
nvars	number of nonzeros in the constraint
vars	array with variables of constraint entries
vals	array with coefficients of constraint entries
lhs	left hand side of constraint
rhs	right hand side of constraint

Definition at line 16291 of file cons_linear.c.

Referenced by createMIP(), SCIPapplyProximity(), SCIPcreateConsLinear(), and SCIPcreateFiniteSolCopy().

SCIP_RETCODE SCIPcopyConsLinear	(	SCIP *	scip,
		SCIP_CONS **	cons,
		SCIP *	sourcescip,
		const char *	name,
		int	nvars,
		SCIP_VAR **	sourcevars,
		SCIP_Real *	sourcecoefs,
		SCIP_Real	lhs,
		SCIP_Real	rhs,
		SCIP_HASHMAP *	varmap,
		SCIP_HASHMAP *	consmap,
		SCIP_Bool	initial,
		SCIP_Bool	separate,
		SCIP_Bool	enforce,
		SCIP_Bool	check,
		SCIP_Bool	propagate,
		SCIP_Bool	local,
		SCIP_Bool	modifiable,
		SCIP_Bool	dynamic,
		SCIP_Bool	removable,
		SCIP_Bool	stickingatnode,
		SCIP_Bool	global,
		SCIP_Bool *	valid
	)

creates by copying and captures a linear constraint

Parameters

scip	target SCIP data structure
cons	pointer to store the created target constraint
sourcescip	source SCIP data structure
name	name of constraint
nvars	number of variables in source variable array
sourcevars	source variables of the linear constraints
sourcecoefs	coefficient array of the linear constraint, or NULL if all coefficients are one
lhs	left hand side of the linear constraint
rhs	right hand side of the linear constraint
varmap	a SCIP_HASHMAP mapping variables of the source SCIP to corresponding variables of the target SCIP
consmap	a hashmap to store the mapping of source constraints to the corresponding target constraints
initial	should the LP relaxation of constraint be in the initial LP?
separate	should the constraint be separated during LP processing?
enforce	should the constraint be enforced during node processing?
check	should the constraint be checked for feasibility?
propagate	should the constraint be propagated during node processing?
local	is constraint only valid locally?
modifiable	is constraint modifiable (subject to column generation)?
dynamic	is constraint subject to aging?
removable	should the relaxation be removed from the LP due to aging or cleanup?
stickingatnode	should the constraint always be kept at the node where it was added, even if it may be moved to a more global node?
global	create a global or a local copy?
valid	pointer to store if the copying was valid

Definition at line 16311 of file cons_linear.c.

References CONSHDLR_NAME, FALSE, NULL, SCIP_CALL, SCIP_INVALIDDATA, SCIP_OKAY, SCIP_Real, SCIPaddCoefLinear(), SCIPallocBufferArray, SCIPconsGetHdlr(), SCIPconshdlrGetName(), SCIPcreateConsLinear(), SCIPduplicateBufferArray, SCIPerrorMessage, SCIPfreeBufferArray, SCIPgetProbvarLinearSum(), SCIPgetVarCopy(), SCIPisGT(), SCIPisInfinity(), SCIPreallocBufferArray, SCIPvarGetOrigvarSum(), SCIPvarIsOriginal(), and TRUE.

Referenced by SCIP_DECL_CONSCOPY().

SCIP_RETCODE SCIPaddCoefLinear	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_VAR *	var,
		SCIP_Real	val
	)

adds coefficient to linear constraint (if it is not zero)

Parameters

scip	SCIP data structure
cons	constraint data
var	variable of constraint entry
val	coefficient of constraint entry

Definition at line 16436 of file cons_linear.c.

References addCoef(), chgLhs(), chgRhs(), NULL, REALABS, SCIP_Bool, SCIP_CALL, SCIP_INVALIDDATA, SCIP_OKAY, SCIP_Real, SCIPABORT, SCIPallocBufferArray, SCIPchgCoefLinear(), SCIPconsGetData(), SCIPconsGetName(), SCIPerrorMessage, SCIPfreeBufferArray, SCIPgetProbvarLinearSum(), SCIPinfinity(), SCIPisInfinity(), SCIPreallocBufferArray, SCIPvarGetName(), and TRUE.

Referenced by addCoefTerm(), applyFixings(), consdataLinearize(), createAndAddLinearCons(), createMIP(), createSubSCIP(), getBoundConsFromVertices(), readCols(), readIndicators(), readLinearCoefs(), SCIP_DECL_CONSINITPRE(), SCIP_DECL_CONSPRESOL(), SCIP_DECL_NONLINCONSUPGD(), SCIP_DECL_QUADCONSUPGD(), SCIPaddCoefPseudoboolean(), SCIPaddVarIndicator(), SCIPapplyProximity(), SCIPapplyZeroobj(), SCIPchgCoefLinear(), SCIPcopyConsLinear(), SCIPcreateConsIndicator(), SCIPcreateFiniteSolCopy(), SCIPgetVarCopy(), tryUpgradingLogicor(), and tryUpgradingSetppc().

SCIP_RETCODE SCIPchgCoefLinear	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_VAR *	var,
		SCIP_Real	val
	)

changes coefficient of variable in linear constraint; deletes the variable if coefficient is zero; adds variable if not yet contained in the constraint

Note: This method may only be called during problem creation stage for an original constraint and variable.; This method requires linear time to search for occurences of the variable in the constraint data.

Parameters

scip	SCIP data structure
cons	constraint data
var	variable of constraint entry
val	new coefficient of constraint entry

Definition at line 16597 of file cons_linear.c.

References chgCoefPos(), delCoefPos(), FALSE, NULL, SCIP_CALL, SCIP_INVALIDDATA, SCIP_OKAY, SCIP_STAGE_PROBLEM, SCIPaddCoefLinear(), SCIPchgCoefLinear(), SCIPconsGetData(), SCIPconsIsOriginal(), SCIPdelCoefLinear(), SCIPerrorMessage, SCIPgetStage(), SCIPisZero(), SCIPvarIsOriginal(), and TRUE.

Referenced by SCIPaddCoefLinear(), and SCIPchgCoefLinear().

SCIP_RETCODE SCIPdelCoefLinear	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_VAR *	var
	)

deletes variable from linear constraint

Note: This method may only be called during problem creation stage for an original constraint and variable.; This method requires linear time to search for occurences of the variable in the constraint data.

Parameters

scip	SCIP data structure
cons	constraint data
var	variable of constraint entry

Definition at line 16665 of file cons_linear.c.

References CONSHDLR_NAME, NULL, SCIP_INVALID, SCIPABORT, SCIPconsGetHdlr(), SCIPconshdlrGetName(), and SCIPerrorMessage.

Referenced by SCIPchgCoefLinear().

SCIP_Real SCIPgetLhsLinear	(	SCIP *	scip,
		SCIP_CONS *	cons
	)

gets left hand side of linear constraint

Parameters

scip	SCIP data structure
cons	constraint data

Definition at line 16681 of file cons_linear.c.

Referenced by addAltLPConstraint(), addLinearConstraints(), checkConsnames(), checkLinearConssVarboundSOS1(), getLinearConsSides(), printRangeSection(), readIndicators(), readNonlinearExprs(), readQCMatrix(), readQuadraticCoefs(), readRanges(), readRhs(), SCIP_DECL_CONSLOCK(), SCIP_DECL_CONSPARSE(), SCIP_DECL_PARAMCHGD(), SCIP_DECL_PRESOLEXEC(), SCIP_DECL_READERWRITE(), SCIPmakeIndicatorFeasible(), SCIPmatrixCreate(), SCIPwriteGms(), SCIPwriteLp(), SCIPwritePip(), tightenVarsBoundsSOS1(), upgradeIndicatorSuperindicator(), upgradeLinearSuperindicator(), writeFzn(), and writeOpbConstraints().

SCIP_Real SCIPgetRhsLinear	(	SCIP *	scip,
		SCIP_CONS *	cons
	)

gets right hand side of linear constraint

Parameters

scip	SCIP data structure
cons	constraint data

Definition at line 16705 of file cons_linear.c.

Referenced by addAltLPConstraint(), addLinearConstraints(), checkLinearConssVarboundSOS1(), getLinearConsSides(), printRangeSection(), propIndicator(), readIndicators(), readNonlinearExprs(), readQCMatrix(), readQuadraticCoefs(), readRanges(), readRhs(), SCIP_DECL_CONSLOCK(), SCIP_DECL_CONSPARSE(), SCIP_DECL_PARAMCHGD(), SCIP_DECL_PRESOLEXEC(), SCIP_DECL_READERWRITE(), SCIPapplyProximity(), SCIPmakeIndicatorFeasible(), SCIPmatrixCreate(), SCIPwriteGms(), SCIPwriteLp(), SCIPwritePip(), tightenVarsBoundsSOS1(), upgradeIndicatorSuperindicator(), upgradeLinearSuperindicator(), writeFzn(), writeOpbConstraints(), and writeOpbObjective().

SCIP_RETCODE SCIPchgLhsLinear	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_Real	lhs
	)

changes left hand side of linear constraint

Parameters

scip	SCIP data structure
cons	constraint data
lhs	new left hand side

Definition at line 16729 of file cons_linear.c.

References chgRhs(), CONSHDLR_NAME, SCIP_CALL, SCIP_INVALIDDATA, SCIP_OKAY, SCIPconsGetHdlr(), SCIPconshdlrGetName(), and SCIPerrorMessage.

Referenced by applyFixings(), chgLhsLinearCons(), fixDiscreteVars(), readIndicators(), readRanges(), readRhs(), SCIP_DECL_PRESOLEXEC(), and tryUpgradingLogicor().

SCIP_RETCODE SCIPchgRhsLinear	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_Real	rhs
	)

changes right hand side of linear constraint

Parameters

scip	SCIP data structure
cons	constraint data
rhs	new right hand side

Definition at line 16750 of file cons_linear.c.

References CONSHDLR_NAME, NULL, SCIPABORT, SCIPconsGetHdlr(), SCIPconshdlrGetName(), and SCIPerrorMessage.

Referenced by applyFixings(), chgRhsLinearCons(), fixDiscreteVars(), readRanges(), readRhs(), SCIP_DECL_PRESOLEXEC(), SCIPapplyHeurDualval(), SCIPapplyProximity(), and tryUpgradingSetppc().

int SCIPgetNVarsLinear	(	SCIP *	scip,
		SCIP_CONS *	cons
	)

gets the number of variables in the linear constraint

Parameters

scip	SCIP data structure
cons	constraint data

Definition at line 16768 of file cons_linear.c.

Referenced by addAltLPConstraint(), addLinearConstraints(), checkLinearConssVarboundSOS1(), extractLinearValues(), getLinearConsNVars(), getLinearConsVarsData(), propIndicator(), readIndicators(), readNonlinearExprs(), readQCMatrix(), readQuadraticCoefs(), SCIP_DECL_CONSLOCK(), SCIP_DECL_CONSPRESOL(), SCIP_DECL_PARAMCHGD(), SCIP_DECL_READERWRITE(), SCIPcreateConsIndicatorLinCons(), SCIPmakeIndicatorFeasible(), SCIPmatrixCreate(), SCIPsetLinearConsIndicator(), SCIPwriteCcg(), SCIPwriteGms(), SCIPwriteLp(), SCIPwritePbm(), SCIPwritePip(), SCIPwritePpm(), tightenVarsBoundsSOS1(), upgradeIndicatorSuperindicator(), upgradeLinearSuperindicator(), writeFzn(), writeOpbConstraints(), and writeOpbObjective().

SCIP_VAR** SCIPgetVarsLinear	(	SCIP *	scip,
		SCIP_CONS *	cons
	)

gets the array of variables in the linear constraint; the user must not modify this array!

Parameters

scip	SCIP data structure
cons	constraint data

Definition at line 16792 of file cons_linear.c.

Referenced by addAltLPConstraint(), addLinearConstraints(), checkLinearConssVarboundSOS1(), extractLinearValues(), getLinearConsVarsData(), propIndicator(), readIndicators(), readNonlinearExprs(), readQCMatrix(), readQuadraticCoefs(), SCIP_DECL_CONSLOCK(), SCIP_DECL_CONSPRESOL(), SCIP_DECL_PARAMCHGD(), SCIP_DECL_READERWRITE(), SCIPcreateConsIndicatorLinCons(), SCIPmakeIndicatorFeasible(), SCIPmatrixCreate(), SCIPsetLinearConsIndicator(), SCIPwriteCcg(), SCIPwriteGms(), SCIPwriteLp(), SCIPwritePbm(), SCIPwritePip(), SCIPwritePpm(), tightenVarsBoundsSOS1(), upgradeIndicatorSuperindicator(), upgradeLinearSuperindicator(), writeFzn(), writeOpbConstraints(), and writeOpbObjective().

SCIP_Real* SCIPgetValsLinear	(	SCIP *	scip,
		SCIP_CONS *	cons
	)

gets the array of coefficient values in the linear constraint; the user must not modify this array!

Parameters

scip	SCIP data structure
cons	constraint data

Definition at line 16816 of file cons_linear.c.

Referenced by addAltLPConstraint(), addLinearConstraints(), checkLinearConssVarboundSOS1(), extractLinearValues(), getLinearConsVarsData(), propIndicator(), readIndicators(), readNonlinearExprs(), readQCMatrix(), readQuadraticCoefs(), SCIP_DECL_CONSLOCK(), SCIP_DECL_CONSPRESOL(), SCIP_DECL_PARAMCHGD(), SCIP_DECL_READERWRITE(), SCIPmakeIndicatorFeasible(), SCIPmatrixCreate(), SCIPwriteCcg(), SCIPwriteGms(), SCIPwriteLp(), SCIPwritePbm(), SCIPwritePip(), SCIPwritePpm(), tightenVarsBoundsSOS1(), upgradeIndicatorSuperindicator(), upgradeLinearSuperindicator(), writeFzn(), and writeOpbConstraints().

SCIP_Real SCIPgetActivityLinear	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_SOL *	sol
	)

gets the activity of the linear constraint in the given solution

Note: if the solution contains values at infinity, this method will return SCIP_INVALID in case the activity comprises positive and negative infinity contributions

Parameters

scip	SCIP data structure
cons	constraint data
sol	solution, or NULL to use current node's solution

Definition at line 16844 of file cons_linear.c.

SCIP_Real SCIPgetFeasibilityLinear	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_SOL *	sol
	)

gets the feasibility of the linear constraint in the given solution

Parameters

scip	SCIP data structure
cons	constraint data
sol	solution, or NULL to use current node's solution

Definition at line 16872 of file cons_linear.c.

SCIP_Real SCIPgetDualsolLinear	(	SCIP *	scip,
		SCIP_CONS *	cons
	)

gets the dual solution of the linear constraint in the current LP

Parameters

scip	SCIP data structure
cons	constraint data

Definition at line 16900 of file cons_linear.c.

Referenced by printDualSol(), and SCIP_DECL_EVENTEXEC().

SCIP_Real SCIPgetDualfarkasLinear	(	SCIP *	scip,
		SCIP_CONS *	cons
	)

gets the dual Farkas value of the linear constraint in the current infeasible LP

Parameters

scip	SCIP data structure
cons	constraint data

Definition at line 16927 of file cons_linear.c.

SCIP_ROW* SCIPgetRowLinear	(	SCIP *	scip,
		SCIP_CONS *	cons
	)

returns the linear relaxation of the given linear constraint; may return NULL if no LP row was yet created; the user must not modify the row!

Parameters

scip	SCIP data structure
cons	constraint data

Definition at line 16956 of file cons_linear.c.

SCIP_RETCODE SCIPupgradeConsLinear	(	SCIP *	scip,
		SCIP_CONS *	cons,
		SCIP_CONS **	upgdcons
	)

tries to automatically convert a linear constraint into a more specific and more specialized constraint

Parameters

scip	SCIP data structure
cons	source constraint to try to convert
upgdcons	pointer to store upgraded constraint, or NULL if not successful

Definition at line 16980 of file cons_linear.c.

SCIP

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