Scippy

SCIP

Solving Constraint Integer Programs

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Detailed Description

fix-and-infer primal heuristic

Author: Tobias Achterberg

Definition in file heur_fixandinfer.c.

#include <assert.h>
#include <string.h>
#include "scip/heur_fixandinfer.h"

Go to the source code of this file.

Macros
#define	HEUR_NAME "fixandinfer"

#define	HEUR_DESC "iteratively fixes variables and propagates inferences"

#define	HEUR_DISPCHAR 'I'

#define	HEUR_PRIORITY -500000

#define	HEUR_FREQ -1 /* at the moment, the heuristic seems to be useless */

#define	HEUR_FREQOFS 0

#define	HEUR_MAXDEPTH -1

#define	HEUR_TIMING SCIP_HEURTIMING_AFTERNODE

#define	HEUR_USESSUBSCIP FALSE

#define	MAXDIVEDEPTH 100

#define	DEFAULT_PROPROUNDS 0

#define	DEFAULT_MINFIXINGS 100

Functions
static SCIP_RETCODE	fixVariable (SCIP scip, SCIP_VAR *pseudocands, int npseudocands, SCIP_Real large)

static	SCIP_DECL_HEURCOPY (heurCopyFixandinfer)

static	SCIP_DECL_HEURFREE (heurFreeFixandinfer)

static	SCIP_DECL_HEUREXEC (heurExecFixandinfer)

SCIP_RETCODE	SCIPincludeHeurFixandinfer (SCIP *scip)

Macro Definition Documentation

#define HEUR_NAME "fixandinfer"

Definition at line 29 of file heur_fixandinfer.c.

Referenced by SCIP_DECL_HEURCOPY(), and SCIPincludeHeurFixandinfer().

#define HEUR_DESC "iteratively fixes variables and propagates inferences"

Definition at line 30 of file heur_fixandinfer.c.

Referenced by SCIPincludeHeurFixandinfer().

#define HEUR_DISPCHAR 'I'

Definition at line 31 of file heur_fixandinfer.c.

Referenced by SCIPincludeHeurFixandinfer().

#define HEUR_PRIORITY -500000

Definition at line 32 of file heur_fixandinfer.c.

Referenced by SCIPincludeHeurFixandinfer().

#define HEUR_FREQ -1 /* at the moment, the heuristic seems to be useless */

Definition at line 33 of file heur_fixandinfer.c.

Referenced by SCIPincludeHeurFixandinfer().

#define HEUR_FREQOFS 0

Definition at line 34 of file heur_fixandinfer.c.

Referenced by SCIPincludeHeurFixandinfer().

#define HEUR_MAXDEPTH -1

Definition at line 35 of file heur_fixandinfer.c.

Referenced by SCIPincludeHeurFixandinfer().

#define HEUR_TIMING SCIP_HEURTIMING_AFTERNODE

Definition at line 36 of file heur_fixandinfer.c.

Referenced by SCIPincludeHeurFixandinfer().

#define HEUR_USESSUBSCIP FALSE

does the heuristic use a secondary SCIP instance?

Definition at line 37 of file heur_fixandinfer.c.

Referenced by SCIPincludeHeurFixandinfer().

#define MAXDIVEDEPTH 100

Definition at line 39 of file heur_fixandinfer.c.

Referenced by SCIP_DECL_HEUREXEC().

#define DEFAULT_PROPROUNDS 0

maximal number of propagation rounds in probing subproblems

Definition at line 46 of file heur_fixandinfer.c.

Referenced by SCIPincludeHeurFixandinfer().

#define DEFAULT_MINFIXINGS 100

minimal number of fixings to apply before dive may be aborted

Definition at line 47 of file heur_fixandinfer.c.

Referenced by SCIPincludeHeurFixandinfer().

Function Documentation

static SCIP_RETCODE fixVariable	(	SCIP *	scip,
		SCIP_VAR **	pseudocands,
		int	npseudocands,
		SCIP_Real	large
	)

static

selects a variable and fixes it to its current pseudo solution value

Parameters

scip	SCIP data structure
pseudocands	array of unfixed variables
npseudocands	number of unfixed variables
large	large value to be used instead of infinity

Definition at line 68 of file heur_fixandinfer.c.

References NULL, SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIPceil(), SCIPdebugMessage, SCIPfixVarProbing(), SCIPfloor(), SCIPgetNPrioPseudoBranchBins(), SCIPgetVarAvgInferenceScore(), SCIPgetVarSol(), SCIPinfinity(), SCIPisFeasIntegral(), SCIPisInfinity(), SCIPvarGetLbLocal(), SCIPvarGetName(), and SCIPvarGetUbLocal().

Referenced by SCIP_DECL_HEUREXEC().

static SCIP_DECL_HEURCOPY ( heurCopyFixandinfer )

static

copy method for primal heuristic plugins (called when SCIP copies plugins)

Definition at line 152 of file heur_fixandinfer.c.

References HEUR_NAME, NULL, SCIP_CALL, SCIP_OKAY, SCIPheurGetName(), and SCIPincludeHeurFixandinfer().

static SCIP_DECL_HEURFREE ( heurFreeFixandinfer )

static

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

Definition at line 166 of file heur_fixandinfer.c.

References NULL, SCIP_OKAY, SCIPfreeMemory, SCIPheurGetData(), and SCIPheurSetData().

static SCIP_DECL_HEUREXEC ( heurExecFixandinfer )

static

execution method of primal heuristic

Definition at line 182 of file heur_fixandinfer.c.

References FALSE, fixVariable(), MAXDIVEDEPTH, NULL, SCIP_Bool, SCIP_CALL, SCIP_DIDNOTFIND, SCIP_DIDNOTRUN, SCIP_FOUNDSOL, SCIP_OKAY, SCIP_Real, SCIPdebugMessage, SCIPendProbing(), SCIPfeastol(), SCIPgetNContVars(), SCIPgetPseudoBranchCands(), SCIPheurGetData(), SCIPinfinity(), SCIPisInfinity(), SCIPisStopped(), SCIPnewProbingNode(), SCIPpropagateProbing(), SCIPstartProbing(), SCIPtryCurrentSol(), and TRUE.

SCIP_RETCODE SCIPincludeHeurFixandinfer ( SCIP * scip )

creates the fix-and-infer primal heuristic and includes it in SCIP

Parameters

scip	SCIP data structure

Definition at line 293 of file heur_fixandinfer.c.

References DEFAULT_MINFIXINGS, DEFAULT_PROPROUNDS, HEUR_DESC, HEUR_DISPCHAR, HEUR_FREQ, HEUR_FREQOFS, HEUR_MAXDEPTH, HEUR_NAME, HEUR_PRIORITY, HEUR_TIMING, HEUR_USESSUBSCIP, NULL, SCIP_CALL, SCIP_OKAY, SCIPaddIntParam(), SCIPallocMemory, SCIPincludeHeurBasic(), SCIPsetHeurCopy(), SCIPsetHeurFree(), and TRUE.

Referenced by SCIP_DECL_HEURCOPY(), and SCIPincludeDefaultPlugins().