heur_indicator.c File Reference

Detailed Description

handle partial solutions for linear problems with indicators and otherwise continuous variables

Author

Marc Pfetsch

For linear problems with indicators and otherwise continuous variables, the indicator constraint handler can produce partial solutions, i.e., values for the indicator variables. This partial solution can be passed to this heuristic, which then fixes these values and solves an LP. Additionally a local search for a better solution is added.

Definition in file heur_indicator.c.

#include <assert.h>
#include <string.h>
#include "scip/scip.h"
#include "scip/heur_indicator.h"
#include "scip/cons_indicator.h"

Go to the source code of this file.

Macros
#define	HEUR_NAME   "indicator"
#define	HEUR_DESC   "indicator heuristic to create feasible solutions from values for indicator variables"
#define	HEUR_DISPCHAR   'A'
#define	HEUR_PRIORITY   -20200
#define	HEUR_FREQ   1
#define	HEUR_FREQOFS   0
#define	HEUR_MAXDEPTH   -1
#define	HEUR_TIMING   SCIP_HEURTIMING_DURINGLPLOOP
#define	HEUR_USESSUBSCIP   FALSE
#define	DEFAULT_ONEOPT   TRUE
#define	DEFAULT_IMPROVESOLS   FALSE

Functions
static SCIP_RETCODE	tryOneOpt (SCIP *scip, SCIP_HEUR *heur, SCIP_HEURDATA *heurdata, int nindconss, SCIP_CONS **indconss, SCIP_Bool *solcand, int *nfoundsols)
static SCIP_RETCODE	trySolCandidate (SCIP *scip, SCIP_HEUR *heur, SCIP_HEURDATA *heurdata, int nindconss, SCIP_CONS **indconss, SCIP_Bool *solcand, int *nfoundsols)
static	SCIP_DECL_HEURCOPY (heurCopyIndicator)
static	SCIP_DECL_HEURINIT (heurInitIndicator)
static	SCIP_DECL_HEURFREE (heurFreeIndicator)
static	SCIP_DECL_HEUREXEC (heurExecIndicator)
SCIP_RETCODE	SCIPincludeHeurIndicator (SCIP *scip)
SCIP_RETCODE	SCIPheurPassIndicator (SCIP *scip, SCIP_HEUR *heur, int nindconss, SCIP_CONS **indconss, SCIP_Bool *solcand)

Macro Definition Documentation

#define HEUR_NAME   "indicator"

Definition at line 33 of file heur_indicator.c.

Referenced by SCIP_DECL_HEURCOPY(), SCIPheurPassIndicator(), and SCIPincludeHeurIndicator().

#define HEUR_DESC   "indicator heuristic to create feasible solutions from values for indicator variables"

Definition at line 34 of file heur_indicator.c.

Referenced by SCIPincludeHeurIndicator().

#define HEUR_DISPCHAR   'A'

Definition at line 35 of file heur_indicator.c.

Referenced by SCIPincludeHeurIndicator().

#define HEUR_PRIORITY   -20200

Definition at line 36 of file heur_indicator.c.

Referenced by SCIPincludeHeurIndicator().

#define HEUR_FREQ   1

Definition at line 37 of file heur_indicator.c.

Referenced by SCIPincludeHeurIndicator().

#define HEUR_FREQOFS   0

Definition at line 38 of file heur_indicator.c.

Referenced by SCIPincludeHeurIndicator().

#define HEUR_MAXDEPTH   -1

Definition at line 39 of file heur_indicator.c.

Referenced by SCIPincludeHeurIndicator().

#define HEUR_TIMING   SCIP_HEURTIMING_DURINGLPLOOP

Definition at line 40 of file heur_indicator.c.

Referenced by SCIPincludeHeurIndicator().

#define HEUR_USESSUBSCIP   FALSE

does the heuristic use a secondary SCIP instance?

Definition at line 41 of file heur_indicator.c.

Referenced by SCIPincludeHeurIndicator().

#define DEFAULT_ONEOPT   TRUE

whether the one-opt heuristic should be started

Definition at line 43 of file heur_indicator.c.

Referenced by SCIPincludeHeurIndicator().

#define DEFAULT_IMPROVESOLS   FALSE

Try to improve other solutions by one-opt?

Definition at line 44 of file heur_indicator.c.

Referenced by SCIPincludeHeurIndicator().

Function Documentation

static SCIP_RETCODE tryOneOpt ( SCIP *  scip, SCIP_HEUR *  heur, SCIP_HEURDATA *  heurdata, int  nindconss, SCIP_CONS **  indconss, SCIP_Bool *  solcand, int *  nfoundsols  )

static

try one-opt on given solution

Parameters

scip	SCIP data structure
heur	indicator heuristic
heurdata	heuristic data
nindconss	number of indicator constraints
indconss	indicator constraints
solcand	values for indicator variables in partial solution
nfoundsols	number of solutions found

Definition at line 65 of file heur_indicator.c.

References FALSE, NULL, SCIP_Bool, SCIP_CALL, SCIP_LPSOLSTAT_OPTIMAL, SCIP_OKAY, SCIPbacktrackProbing(), SCIPchgVarLbProbing(), SCIPchgVarUbProbing(), SCIPconsIsActive(), SCIPcreateSol(), SCIPdebugMessage, SCIPendProbing(), SCIPgetBinaryVarIndicator(), SCIPgetDepth(), SCIPgetDepthLimit(), SCIPgetLPSolstat(), SCIPgetSolTransObj(), SCIPlinkLPSol(), SCIPnewProbingNode(), SCIPpropagateProbing(), SCIPsolveProbingLP(), SCIPstartProbing(), SCIPtrySolFree(), SCIPvarGetLbLocal(), SCIPvarGetUbLocal(), and TRUE.

Referenced by SCIP_DECL_HEUREXEC(), and trySolCandidate().

static SCIP_RETCODE trySolCandidate ( SCIP *  scip, SCIP_HEUR *  heur, SCIP_HEURDATA *  heurdata, int  nindconss, SCIP_CONS **  indconss, SCIP_Bool *  solcand, int *  nfoundsols  )

static

try given solution

Parameters

scip	SCIP data structure
heur	indicator heuristic
heurdata	heuristic data
nindconss	number of indicator constraints
indconss	indicator constraints
solcand	values for indicator variables in partial solution
nfoundsols	number of solutions found

Definition at line 199 of file heur_indicator.c.

References FALSE, NULL, SCIP_Bool, SCIP_CALL, SCIP_LPSOLSTAT_OPTIMAL, SCIP_OKAY, SCIPchgVarLbProbing(), SCIPchgVarUbProbing(), SCIPconsIsActive(), SCIPcreateSol(), SCIPdebugMessage, SCIPendProbing(), SCIPgetBinaryVarIndicator(), SCIPgetDepth(), SCIPgetDepthLimit(), SCIPgetLPSolstat(), SCIPgetSolTransObj(), SCIPlinkLPSol(), SCIPnewProbingNode(), SCIPprintSol(), SCIPpropagateProbing(), SCIPsolveProbingLP(), SCIPstartProbing(), SCIPtrySolFree(), SCIPvarGetLbLocal(), SCIPvarGetUbLocal(), TRUE, and tryOneOpt().

Referenced by SCIP_DECL_HEUREXEC().

static SCIP_DECL_HEURCOPY ( heurCopyIndicator  )

static

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

Definition at line 337 of file heur_indicator.c.

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

static SCIP_DECL_HEURINIT ( heurInitIndicator  )

static

initialization method of primal heuristic (called after problem was transformed)

Definition at line 351 of file heur_indicator.c.

References NULL, SCIP_OKAY, SCIPfindConshdlr(), SCIPheurGetData(), and SCIPwarningMessage().

static SCIP_DECL_HEURFREE ( heurFreeIndicator  )

static

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

Definition at line 376 of file heur_indicator.c.

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

static SCIP_DECL_HEUREXEC ( heurExecIndicator  )

static

execution method of primal heuristic

Definition at line 400 of file heur_indicator.c.

References FALSE, NULL, SCIP_Bool, SCIP_CALL, SCIP_DIDNOTFIND, SCIP_DIDNOTRUN, SCIP_FOUNDSOL, SCIP_OKAY, SCIP_Real, SCIPallocBufferArray, SCIPconshdlrGetConss(), SCIPconshdlrGetNConss(), SCIPconsIsActive(), SCIPdebugMessage, SCIPfreeBlockMemoryArray, SCIPfreeBufferArray, SCIPgetBestSol(), SCIPgetBinaryVarIndicator(), SCIPgetNBinVars(), SCIPgetNIntVars(), SCIPgetSolOrigObj(), SCIPgetSolVal(), SCIPgetSubscipDepth(), SCIPheurGetData(), SCIPisFeasIntegral(), SCIPsolGetHeur(), TRUE, tryOneOpt(), and trySolCandidate().

SCIP_RETCODE SCIPincludeHeurIndicator

(

SCIP *

scip

)

creates the indicator primal heuristic and includes it in SCIP

Parameters

scip	SCIP data structure

Definition at line 515 of file heur_indicator.c.

References DEFAULT_IMPROVESOLS, DEFAULT_ONEOPT, HEUR_DESC, HEUR_DISPCHAR, HEUR_FREQ, HEUR_FREQOFS, HEUR_MAXDEPTH, HEUR_NAME, HEUR_PRIORITY, HEUR_TIMING, HEUR_USESSUBSCIP, NULL, SCIP_CALL, SCIP_OKAY, SCIPaddBoolParam(), SCIPallocMemory, SCIPincludeHeurBasic(), SCIPsetHeurCopy(), SCIPsetHeurFree(), SCIPsetHeurInit(), and TRUE.

Referenced by SCIP_DECL_HEURCOPY(), and SCIPincludeDefaultPlugins().

SCIP_RETCODE SCIPheurPassIndicator	(	SCIP *	scip,
		SCIP_HEUR *	heur,
		int	nindconss,
		SCIP_CONS **	indconss,
		SCIP_Bool *	solcand
	)

pass partial solution for indicator variables to heuristic

Parameters

scip	SCIP data structure
heur	indicator heuristic
nindconss	number of indicator constraints
indconss	indicator constraints
solcand	values for indicator variables in partial solution

Definition at line 558 of file heur_indicator.c.

References BMScopyMemoryArray, HEUR_NAME, NULL, SCIP_CALL, SCIP_OKAY, SCIPduplicateBlockMemoryArray, SCIPfreeBlockMemoryArray, SCIPheurGetData(), and SCIPheurGetName().

Referenced by extendToCover().