Detailed Description

improvement heuristic that alters single variable values

Author: Timo Berthold

Definition in file heur_oneopt.c.

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

Macros
#define	HEUR_NAME "oneopt"

#define	HEUR_DESC "1-opt heuristic which tries to improve setting of single integer variables"

#define	HEUR_DISPCHAR 'b'

#define	HEUR_PRIORITY -20000

#define	HEUR_FREQ 1

#define	HEUR_FREQOFS 0

#define	HEUR_MAXDEPTH -1

#define	HEUR_TIMING SCIP_HEURTIMING_BEFOREPRESOL \| SCIP_HEURTIMING_AFTERNODE

#define	HEUR_USESSUBSCIP FALSE

#define	DEFAULT_WEIGHTEDOBJ TRUE

#define	DEFAULT_DURINGROOT TRUE

#define	DEFAULT_BEFOREPRESOL FALSE

#define	DEFAULT_FORCELPCONSTRUCTION FALSE

#define	DEFAULT_USELOOP TRUE

Functions
static SCIP_RETCODE	createNewSol (SCIP scip, SCIP subscip, SCIP_VAR *subvars, SCIP_HEUR heur, SCIP_SOL subsol, SCIP_Bool success)

static SCIP_Real	calcShiftVal (SCIP scip, SCIP_VAR var, SCIP_Real solval, SCIP_Real *activities)

static SCIP_RETCODE	updateRowActivities (SCIP scip, SCIP_Real activities, SCIP_VAR *var, SCIP_Real shiftval)

static	SCIP_DECL_HEURCOPY (heurCopyOneopt)

static	SCIP_DECL_HEURFREE (heurFreeOneopt)

static	SCIP_DECL_HEURINITSOL (heurInitsolOneopt)

static	SCIP_DECL_HEUREXITSOL (heurExitsolOneopt)

static	SCIP_DECL_HEURINIT (heurInitOneopt)

static	SCIP_DECL_HEUREXEC (heurExecOneopt)

SCIP_RETCODE	SCIPincludeHeurOneopt (SCIP *scip)

Macro Definition Documentation

◆ HEUR_NAME

#define HEUR_NAME "oneopt"

Definition at line 32 of file heur_oneopt.c.

Referenced by SCIP_DECL_HEURCOPY(), SCIP_DECL_HEUREXITSOL(), SCIP_DECL_HEURFREE(), SCIP_DECL_HEURINITSOL(), and SCIPincludeHeurOneopt().

◆ HEUR_DESC

#define HEUR_DESC "1-opt heuristic which tries to improve setting of single integer variables"

Definition at line 33 of file heur_oneopt.c.

Referenced by SCIPincludeHeurOneopt().

◆ HEUR_DISPCHAR

#define HEUR_DISPCHAR 'b'

Definition at line 34 of file heur_oneopt.c.

Referenced by SCIPincludeHeurOneopt().

◆ HEUR_PRIORITY

#define HEUR_PRIORITY -20000

Definition at line 35 of file heur_oneopt.c.

Referenced by SCIPincludeHeurOneopt().

◆ HEUR_FREQ

#define HEUR_FREQ 1

Definition at line 36 of file heur_oneopt.c.

Referenced by SCIPincludeHeurOneopt().

◆ HEUR_FREQOFS

#define HEUR_FREQOFS 0

Definition at line 37 of file heur_oneopt.c.

Referenced by SCIPincludeHeurOneopt().

◆ HEUR_MAXDEPTH

#define HEUR_MAXDEPTH -1

Definition at line 38 of file heur_oneopt.c.

Referenced by SCIPincludeHeurOneopt().

◆ HEUR_TIMING

#define HEUR_TIMING SCIP_HEURTIMING_BEFOREPRESOL | SCIP_HEURTIMING_AFTERNODE

Definition at line 39 of file heur_oneopt.c.

Referenced by SCIP_DECL_HEUREXEC(), SCIP_DECL_HEUREXITSOL(), and SCIPincludeHeurOneopt().

◆ HEUR_USESSUBSCIP

#define HEUR_USESSUBSCIP FALSE

does the heuristic use a secondary SCIP instance?

Definition at line 40 of file heur_oneopt.c.

Referenced by SCIPincludeHeurOneopt().

◆ DEFAULT_WEIGHTEDOBJ

#define DEFAULT_WEIGHTEDOBJ TRUE

should the objective be weighted with the potential shifting value when sorting the shifting candidates?

Definition at line 42 of file heur_oneopt.c.

Referenced by SCIPincludeHeurOneopt().

◆ DEFAULT_DURINGROOT

#define DEFAULT_DURINGROOT TRUE

should the heuristic be called before and during the root node?

Definition at line 43 of file heur_oneopt.c.

Referenced by SCIPincludeHeurOneopt().

◆ DEFAULT_BEFOREPRESOL

#define DEFAULT_BEFOREPRESOL FALSE

should the heuristic be called before presolving

Definition at line 44 of file heur_oneopt.c.

Referenced by SCIPincludeHeurOneopt().

◆ DEFAULT_FORCELPCONSTRUCTION

#define DEFAULT_FORCELPCONSTRUCTION FALSE

should the construction of the LP be forced even if LP solving is deactivated?

Definition at line 45 of file heur_oneopt.c.

Referenced by SCIPincludeHeurOneopt().

◆ DEFAULT_USELOOP

#define DEFAULT_USELOOP TRUE

should the heuristic continue to run as long as improvements are found?

Definition at line 46 of file heur_oneopt.c.

Referenced by SCIPincludeHeurOneopt().

Function Documentation

◆ createNewSol()

static SCIP_RETCODE createNewSol	(	SCIP *	scip,
		SCIP *	subscip,
		SCIP_VAR **	subvars,
		SCIP_HEUR *	heur,
		SCIP_SOL *	subsol,
		SCIP_Bool *	success
	)

static

creates a new solution for the original problem by copying the solution of the subproblem

Parameters

scip	original SCIP data structure
subscip	SCIP structure of the subproblem
subvars	the variables of the subproblem
heur	zeroobj heuristic structure
subsol	solution of the subproblem
success	used to store whether new solution was found or not

Definition at line 69 of file heur_oneopt.c.

References FALSE, NULL, SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIPallocBufferArray, SCIPcreateSol(), SCIPfreeBufferArray, SCIPgetNOrigVars(), SCIPgetSolVals(), SCIPgetVarsData(), SCIPsetSolVals(), SCIPtrySolFree(), and TRUE.

Referenced by SCIP_DECL_HEUREXEC().

◆ calcShiftVal()

static SCIP_Real calcShiftVal	(	SCIP *	scip,
		SCIP_VAR *	var,
		SCIP_Real	solval,
		SCIP_Real *	activities
	)

static

compute value by which the solution of variable var can be shifted

Parameters

scip	SCIP data structure
var	variable that should be shifted
solval	current solution value
activities	LP row activities

Definition at line 115 of file heur_oneopt.c.

References FALSE, MAX, MIN, NULL, SCIP_Bool, SCIP_Real, SCIPcolGetNLPNonz(), SCIPcolGetRows(), SCIPcolGetVals(), SCIPdebugMsg, SCIPfeasFloor(), SCIPgetNLPRows(), SCIPisFeasGE(), SCIPisFeasLE(), SCIPisInfinity(), SCIProwGetLhs(), SCIProwGetLPPos(), SCIProwGetName(), SCIProwGetRhs(), SCIProwIsInLP(), SCIProwIsLocal(), SCIPvarGetCol(), SCIPvarGetLbGlobal(), SCIPvarGetName(), SCIPvarGetObj(), SCIPvarGetUbGlobal(), and TRUE.

Referenced by SCIP_DECL_HEUREXEC().

◆ updateRowActivities()

static SCIP_RETCODE updateRowActivities	(	SCIP *	scip,
		SCIP_Real *	activities,
		SCIP_VAR *	var,
		SCIP_Real	shiftval
	)

static

update row activities after a variable's solution value changed

Parameters

scip	SCIP data structure
activities	LP row activities
var	variable that has been changed
shiftval	value that is added to variable

Definition at line 213 of file heur_oneopt.c.

References NULL, SCIP_OKAY, SCIP_Real, SCIPcolGetNLPNonz(), SCIPcolGetRows(), SCIPcolGetVals(), SCIPgetNLPRows(), SCIPinfinity(), SCIPisInfinity(), SCIProwGetLPPos(), SCIProwIsLocal(), and SCIPvarGetCol().

Referenced by SCIP_DECL_HEUREXEC().

◆ SCIP_DECL_HEURCOPY()

static SCIP_DECL_HEURCOPY ( heurCopyOneopt )

static

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

Definition at line 267 of file heur_oneopt.c.

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

◆ SCIP_DECL_HEURFREE()

static SCIP_DECL_HEURFREE ( heurFreeOneopt )

static

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

Definition at line 281 of file heur_oneopt.c.

References HEUR_NAME, NULL, SCIP_OKAY, SCIPfreeBlockMemory, SCIPheurGetData(), SCIPheurGetName(), and SCIPheurSetData().

◆ SCIP_DECL_HEURINITSOL()

static SCIP_DECL_HEURINITSOL ( heurInitsolOneopt )

static

solving process initialization method of primal heuristic (called when branch and bound process is about to begin)

Definition at line 301 of file heur_oneopt.c.

References HEUR_NAME, NULL, SCIP_HEURTIMING_BEFORENODE, SCIP_HEURTIMING_DURINGLPLOOP, SCIP_OKAY, SCIPheurGetData(), SCIPheurGetFreqofs(), SCIPheurGetName(), and SCIPheurSetTimingmask().

◆ SCIP_DECL_HEUREXITSOL()

static SCIP_DECL_HEUREXITSOL ( heurExitsolOneopt )

static

solving process deinitialization method of primal heuristic (called before branch and bound process data is freed)

Definition at line 320 of file heur_oneopt.c.

References HEUR_NAME, HEUR_TIMING, NULL, SCIP_OKAY, SCIPheurGetName(), and SCIPheurSetTimingmask().

◆ SCIP_DECL_HEURINIT()

static SCIP_DECL_HEURINIT ( heurInitOneopt )

static

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

Definition at line 333 of file heur_oneopt.c.

References NULL, SCIP_OKAY, and SCIPheurGetData().

◆ SCIP_DECL_HEUREXEC()

static SCIP_DECL_HEUREXEC ( heurExecOneopt )

static

execution method of primal heuristic

Definition at line 353 of file heur_oneopt.c.

References calcShiftVal(), createNewSol(), FALSE, HEUR_TIMING, NULL, SCIP_Bool, SCIP_CALL, SCIP_CALL_ABORT, SCIP_DELAYED, SCIP_DIDNOTFIND, SCIP_DIDNOTRUN, SCIP_FOUNDSOL, SCIP_HEURTIMING_BEFORENODE, SCIP_HEURTIMING_BEFOREPRESOL, SCIP_LPSOLSTAT_OPTIMAL, SCIP_OKAY, SCIP_PARAMSETTING_OFF, SCIP_Real, SCIP_VARSTATUS_COLUMN, SCIPallocBufferArray, SCIPblkmem(), SCIPcheckCopyLimits(), SCIPchgVarLbDive(), SCIPchgVarUbDive(), SCIPconstructLP(), SCIPcopy(), SCIPcopyLimits(), SCIPcreate(), SCIPcreateOrigSol(), SCIPcreateSolCopy(), SCIPcutoffNode(), SCIPdebug, SCIPdebugMsg, SCIPendDive(), SCIPflushLP(), SCIPfree(), SCIPfreeBufferArray, SCIPfreeSol(), SCIPgetBestSol(), SCIPgetCurrentNode(), SCIPgetLPRowsData(), SCIPgetLPSolstat(), SCIPgetNLPIterations(), SCIPgetNLPRows(), SCIPgetNNodes(), SCIPgetNSols(), SCIPgetRowSolActivity(), SCIPgetSols(), SCIPgetSolVal(), SCIPgetSolVals(), SCIPgetVarsData(), SCIPhasCurrentNodeLP(), SCIPhashmapCreate(), SCIPhashmapFree(), SCIPhashmapGetImage(), SCIPheurGetData(), SCIPheurSetTimingmask(), SCIPisFeasGE(), SCIPisFeasGT(), SCIPisFeasLE(), SCIPisFeasLT(), SCIPisFeasZero(), SCIPisParamFixed(), SCIPlinkLPSol(), SCIPprintRow(), SCIPprintSol(), SCIPprintStatistics(), SCIPreallocBufferArray, SCIProwGetLhs(), SCIProwGetLPPos(), SCIProwGetName(), SCIProwGetRhs(), SCIProwIsLocal(), SCIPsetBoolParam(), SCIPsetHeuristics(), SCIPsetIntParam(), SCIPsetLongintParam(), SCIPsetPresolving(), SCIPsetSeparating(), SCIPsetSolVal(), SCIPsetSolVals(), SCIPsolGetIndex(), SCIPsolIsOriginal(), SCIPsolSetHeur(), SCIPsolve(), SCIPsolveDiveLP(), SCIPsortRealPtr(), SCIPstartDive(), SCIPtransformProb(), SCIPtrySol(), SCIPtrySolFree(), SCIPunfixParam(), SCIPvarGetLbGlobal(), SCIPvarGetName(), SCIPvarGetObj(), SCIPvarGetStatus(), SCIPvarGetType(), SCIPvarGetUbGlobal(), SCIPwarningMessage(), TRUE, and updateRowActivities().

SCIP

Detailed Description

Macros

Functions

Macro Definition Documentation

◆ HEUR_NAME

◆ HEUR_DESC

◆ HEUR_DISPCHAR

◆ HEUR_PRIORITY

◆ HEUR_FREQ

◆ HEUR_FREQOFS

◆ HEUR_MAXDEPTH

◆ HEUR_TIMING

◆ HEUR_USESSUBSCIP

◆ DEFAULT_WEIGHTEDOBJ

◆ DEFAULT_DURINGROOT

◆ DEFAULT_BEFOREPRESOL

◆ DEFAULT_FORCELPCONSTRUCTION

◆ DEFAULT_USELOOP

Function Documentation

◆ createNewSol()

◆ calcShiftVal()

◆ updateRowActivities()

◆ SCIP_DECL_HEURCOPY()

◆ SCIP_DECL_HEURFREE()

◆ SCIP_DECL_HEURINITSOL()

◆ SCIP_DECL_HEUREXITSOL()

◆ SCIP_DECL_HEURINIT()

◆ SCIP_DECL_HEUREXEC()