Detailed Description

DINS primal heuristic (according to Ghosh).

Author: Timo Berthold; Robert Waniek

Definition in file heur_dins.c.

#include "blockmemshell/memory.h"
#include "scip/cons_linear.h"
#include "scip/heur_dins.h"
#include "scip/heuristics.h"
#include "scip/pub_event.h"
#include "scip/pub_heur.h"
#include "scip/pub_message.h"
#include "scip/pub_misc.h"
#include "scip/pub_var.h"
#include "scip/scip_branch.h"
#include "scip/scip_cons.h"
#include "scip/scip_copy.h"
#include "scip/scip_event.h"
#include "scip/scip_general.h"
#include "scip/scip_heur.h"
#include "scip/scip_lp.h"
#include "scip/scip_mem.h"
#include "scip/scip_message.h"
#include "scip/scip_nodesel.h"
#include "scip/scip_numerics.h"
#include "scip/scip_param.h"
#include "scip/scip_prob.h"
#include "scip/scip_sol.h"
#include "scip/scip_solve.h"
#include "scip/scip_solvingstats.h"
#include "scip/scip_var.h"

Go to the source code of this file.

Macros
#define	HEUR_NAME "dins"
#define	HEUR_DESC "distance induced neighborhood search by Ghosh"
#define	HEUR_DISPCHAR SCIP_HEURDISPCHAR_LNS
#define	HEUR_PRIORITY -1105000
#define	HEUR_FREQ -1
#define	HEUR_FREQOFS 0
#define	HEUR_MAXDEPTH -1
#define	HEUR_TIMING SCIP_HEURTIMING_AFTERLPNODE
#define	HEUR_USESSUBSCIP TRUE
#define	DEFAULT_NODESOFS 5000LL
#define	DEFAULT_MAXNODES 5000LL
#define	DEFAULT_MINNODES 50LL
#define	DEFAULT_MINIMPROVE 0.01
#define	DEFAULT_NODESQUOT 0.05
#define	DEFAULT_LPLIMFAC 1.5
#define	DEFAULT_MINFIXINGRATE 0.3
#define	DEFAULT_NWAITINGNODES 200LL
#define	DEFAULT_NEIGHBORHOODSIZE 18
#define	DEFAULT_SOLNUM 5
#define	DEFAULT_USELPROWS FALSE
#define	DEFAULT_COPYCUTS TRUE
#define	DEFAULT_BESTSOLLIMIT 3
#define	DEFAULT_USEUCT FALSE
#define	EVENTHDLR_NAME "Dins"
#define	EVENTHDLR_DESC "LP event handler for " HEUR_NAME " heuristic"

Functions
static void	computeIntegerVariableBounds (SCIP scip, SCIP_VAR var, SCIP_Real lbptr, SCIP_Real ubptr)
static SCIP_RETCODE	determineVariableFixings (SCIP scip, SCIP_HEUR heur, SCIP_HEURDATA heurdata, SCIP_VAR vars, SCIP_VAR fixedvars, SCIP_Real fixedvals, int nbinvars, int nintvars, int binfixings, int intfixings)
static SCIP_RETCODE	reboundIntegerVariables (SCIP scip, SCIP subscip, SCIP_VAR vars, SCIP_VAR subvars, int nbinvars, int nintvars)
static SCIP_RETCODE	addLocalBranchingConstraint (SCIP scip, SCIP subscip, SCIP_VAR *subvars, SCIP_HEURDATA heurdata)
static	SCIP_DECL_EVENTEXEC (eventExecDins)
static SCIP_RETCODE	wrapperDins (SCIP scip, SCIP subscip, SCIP_HEUR heur, SCIP_HEURDATA heurdata, SCIP_VAR vars, SCIP_VAR fixedvars, SCIP_Real fixedvals, SCIP_RESULT result, int nvars, int nbinvars, int nintvars, int binfixings, int intfixings, SCIP_Longint nsubnodes)
static	SCIP_DECL_HEURCOPY (heurCopyDins)
static	SCIP_DECL_HEURFREE (heurFreeDins)
static	SCIP_DECL_HEURINITSOL (heurInitsolDins)
static	SCIP_DECL_HEUREXITSOL (heurExitsolDins)
static	SCIP_DECL_HEUREXEC (heurExecDins)
SCIP_RETCODE	SCIPincludeHeurDins (SCIP *scip)

Macro Definition Documentation

◆ HEUR_NAME

#define HEUR_NAME "dins"

Definition at line 62 of file heur_dins.c.

◆ HEUR_DESC

#define HEUR_DESC "distance induced neighborhood search by Ghosh"

Definition at line 63 of file heur_dins.c.

◆ HEUR_DISPCHAR

#define HEUR_DISPCHAR SCIP_HEURDISPCHAR_LNS

Definition at line 64 of file heur_dins.c.

◆ HEUR_PRIORITY

#define HEUR_PRIORITY -1105000

Definition at line 65 of file heur_dins.c.

◆ HEUR_FREQ

#define HEUR_FREQ -1

Definition at line 66 of file heur_dins.c.

◆ HEUR_FREQOFS

#define HEUR_FREQOFS 0

Definition at line 67 of file heur_dins.c.

◆ HEUR_MAXDEPTH

#define HEUR_MAXDEPTH -1

Definition at line 68 of file heur_dins.c.

◆ HEUR_TIMING

#define HEUR_TIMING SCIP_HEURTIMING_AFTERLPNODE

Definition at line 69 of file heur_dins.c.

◆ HEUR_USESSUBSCIP

#define HEUR_USESSUBSCIP TRUE

does the heuristic use a secondary SCIP instance?

Definition at line 70 of file heur_dins.c.

◆ DEFAULT_NODESOFS

#define DEFAULT_NODESOFS 5000LL

Definition at line 72 of file heur_dins.c.

◆ DEFAULT_MAXNODES

#define DEFAULT_MAXNODES 5000LL

Definition at line 73 of file heur_dins.c.

◆ DEFAULT_MINNODES

#define DEFAULT_MINNODES 50LL

Definition at line 74 of file heur_dins.c.

◆ DEFAULT_MINIMPROVE

#define DEFAULT_MINIMPROVE 0.01

Definition at line 75 of file heur_dins.c.

◆ DEFAULT_NODESQUOT

#define DEFAULT_NODESQUOT 0.05

Definition at line 76 of file heur_dins.c.

◆ DEFAULT_LPLIMFAC

#define DEFAULT_LPLIMFAC 1.5

Definition at line 77 of file heur_dins.c.

◆ DEFAULT_MINFIXINGRATE

#define DEFAULT_MINFIXINGRATE 0.3

Definition at line 78 of file heur_dins.c.

◆ DEFAULT_NWAITINGNODES

#define DEFAULT_NWAITINGNODES 200LL

Definition at line 79 of file heur_dins.c.

◆ DEFAULT_NEIGHBORHOODSIZE

#define DEFAULT_NEIGHBORHOODSIZE 18

Definition at line 80 of file heur_dins.c.

Referenced by SCIPincludeHeurDins(), SCIPincludeHeurFeaspump(), and SCIPincludeHeurLocalbranching().

◆ DEFAULT_SOLNUM

#define DEFAULT_SOLNUM 5

Definition at line 81 of file heur_dins.c.

Referenced by SCIPincludeHeurDins().

◆ DEFAULT_USELPROWS

#define DEFAULT_USELPROWS FALSE

Definition at line 82 of file heur_dins.c.

◆ DEFAULT_COPYCUTS

#define DEFAULT_COPYCUTS TRUE

Definition at line 84 of file heur_dins.c.

◆ DEFAULT_BESTSOLLIMIT

#define DEFAULT_BESTSOLLIMIT 3

Definition at line 87 of file heur_dins.c.

◆ DEFAULT_USEUCT

#define DEFAULT_USEUCT FALSE

Definition at line 88 of file heur_dins.c.

◆ EVENTHDLR_NAME

#define EVENTHDLR_NAME "Dins"

Definition at line 92 of file heur_dins.c.

◆ EVENTHDLR_DESC

#define EVENTHDLR_DESC "LP event handler for " HEUR_NAME " heuristic"

Definition at line 93 of file heur_dins.c.

Function Documentation

◆ computeIntegerVariableBounds()

void computeIntegerVariableBounds	(	SCIP *	scip,
		SCIP_VAR *	var,
		SCIP_Real *	lbptr,
		SCIP_Real *	ubptr )

static

compute tightened bounds for integer variables depending on how much the LP and the incumbent solution values differ

Parameters

scip	SCIP data structure of the original problem
var	the variable for which bounds should be computed
lbptr	pointer to store the lower bound in the DINS sub-SCIP
ubptr	pointer to store the upper bound in the DINS sub-SCIP

Definition at line 132 of file heur_dins.c.

References assert(), computeIntegerVariableBounds(), MAX, MIN, REALABS, SCIP_Real, SCIP_VARTYPE_INTEGER, SCIPfeasCeil(), SCIPfeasFloor(), SCIPgetBestSol(), SCIPgetSolVal(), SCIPisFeasEQ(), SCIPvarGetLbGlobal(), SCIPvarGetLPSol(), SCIPvarGetType(), SCIPvarGetUbGlobal(), SCIPvarIsImpliedIntegral(), and var.

Referenced by computeIntegerVariableBounds(), determineVariableFixings(), and reboundIntegerVariables().

◆ determineVariableFixings()

SCIP_RETCODE determineVariableFixings	(	SCIP *	scip,
		SCIP_HEUR *	heur,
		SCIP_HEURDATA *	heurdata,
		SCIP_VAR **	vars,
		SCIP_VAR **	fixedvars,
		SCIP_Real *	fixedvals,
		int	nbinvars,
		int	nintvars,
		int *	binfixings,
		int *	intfixings )

static

creates a subproblem for subscip by fixing a number of variables

Parameters

scip	SCIP data structure of the original problem
heur	DINS heuristic structure
heurdata	heuristic data structure
vars	variables of the original problem
fixedvars	array to store variables that should be fixed in the sub-SCIP
fixedvals	array to store fixing values for fixed variables
nbinvars	number of binary variables of problem and subproblem
nintvars	number of general integer variables of problem and subproblem
binfixings	pointer to store number of binary variables that should be fixed
intfixings	pointer to store number of integer variables that should be fixed

Definition at line 206 of file heur_dins.c.

References assert(), computeIntegerVariableBounds(), determineVariableFixings(), heurdata, i, MIN, nsolsfound, NULL, SCIP_Bool, SCIP_CALL, SCIP_Longint, SCIP_OKAY, SCIP_Real, SCIPcalcMemGrowSize(), SCIPgetBestSol(), SCIPgetNSols(), SCIPgetNSolsFound(), SCIPgetSolHeur(), SCIPgetSols(), SCIPgetSolVal(), SCIPisFeasEQ(), SCIPreallocBlockMemoryArray, SCIPvarGetLPSol(), SCIPvarGetRootSol(), TRUE, and vars.

◆ reboundIntegerVariables()

SCIP_RETCODE reboundIntegerVariables	(	SCIP *	scip,
		SCIP *	subscip,
		SCIP_VAR **	vars,
		SCIP_VAR **	subvars,
		int	nbinvars,
		int	nintvars )

static

creates a subproblem for subscip by fixing a number of variables

Parameters

scip	SCIP data structure of the original problem
subscip	SCIP data structure of the subproblem
vars	variables of the original problem
subvars	variables of the DINS sub-SCIP
nbinvars	number of binary variables of problem and subproblem
nintvars	number of general integer variables of problem and subproblem

Definition at line 336 of file heur_dins.c.

References assert(), computeIntegerVariableBounds(), i, NULL, reboundIntegerVariables(), SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIPchgVarLbGlobal(), SCIPchgVarUbGlobal(), SCIPisFeasEQ(), SCIPvarGetLbGlobal(), SCIPvarGetUbGlobal(), and vars.

Referenced by reboundIntegerVariables(), and wrapperDins().

◆ addLocalBranchingConstraint()

SCIP_RETCODE addLocalBranchingConstraint	(	SCIP *	scip,
		SCIP *	subscip,
		SCIP_VAR **	subvars,
		SCIP_HEURDATA *	heurdata )

static

create the extra constraint of local branching and add it to subscip

Parameters

scip	SCIP data structure of the original problem
subscip	SCIP data structure of the subproblem
subvars	variables of the subproblem
heurdata	heuristic's data structure

Definition at line 374 of file heur_dins.c.

References addLocalBranchingConstraint(), assert(), FALSE, heurdata, i, NULL, SCIP_CALL, SCIP_MAXSTRLEN, SCIP_OKAY, SCIP_Real, SCIP_VARTYPE_BINARY, SCIPaddCons(), SCIPallocBufferArray, SCIPcreateConsLinear(), SCIPfreeBufferArray, SCIPgetBestSol(), SCIPgetProbName(), SCIPgetSolVal(), SCIPgetVarsData(), SCIPisFeasEQ(), SCIPisFeasIntegral(), SCIPreleaseCons(), SCIPsnprintf(), SCIPvarGetLbGlobal(), SCIPvarGetType(), SCIPvarGetUbGlobal(), SCIPvarIsImpliedIntegral(), TRUE, and vars.

◆ SCIP_DECL_EVENTEXEC()

SCIP_DECL_EVENTEXEC ( eventExecDins )

static

Definition at line 670 of file heur_dins.c.

References assert(), EVENTHDLR_NAME, heurdata, NULL, SCIP_CALL, SCIP_DECL_EVENTEXEC, SCIP_EVENTTYPE_LPSOLVED, SCIP_INVALIDCALL, SCIP_LONGINT_FORMAT, SCIP_OKAY, SCIP_STRINGEQ, SCIPdebugMsg, SCIPeventGetType(), SCIPeventhdlrGetName(), SCIPgetNLPs(), and SCIPinterruptSolve().

◆ wrapperDins()

SCIP_RETCODE wrapperDins	(	SCIP *	scip,
		SCIP *	subscip,
		SCIP_HEUR *	heur,
		SCIP_HEURDATA *	heurdata,
		SCIP_VAR **	vars,
		SCIP_VAR **	fixedvars,
		SCIP_Real *	fixedvals,
		SCIP_RESULT *	result,
		int	nvars,
		int	nbinvars,
		int	nintvars,
		int	binfixings,
		int	intfixings,
		SCIP_Longint	nsubnodes )

static

wrapper for the part of heuristic that runs a subscip. Wrapper is needed to avoid possible ressource leaks

Parameters

scip	original SCIP data structure
subscip	SCIP structure of the subproblem
heur	Heuristic pointer
heurdata	Heuristic's data
vars	original problem's variables
fixedvars	Fixed variables of original SCIP
fixedvals	Fixed values of original SCIP
result	Result pointer
nvars	Number of variables
nbinvars	Number of binary variables in original SCIP
nintvars	Number of integer variables in original SCIP
binfixings	Number of binary fixing in original SCIP
intfixings	Number of integer fixings in original SCIP
nsubnodes	Number of nodes in the subscip

Definition at line 456 of file heur_dins.c.

References addLocalBranchingConstraint(), assert(), cutoff, EVENTHDLR_DESC, EVENTHDLR_NAME, FALSE, HEUR_NAME, heurdata, i, MAX, MIN, NULL, nvars, reboundIntegerVariables(), result, SCIP_Bool, SCIP_CALL, SCIP_CALL_ABORT, SCIP_EVENTTYPE_LPSOLVED, SCIP_FOUNDSOL, SCIP_Longint, SCIP_LONGINT_FORMAT, SCIP_OKAY, SCIP_PARAMSETTING_FAST, SCIP_PARAMSETTING_OFF, SCIP_PLUGINNOTFOUND, SCIP_Real, SCIPallocBufferArray, SCIPblkmem(), SCIPcatchEvent(), SCIPcopyLargeNeighborhoodSearch(), SCIPcopyLimits(), SCIPdebug, SCIPdebugMsg, SCIPdropEvent(), SCIPerrorMessage, SCIPfindBranchrule(), SCIPfindNodesel(), SCIPfreeBufferArray, SCIPgetLowerbound(), SCIPgetNBinVars(), SCIPgetNConss(), SCIPgetNIntVars(), SCIPgetNNodes(), SCIPgetNSols(), SCIPgetNVars(), SCIPgetUpperbound(), SCIPhashmapCreate(), SCIPhashmapFree(), SCIPhashmapGetImage(), SCIPincludeEventhdlrBasic(), SCIPisInfinity(), SCIPisParamFixed(), SCIPprintStatistics(), SCIPsetBoolParam(), SCIPsetCharParam(), SCIPsetIntParam(), SCIPsetLongintParam(), SCIPsetObjlimit(), SCIPsetPresolving(), SCIPsetSeparating(), SCIPsetSubscipsOff(), SCIPsolve(), SCIPsumepsilon(), SCIPtransformProb(), SCIPtranslateSubSols(), TRUE, vars, and wrapperDins().

Referenced by SCIP_DECL_HEUREXEC(), and wrapperDins().

◆ SCIP_DECL_HEURCOPY()

SCIP_DECL_HEURCOPY ( heurCopyDins )

static

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

Definition at line 701 of file heur_dins.c.

References assert(), HEUR_NAME, NULL, SCIP_CALL, SCIP_DECL_HEURCOPY, SCIP_INVALIDCALL, SCIP_OKAY, SCIP_STRINGEQ, SCIPheurGetName(), and SCIPincludeHeurDins().

◆ SCIP_DECL_HEURFREE()

SCIP_DECL_HEURFREE ( heurFreeDins )

static

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

Definition at line 716 of file heur_dins.c.

References assert(), heurdata, NULL, SCIP_DECL_HEURFREE, SCIP_OKAY, SCIPfreeBlockMemory, SCIPheurGetData(), and SCIPheurSetData().

◆ SCIP_DECL_HEURINITSOL()

SCIP_DECL_HEURINITSOL ( heurInitsolDins )

static

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

Definition at line 737 of file heur_dins.c.

References assert(), heurdata, i, NULL, SCIP_CALL, SCIP_DECL_HEURINITSOL, SCIP_OKAY, SCIPallocBlockMemoryArray, SCIPgetNBinVars(), SCIPheurGetData(), and TRUE.

◆ SCIP_DECL_HEUREXITSOL()

SCIP_DECL_HEUREXITSOL ( heurExitsolDins )

static

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

Definition at line 768 of file heur_dins.c.

References assert(), heurdata, NULL, SCIP_DECL_HEUREXITSOL, SCIP_OKAY, SCIPfreeBlockMemoryArray, and SCIPheurGetData().

◆ SCIP_DECL_HEUREXEC()

SCIP_DECL_HEUREXEC ( heurExecDins )

static

execution method of primal heuristic

Definition at line 789 of file heur_dins.c.

References assert(), determineVariableFixings(), heurdata, MAX, MIN, NULL, nvars, result, SCIP_Bool, SCIP_CALL, SCIP_DECL_HEUREXEC, SCIP_DELAYED, SCIP_DIDNOTFIND, SCIP_DIDNOTRUN, SCIP_Longint, SCIP_LPSOLSTAT_OPTIMAL, SCIP_OKAY, SCIP_Real, SCIPallocBufferArray, SCIPcheckCopyLimits(), SCIPcreate(), SCIPfree(), SCIPfreeBufferArray, SCIPgetBestSol(), SCIPgetCutoffbound(), SCIPgetLPObjval(), SCIPgetLPSolstat(), SCIPgetNNodes(), SCIPgetNSols(), SCIPgetSolNodenum(), SCIPgetVarsData(), SCIPhasCurrentNodeLP(), SCIPheurGetData(), SCIPheurGetNBestSolsFound(), SCIPheurGetNCalls(), SCIPisGE(), SCIPisStopped(), vars, and wrapperDins().

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_NODESOFS

◆ DEFAULT_MAXNODES

◆ DEFAULT_MINNODES

◆ DEFAULT_MINIMPROVE

◆ DEFAULT_NODESQUOT

◆ DEFAULT_LPLIMFAC

◆ DEFAULT_MINFIXINGRATE

◆ DEFAULT_NWAITINGNODES

◆ DEFAULT_NEIGHBORHOODSIZE

◆ DEFAULT_SOLNUM

◆ DEFAULT_USELPROWS

◆ DEFAULT_COPYCUTS

◆ DEFAULT_BESTSOLLIMIT

◆ DEFAULT_USEUCT

◆ EVENTHDLR_NAME

◆ EVENTHDLR_DESC

Function Documentation

◆ computeIntegerVariableBounds()

◆ determineVariableFixings()

◆ reboundIntegerVariables()

◆ addLocalBranchingConstraint()

◆ SCIP_DECL_EVENTEXEC()

◆ wrapperDins()

◆ SCIP_DECL_HEURCOPY()

◆ SCIP_DECL_HEURFREE()

◆ SCIP_DECL_HEURINITSOL()

◆ SCIP_DECL_HEUREXITSOL()

◆ SCIP_DECL_HEUREXEC()