Detailed Description

Local branching heuristic according to Fischetti and Lodi.

Author: Timo Berthold; Marc Pfetsch

Definition in file heur_localbranching.c.

#include <assert.h>
#include <string.h>
#include "scip/scip.h"
#include "scip/cons_linear.h"
#include "scip/scipdefplugins.h"
#include "scip/heur_localbranching.h"
#include "scip/pub_misc.h"

Go to the source code of this file.

Macros
#define	HEUR_NAME "localbranching"

#define	HEUR_DESC "local branching heuristic by Fischetti and Lodi"

#define	HEUR_DISPCHAR 'L'

#define	HEUR_PRIORITY -1102000

#define	HEUR_FREQ -1

#define	HEUR_FREQOFS 0

#define	HEUR_MAXDEPTH -1

#define	HEUR_TIMING SCIP_HEURTIMING_AFTERNODE

#define	HEUR_USESSUBSCIP TRUE

#define	DEFAULT_NEIGHBORHOODSIZE 18 /* radius of the incumbents neighborhood to be searched */

#define	DEFAULT_NODESOFS 1000 /* number of nodes added to the contingent of the total nodes */

#define	DEFAULT_MAXNODES 10000 /* maximum number of nodes to regard in the subproblem */

#define	DEFAULT_MINIMPROVE 0.01 /* factor by which localbranching should at least improve the incumbent */

#define	DEFAULT_MINNODES 1000 /* minimum number of nodes required to start the subproblem */

#define	DEFAULT_NODESQUOT 0.05 /* contingent of sub problem nodes in relation to original nodes */

#define	DEFAULT_LPLIMFAC 1.5 /* factor by which the limit on the number of LP depends on the node limit */

#define	DEFAULT_NWAITINGNODES 200 /* number of nodes without incumbent change that heuristic should wait */

#define	DEFAULT_USELPROWS

#define	DEFAULT_COPYCUTS

#define	DEFAULT_BESTSOLLIMIT 3 /* limit on number of improving incumbent solutions in sub-CIP */

#define	DEFAULT_USEUCT FALSE /* should uct node selection be used at the beginning of the search? */

#define	EVENTHDLR_NAME "Localbranching"

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

#define	EXECUTE 0

#define	WAITFORNEWSOL 1

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

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

static	SCIP_DECL_EVENTEXEC (eventExecLocalbranching)

static	SCIP_DECL_HEURCOPY (heurCopyLocalbranching)

static	SCIP_DECL_HEURFREE (heurFreeLocalbranching)

static	SCIP_DECL_HEURINIT (heurInitLocalbranching)

static SCIP_RETCODE	setupAndSolveSubscipLocalbranching (SCIP scip, SCIP subscip, SCIP_HEUR heur, SCIP_Longint nsubnodes, SCIP_RESULT result)

static	SCIP_DECL_HEUREXEC (heurExecLocalbranching)

SCIP_RETCODE	SCIPincludeHeurLocalbranching (SCIP *scip)

Macro Definition Documentation

◆ HEUR_NAME

#define HEUR_NAME "localbranching"

Definition at line 32 of file heur_localbranching.c.

Referenced by SCIP_DECL_HEURCOPY(), SCIPincludeHeurLocalbranching(), and setupAndSolveSubscipLocalbranching().

◆ HEUR_DESC

#define HEUR_DESC "local branching heuristic by Fischetti and Lodi"

Definition at line 33 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ HEUR_DISPCHAR

#define HEUR_DISPCHAR 'L'

Definition at line 34 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ HEUR_PRIORITY

#define HEUR_PRIORITY -1102000

Definition at line 35 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ HEUR_FREQ

#define HEUR_FREQ -1

Definition at line 36 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ HEUR_FREQOFS

#define HEUR_FREQOFS 0

Definition at line 37 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ HEUR_MAXDEPTH

#define HEUR_MAXDEPTH -1

Definition at line 38 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ HEUR_TIMING

#define HEUR_TIMING SCIP_HEURTIMING_AFTERNODE

Definition at line 39 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ HEUR_USESSUBSCIP

#define HEUR_USESSUBSCIP TRUE

does the heuristic use a secondary SCIP instance?

Definition at line 40 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ DEFAULT_NEIGHBORHOODSIZE

#define DEFAULT_NEIGHBORHOODSIZE 18 /* radius of the incumbents neighborhood to be searched */

Definition at line 42 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ DEFAULT_NODESOFS

#define DEFAULT_NODESOFS 1000 /* number of nodes added to the contingent of the total nodes */

Definition at line 43 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ DEFAULT_MAXNODES

#define DEFAULT_MAXNODES 10000 /* maximum number of nodes to regard in the subproblem */

Definition at line 44 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ DEFAULT_MINIMPROVE

#define DEFAULT_MINIMPROVE 0.01 /* factor by which localbranching should at least improve the incumbent */

Definition at line 45 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ DEFAULT_MINNODES

#define DEFAULT_MINNODES 1000 /* minimum number of nodes required to start the subproblem */

Definition at line 46 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ DEFAULT_NODESQUOT

#define DEFAULT_NODESQUOT 0.05 /* contingent of sub problem nodes in relation to original nodes */

Definition at line 47 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ DEFAULT_LPLIMFAC

#define DEFAULT_LPLIMFAC 1.5 /* factor by which the limit on the number of LP depends on the node limit */

Definition at line 48 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ DEFAULT_NWAITINGNODES

#define DEFAULT_NWAITINGNODES 200 /* number of nodes without incumbent change that heuristic should wait */

Definition at line 49 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ DEFAULT_USELPROWS

#define DEFAULT_USELPROWS

Value:

FALSE /* should subproblem be created out of the rows in the LP rows,

* otherwise, the copy constructors of the constraints handlers are used */

FALSE

#define FALSE

Definition: def.h:64

Definition at line 50 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ DEFAULT_COPYCUTS

#define DEFAULT_COPYCUTS

Value:

TRUE      /* if DEFAULT_USELPROWS is FALSE, then should all active cuts from the cutpool
                                         * of the original scip be copied to constraints of the subscip
                                         */

Definition at line 52 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ DEFAULT_BESTSOLLIMIT

#define DEFAULT_BESTSOLLIMIT 3 /* limit on number of improving incumbent solutions in sub-CIP */

Definition at line 55 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ DEFAULT_USEUCT

#define DEFAULT_USEUCT FALSE /* should uct node selection be used at the beginning of the search? */

Definition at line 56 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ EVENTHDLR_NAME

#define EVENTHDLR_NAME "Localbranching"

Definition at line 59 of file heur_localbranching.c.

Referenced by SCIP_DECL_EVENTEXEC(), and setupAndSolveSubscipLocalbranching().

◆ EVENTHDLR_DESC

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

Definition at line 60 of file heur_localbranching.c.

Referenced by setupAndSolveSubscipLocalbranching().

◆ EXECUTE

#define EXECUTE 0

Definition at line 63 of file heur_localbranching.c.

Referenced by SCIP_DECL_HEUREXEC(), and setupAndSolveSubscipLocalbranching().

◆ WAITFORNEWSOL

#define WAITFORNEWSOL 1

Definition at line 64 of file heur_localbranching.c.

Referenced by SCIP_DECL_HEUREXEC(), SCIP_DECL_HEURINIT(), and setupAndSolveSubscipLocalbranching().

Function Documentation

◆ addLocalBranchingConstraint()

static 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 104 of file heur_localbranching.c.

References FALSE, SCIP_CALL, SCIP_MAXSTRLEN, SCIP_OKAY, SCIP_Real, SCIP_VARTYPE_BINARY, SCIPaddCons(), SCIPallocBufferArray, SCIPcreateConsLinear(), SCIPfreeBufferArray, SCIPgetBestSol(), SCIPgetProbName(), SCIPgetSolVal(), SCIPgetVarsData(), SCIPisFeasEQ(), SCIPisFeasIntegral(), SCIPreleaseCons(), SCIPsnprintf(), SCIPvarGetType(), and TRUE.

Referenced by setupAndSolveSubscipLocalbranching().

◆ 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	SCIP data structure of the original problem
subscip	SCIP data structure of the subproblem
subvars	the variables of the subproblem
heur	the Localbranching heuristic
subsol	solution of the subproblem
success	pointer to store, whether new solution was found

Definition at line 175 of file heur_localbranching.c.

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

Referenced by setupAndSolveSubscipLocalbranching().

◆ SCIP_DECL_EVENTEXEC()

static SCIP_DECL_EVENTEXEC ( eventExecLocalbranching )

static

Definition at line 225 of file heur_localbranching.c.

References EVENTHDLR_NAME, SCIP_CALL, SCIP_EVENTTYPE_LPSOLVED, SCIP_OKAY, SCIPdebugMsg, SCIPeventGetType(), SCIPeventhdlrGetName(), SCIPgetNLPs(), and SCIPinterruptSolve().

◆ SCIP_DECL_HEURCOPY()

static SCIP_DECL_HEURCOPY ( heurCopyLocalbranching )

static

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

Definition at line 255 of file heur_localbranching.c.

References HEUR_NAME, SCIP_CALL, SCIP_OKAY, SCIPheurGetName(), and SCIPincludeHeurLocalbranching().

◆ SCIP_DECL_HEURFREE()

static SCIP_DECL_HEURFREE ( heurFreeLocalbranching )

static

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

Definition at line 269 of file heur_localbranching.c.

References SCIP_OKAY, SCIPfreeBlockMemory, SCIPheurGetData(), and SCIPheurSetData().

◆ SCIP_DECL_HEURINIT()

static SCIP_DECL_HEURINIT ( heurInitLocalbranching )

static

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

Definition at line 290 of file heur_localbranching.c.

References SCIP_OKAY, SCIPheurGetData(), and WAITFORNEWSOL.

◆ setupAndSolveSubscipLocalbranching()

static SCIP_RETCODE setupAndSolveSubscipLocalbranching	(	SCIP *	scip,
		SCIP *	subscip,
		SCIP_HEUR *	heur,
		SCIP_Longint	nsubnodes,
		SCIP_RESULT *	result
	)

static

todo setup And Solve Subscip

Parameters

scip	SCIP data structure
subscip	the subproblem created by localbranching
heur	localbranching heuristic
nsubnodes	nodelimit for subscip
result	result pointer

Definition at line 314 of file heur_localbranching.c.

References addLocalBranchingConstraint(), createNewSol(), EVENTHDLR_DESC, EVENTHDLR_NAME, EXECUTE, FALSE, HEUR_NAME, MAX, SCIP_Bool, SCIP_CALL, SCIP_CALL_ABORT, SCIP_DIDNOTRUN, SCIP_EVENTTYPE_LPSOLVED, SCIP_FOUNDSOL, SCIP_OKAY, SCIP_PARAMSETTING_FAST, SCIP_PARAMSETTING_OFF, SCIP_PLUGINNOTFOUND, SCIP_Real, SCIP_STATUS_BESTSOLLIMIT, SCIP_STATUS_GAPLIMIT, SCIP_STATUS_INFEASIBLE, SCIP_STATUS_INFORUNBD, SCIP_STATUS_MEMLIMIT, SCIP_STATUS_NODELIMIT, SCIP_STATUS_OPTIMAL, SCIP_STATUS_RESTARTLIMIT, SCIP_STATUS_SOLLIMIT, SCIP_STATUS_STALLNODELIMIT, SCIP_STATUS_TIMELIMIT, SCIP_STATUS_TOTALNODELIMIT, SCIP_STATUS_UNBOUNDED, SCIP_STATUS_UNKNOWN, SCIP_STATUS_USERINTERRUPT, SCIPallocBufferArray, SCIPblkmem(), SCIPcatchEvent(), SCIPcopyLargeNeighborhoodSearch(), SCIPcopyLimits(), SCIPdebug, SCIPdebugMsg, SCIPdropEvent(), SCIPerrorMessage, SCIPfindBranchrule(), SCIPfindConshdlr(), SCIPfindNodesel(), SCIPfreeBufferArray, SCIPgetLowerbound(), SCIPgetNNodes(), SCIPgetNSols(), SCIPgetSolOrigObj(), SCIPgetSols(), SCIPgetStatus(), SCIPgetUpperbound(), SCIPgetVarsData(), SCIPhashmapCreate(), SCIPhashmapFree(), SCIPhashmapGetImage(), SCIPheurGetData(), SCIPincludeEventhdlrBasic(), SCIPisInfinity(), SCIPisParamFixed(), SCIPprintStatistics(), SCIPsetBoolParam(), SCIPsetCharParam(), SCIPsetIntParam(), SCIPsetLongintParam(), SCIPsetObjlimit(), SCIPsetPresolving(), SCIPsetSeparating(), SCIPsetSubscipsOff(), SCIPsolve(), SCIPsumepsilon(), SCIPtransformProb(), TRUE, and WAITFORNEWSOL.

Referenced by SCIP_DECL_HEUREXEC().

◆ SCIP_DECL_HEUREXEC()

static SCIP_DECL_HEUREXEC ( heurExecLocalbranching )

static

execution method of primal heuristic

Definition at line 591 of file heur_localbranching.c.

References EXECUTE, SCIP_Bool, SCIP_CALL, SCIP_DELAYED, SCIP_DIDNOTFIND, SCIP_DIDNOTRUN, SCIP_Longint, SCIP_OKAY, SCIPcheckCopyLimits(), SCIPcreate(), SCIPdebugMsg, SCIPfree(), SCIPgetBestSol(), SCIPgetNBinVars(), SCIPgetNNodes(), SCIPgetNSols(), SCIPgetSolNodenum(), SCIPheurGetData(), SCIPheurGetName(), SCIPheurGetNBestSolsFound(), SCIPheurGetNCalls(), SCIPisStopped(), SCIPsolGetHeur(), SCIPsolIsOriginal(), setupAndSolveSubscipLocalbranching(), and WAITFORNEWSOL.

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_NEIGHBORHOODSIZE

◆ DEFAULT_NODESOFS

◆ DEFAULT_MAXNODES

◆ DEFAULT_MINIMPROVE

◆ DEFAULT_MINNODES

◆ DEFAULT_NODESQUOT

◆ DEFAULT_LPLIMFAC

◆ DEFAULT_NWAITINGNODES

◆ DEFAULT_USELPROWS

◆ DEFAULT_COPYCUTS

◆ DEFAULT_BESTSOLLIMIT

◆ DEFAULT_USEUCT

◆ EVENTHDLR_NAME

◆ EVENTHDLR_DESC

◆ EXECUTE

◆ WAITFORNEWSOL

Function Documentation

◆ addLocalBranchingConstraint()

◆ createNewSol()

◆ SCIP_DECL_EVENTEXEC()

◆ SCIP_DECL_HEURCOPY()

◆ SCIP_DECL_HEURFREE()

◆ SCIP_DECL_HEURINIT()

◆ setupAndSolveSubscipLocalbranching()

◆ SCIP_DECL_HEUREXEC()