Detailed Description

Local branching heuristic according to Fischetti and Lodi.

Author: Timo Berthold; Marc Pfetsch

Definition in file heur_localbranching.c.

#include "blockmemshell/memory.h"
#include "scip/cons_linear.h"
#include "scip/heuristics.h"
#include "scip/heur_localbranching.h"
#include "scip/pub_event.h"
#include "scip/pub_heur.h"
#include "scip/pub_message.h"
#include "scip/pub_misc.h"
#include "scip/pub_sol.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_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 <string.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 SCIP_HEURDISPCHAR_LNS
#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	EVENTHDLR_NAME "Localbranching"
#define	EVENTHDLR_DESC "LP event handler for " HEUR_NAME " heuristic"
#define	EXECUTE 0
#define	WAITFORNEWSOL 1

Functions
static SCIP_RETCODE	addLocalbranchingConstraintAndObjcutoff (SCIP scip, SCIP subscip, SCIP_HEUR heur, SCIP_VAR *subvars)
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 61 of file heur_localbranching.c.

◆ HEUR_DESC

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

Definition at line 62 of file heur_localbranching.c.

◆ HEUR_DISPCHAR

#define HEUR_DISPCHAR SCIP_HEURDISPCHAR_LNS

Definition at line 63 of file heur_localbranching.c.

◆ HEUR_PRIORITY

#define HEUR_PRIORITY -1102000

Definition at line 64 of file heur_localbranching.c.

◆ HEUR_FREQ

#define HEUR_FREQ -1

Definition at line 65 of file heur_localbranching.c.

◆ HEUR_FREQOFS

#define HEUR_FREQOFS 0

Definition at line 66 of file heur_localbranching.c.

◆ HEUR_MAXDEPTH

#define HEUR_MAXDEPTH -1

Definition at line 67 of file heur_localbranching.c.

◆ HEUR_TIMING

#define HEUR_TIMING SCIP_HEURTIMING_AFTERNODE

Definition at line 68 of file heur_localbranching.c.

◆ HEUR_USESSUBSCIP

#define HEUR_USESSUBSCIP TRUE

does the heuristic use a secondary SCIP instance?

Definition at line 69 of file heur_localbranching.c.

◆ DEFAULT_NEIGHBORHOODSIZE

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

Definition at line 71 of file heur_localbranching.c.

◆ DEFAULT_NODESOFS

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

Definition at line 72 of file heur_localbranching.c.

◆ DEFAULT_MAXNODES

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

Definition at line 73 of file heur_localbranching.c.

◆ DEFAULT_MINIMPROVE

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

Definition at line 74 of file heur_localbranching.c.

◆ DEFAULT_MINNODES

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

Definition at line 75 of file heur_localbranching.c.

◆ DEFAULT_NODESQUOT

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

Definition at line 76 of file heur_localbranching.c.

◆ 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 77 of file heur_localbranching.c.

◆ DEFAULT_NWAITINGNODES

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

Definition at line 78 of file heur_localbranching.c.

◆ 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:101

Definition at line 79 of file heur_localbranching.c.

◆ 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 80 of file heur_localbranching.c.

◆ DEFAULT_BESTSOLLIMIT

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

Definition at line 81 of file heur_localbranching.c.

◆ EVENTHDLR_NAME

#define EVENTHDLR_NAME "Localbranching"

Definition at line 84 of file heur_localbranching.c.

◆ EVENTHDLR_DESC

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

Definition at line 85 of file heur_localbranching.c.

◆ EXECUTE

#define EXECUTE 0

Definition at line 88 of file heur_localbranching.c.

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

◆ WAITFORNEWSOL

#define WAITFORNEWSOL 1

Definition at line 89 of file heur_localbranching.c.

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

Function Documentation

◆ addLocalbranchingConstraintAndObjcutoff()

SCIP_RETCODE addLocalbranchingConstraintAndObjcutoff	(	SCIP *	scip,
		SCIP *	subscip,
		SCIP_HEUR *	heur,
		SCIP_VAR **	subvars )

static

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

Parameters

scip	SCIP data structure
subscip	the subproblem created by localbranching
heur	the local branching heuristic
subvars	the subproblem variables

Definition at line 128 of file heur_localbranching.c.

References assert(), cutoff, FALSE, heurdata, i, MIN, NULL, SCIP_CALL, SCIP_MAXSTRLEN, SCIP_OKAY, SCIP_Real, SCIP_VARTYPE_BINARY, SCIPaddCons(), SCIPallocBufferArray, SCIPcreateConsLinear(), SCIPfreeBufferArray, SCIPgetBestSol(), SCIPgetLowerbound(), SCIPgetProbName(), SCIPgetSolVal(), SCIPgetUpperbound(), SCIPgetVarsData(), SCIPheurGetData(), SCIPisFeasEQ(), SCIPisFeasIntegral(), SCIPisInfinity(), SCIPreleaseCons(), SCIPsetObjlimit(), SCIPsnprintf(), SCIPsumepsilon(), SCIPvarGetType(), SCIPvarIsImpliedIntegral(), TRUE, and vars.

Referenced by setupAndSolveSubscipLocalbranching().

◆ SCIP_DECL_EVENTEXEC()

SCIP_DECL_EVENTEXEC ( eventExecLocalbranching )

static

event handler execution callback to interrupt the solution process

Definition at line 238 of file heur_localbranching.c.

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

◆ SCIP_DECL_HEURCOPY()

SCIP_DECL_HEURCOPY ( heurCopyLocalbranching )

static

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

Definition at line 268 of file heur_localbranching.c.

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

◆ SCIP_DECL_HEURFREE()

SCIP_DECL_HEURFREE ( heurFreeLocalbranching )

static

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

Definition at line 282 of file heur_localbranching.c.

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

◆ SCIP_DECL_HEURINIT()

SCIP_DECL_HEURINIT ( heurInitLocalbranching )

static

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

Definition at line 303 of file heur_localbranching.c.

References assert(), heurdata, NULL, SCIP_OKAY, SCIPheurGetData(), and WAITFORNEWSOL.

◆ setupAndSolveSubscipLocalbranching()

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

static

setup And solve local branching 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 327 of file heur_localbranching.c.

References addLocalbranchingConstraintAndObjcutoff(), assert(), EVENTHDLR_DESC, EVENTHDLR_NAME, EXECUTE, FALSE, HEUR_NAME, heurdata, i, MAX, NULL, nvars, result, SCIP_Bool, SCIP_CALL, SCIP_CALL_ABORT, SCIP_DIDNOTRUN, SCIP_EVENTTYPE_LPSOLVED, SCIP_FOUNDSOL, SCIP_Longint, SCIP_LONGINT_FORMAT, SCIP_OKAY, SCIP_PLUGINNOTFOUND, SCIP_STATUS_BESTSOLLIMIT, SCIP_STATUS_DUALLIMIT, SCIP_STATUS_GAPLIMIT, SCIP_STATUS_INFEASIBLE, SCIP_STATUS_INFORUNBD, SCIP_STATUS_MEMLIMIT, SCIP_STATUS_NODELIMIT, SCIP_STATUS_OPTIMAL, SCIP_STATUS_PRIMALLIMIT, SCIP_STATUS_RESTARTLIMIT, SCIP_STATUS_SOLLIMIT, SCIP_STATUS_STALLNODELIMIT, SCIP_STATUS_TERMINATE, SCIP_STATUS_TIMELIMIT, SCIP_STATUS_TOTALNODELIMIT, SCIP_STATUS_UNBOUNDED, SCIP_STATUS_UNKNOWN, SCIP_STATUS_USERINTERRUPT, SCIPallocBufferArray, SCIPblkmem(), SCIPcatchEvent(), SCIPcopyLargeNeighborhoodSearch(), SCIPdebug, SCIPdebugMsg, SCIPdropEvent(), SCIPerrorMessage, SCIPfreeBufferArray, SCIPgetNNodes(), SCIPgetStatus(), SCIPgetVarsData(), SCIPhashmapCreate(), SCIPhashmapFree(), SCIPhashmapGetImage(), SCIPheurGetData(), SCIPincludeEventhdlrBasic(), SCIPprintStatistics(), SCIPsetCommonSubscipParams(), SCIPsolve(), SCIPtransformProb(), SCIPtranslateSubSols(), vars, and WAITFORNEWSOL.

Referenced by SCIP_DECL_HEUREXEC().

◆ SCIP_DECL_HEUREXEC()

SCIP_DECL_HEUREXEC ( heurExecLocalbranching )

static

execution method of primal heuristic

Definition at line 497 of file heur_localbranching.c.

References assert(), EXECUTE, heurdata, MIN, NULL, result, 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.

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

◆ EVENTHDLR_NAME

◆ EVENTHDLR_DESC

◆ EXECUTE

◆ WAITFORNEWSOL

Function Documentation

◆ addLocalbranchingConstraintAndObjcutoff()

◆ SCIP_DECL_EVENTEXEC()

◆ SCIP_DECL_HEURCOPY()

◆ SCIP_DECL_HEURFREE()

◆ SCIP_DECL_HEURINIT()

◆ setupAndSolveSubscipLocalbranching()

◆ SCIP_DECL_HEUREXEC()