Detailed Description

LNS heuristic that combines the incumbent with the LP optimum.

Author: Timo Berthold

Definition in file heur_rins.c.

#include "blockmemshell/memory.h"
#include "scip/heuristics.h"
#include "scip/heur_rins.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_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"

Go to the source code of this file.

Macros
#define	HEUR_NAME "rins"
#define	HEUR_DESC "relaxation induced neighborhood search by Danna, Rothberg, and Le Pape"
#define	HEUR_DISPCHAR SCIP_HEURDISPCHAR_LNS
#define	HEUR_PRIORITY -1101000
#define	HEUR_FREQ 15
#define	HEUR_FREQOFS 0
#define	HEUR_MAXDEPTH -1
#define	HEUR_TIMING SCIP_HEURTIMING_AFTERLPNODE
#define	HEUR_USESSUBSCIP TRUE
#define	DEFAULT_NODESOFS 500
#define	DEFAULT_MAXNODES 5000
#define	DEFAULT_MINNODES 50
#define	DEFAULT_MINIMPROVE 0.01
#define	DEFAULT_MINFIXINGRATE 0.3
#define	DEFAULT_NODESQUOT 0.3
#define	DEFAULT_LPLIMFAC 2.0
#define	DEFAULT_NWAITINGNODES 200
#define	DEFAULT_USELPROWS FALSE
#define	DEFAULT_COPYCUTS TRUE
#define	DEFAULT_USEUCT FALSE
#define	EVENTHDLR_NAME "Rins"
#define	EVENTHDLR_DESC "LP event handler for " HEUR_NAME " heuristic"

Functions
static SCIP_RETCODE	determineFixings (SCIP scip, SCIP_VAR fixedvars, SCIP_Real fixedvals, int nfixedvars, int fixedvarssize, SCIP_Real minfixingrate, SCIP_Bool success)
static	SCIP_DECL_EVENTEXEC (eventExecRins)
static SCIP_RETCODE	wrapperRins (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 nfixedvars, SCIP_Longint nnodes)
static	SCIP_DECL_HEURCOPY (heurCopyRins)
static	SCIP_DECL_HEURFREE (heurFreeRins)
static	SCIP_DECL_HEURINIT (heurInitRins)
static	SCIP_DECL_HEUREXEC (heurExecRins)
SCIP_RETCODE	SCIPincludeHeurRins (SCIP *scip)

Macro Definition Documentation

◆ HEUR_NAME

#define HEUR_NAME "rins"

Definition at line 60 of file heur_rins.c.

◆ HEUR_DESC

#define HEUR_DESC "relaxation induced neighborhood search by Danna, Rothberg, and Le Pape"

Definition at line 61 of file heur_rins.c.

◆ HEUR_DISPCHAR

#define HEUR_DISPCHAR SCIP_HEURDISPCHAR_LNS

Definition at line 62 of file heur_rins.c.

◆ HEUR_PRIORITY

#define HEUR_PRIORITY -1101000

Definition at line 63 of file heur_rins.c.

◆ HEUR_FREQ

#define HEUR_FREQ 15

Definition at line 64 of file heur_rins.c.

◆ HEUR_FREQOFS

#define HEUR_FREQOFS 0

Definition at line 65 of file heur_rins.c.

◆ HEUR_MAXDEPTH

#define HEUR_MAXDEPTH -1

Definition at line 66 of file heur_rins.c.

◆ HEUR_TIMING

#define HEUR_TIMING SCIP_HEURTIMING_AFTERLPNODE

Definition at line 67 of file heur_rins.c.

◆ HEUR_USESSUBSCIP

#define HEUR_USESSUBSCIP TRUE

does the heuristic use a secondary SCIP instance?

Definition at line 68 of file heur_rins.c.

◆ DEFAULT_NODESOFS

#define DEFAULT_NODESOFS 500

Definition at line 70 of file heur_rins.c.

◆ DEFAULT_MAXNODES

#define DEFAULT_MAXNODES 5000

Definition at line 71 of file heur_rins.c.

◆ DEFAULT_MINNODES

#define DEFAULT_MINNODES 50

Definition at line 72 of file heur_rins.c.

◆ DEFAULT_MINIMPROVE

#define DEFAULT_MINIMPROVE 0.01

Definition at line 73 of file heur_rins.c.

◆ DEFAULT_MINFIXINGRATE

#define DEFAULT_MINFIXINGRATE 0.3

Definition at line 74 of file heur_rins.c.

◆ DEFAULT_NODESQUOT

#define DEFAULT_NODESQUOT 0.3

Definition at line 75 of file heur_rins.c.

◆ DEFAULT_LPLIMFAC

#define DEFAULT_LPLIMFAC 2.0

Definition at line 76 of file heur_rins.c.

◆ DEFAULT_NWAITINGNODES

#define DEFAULT_NWAITINGNODES 200

Definition at line 77 of file heur_rins.c.

◆ DEFAULT_USELPROWS

#define DEFAULT_USELPROWS FALSE

Definition at line 78 of file heur_rins.c.

◆ DEFAULT_COPYCUTS

#define DEFAULT_COPYCUTS TRUE

Definition at line 80 of file heur_rins.c.

◆ DEFAULT_USEUCT

#define DEFAULT_USEUCT FALSE

Definition at line 83 of file heur_rins.c.

◆ EVENTHDLR_NAME

#define EVENTHDLR_NAME "Rins"

Definition at line 86 of file heur_rins.c.

◆ EVENTHDLR_DESC

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

Definition at line 87 of file heur_rins.c.

Function Documentation

◆ determineFixings()

SCIP_RETCODE determineFixings	(	SCIP *	scip,
		SCIP_VAR **	fixedvars,
		SCIP_Real *	fixedvals,
		int *	nfixedvars,
		int	fixedvarssize,
		SCIP_Real	minfixingrate,
		SCIP_Bool *	success )

static

determines variable fixings for RINS

RINS fixes variables with matching solution values in the current LP and the incumbent solution

Parameters

scip	original SCIP data structure
fixedvars	array to store source SCIP variables that should be fixed in the copy
fixedvals	array to store fixing values for variables that should be fixed in the copy
nfixedvars	pointer to store the number of variables that RINS can fix
fixedvarssize	size of the buffer arrays to store potential fixings
minfixingrate	percentage of integer variables that have to be fixed
success	pointer to store whether sufficiently many variable fixings were found

Definition at line 126 of file heur_rins.c.

References assert(), determineFixings(), FALSE, i, MAX, NULL, nvars, SCIP_Bool, SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIPgetBestSol(), SCIPgetSolVal(), SCIPgetVarsData(), SCIPisFeasEQ(), SCIPvarGetLPSol(), TRUE, and vars.

Referenced by determineFixings(), and SCIP_DECL_HEUREXEC().

◆ SCIP_DECL_EVENTEXEC()

SCIP_DECL_EVENTEXEC ( eventExecRins )

static

Definition at line 374 of file heur_rins.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().

◆ wrapperRins()

SCIP_RETCODE wrapperRins	(	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	nfixedvars,
		SCIP_Longint	nnodes )

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
nfixedvars	Number of fixed variables
nnodes	Number of nodes in the b&b tree

Definition at line 206 of file heur_rins.c.

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

Referenced by SCIP_DECL_HEUREXEC(), and wrapperRins().

◆ SCIP_DECL_HEURCOPY()

SCIP_DECL_HEURCOPY ( heurCopyRins )

static

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

Definition at line 405 of file heur_rins.c.

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

◆ SCIP_DECL_HEURFREE()

SCIP_DECL_HEURFREE ( heurFreeRins )

static

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

Definition at line 420 of file heur_rins.c.

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

◆ SCIP_DECL_HEURINIT()

SCIP_DECL_HEURINIT ( heurInitRins )

static

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

Definition at line 441 of file heur_rins.c.

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

◆ SCIP_DECL_HEUREXEC()

SCIP_DECL_HEUREXEC ( heurExecRins )

static

execution method of primal heuristic

Definition at line 461 of file heur_rins.c.

References assert(), determineFixings(), FALSE, heurdata, MIN, nnodes, 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(), SCIPdebugMsg, SCIPfree(), SCIPfreeBufferArray, SCIPgetBestSol(), SCIPgetCutoffbound(), SCIPgetLPObjval(), SCIPgetLPSolstat(), SCIPgetNNodes(), SCIPgetNSols(), SCIPgetSolNodenum(), SCIPgetVarsData(), SCIPhasCurrentNodeLP(), SCIPheurGetData(), SCIPheurGetNBestSolsFound(), SCIPheurGetNCalls(), SCIPisGE(), SCIPisStopped(), SCIPsolIsOriginal(), vars, and wrapperRins().

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_MINFIXINGRATE

◆ DEFAULT_NODESQUOT

◆ DEFAULT_LPLIMFAC

◆ DEFAULT_NWAITINGNODES

◆ DEFAULT_USELPROWS

◆ DEFAULT_COPYCUTS

◆ DEFAULT_USEUCT

◆ EVENTHDLR_NAME

◆ EVENTHDLR_DESC

Function Documentation

◆ determineFixings()

◆ SCIP_DECL_EVENTEXEC()

◆ wrapperRins()

◆ SCIP_DECL_HEURCOPY()

◆ SCIP_DECL_HEURFREE()

◆ SCIP_DECL_HEURINIT()

◆ SCIP_DECL_HEUREXEC()