heur_rins.c File Reference

Detailed Description

LNS heuristic that combines the incumbent with the LP optimum.

Author

Timo Berthold

Definition in file heur_rins.c.

#include <assert.h>
#include <string.h>
#include "scip/scip.h"
#include "scip/scipdefplugins.h"
#include "scip/cons_linear.h"
#include "scip/heur_rins.h"
#include "scip/pub_misc.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   'N'
#define	HEUR_PRIORITY   -1101000
#define	HEUR_FREQ   25
#define	HEUR_FREQOFS   0
#define	HEUR_MAXDEPTH   -1
#define	HEUR_TIMING   SCIP_HEURTIMING_AFTERLPNODE
#define	HEUR_USESSUBSCIP   TRUE
#define	DEFAULT_NODESOFS   500 /* number of nodes added to the contingent of the total nodes */
#define	DEFAULT_MAXNODES   5000 /* maximum number of nodes to regard in the subproblem */
#define	DEFAULT_MINNODES   50 /* minimum number of nodes to regard in the subproblem */
#define	DEFAULT_MINIMPROVE   0.01 /* factor by which RINS should at least improve the incumbent */
#define	DEFAULT_MINFIXINGRATE   0.3 /* minimum percentage of integer variables that have to be fixed */
#define	DEFAULT_NODESQUOT   0.1 /* subproblem nodes in relation to nodes of the original problem */
#define	DEFAULT_LPLIMFAC   2.0 /* 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	EVENTHDLR_NAME   "Rins"
#define	EVENTHDLR_DESC   "LP event handler for "HEUR_NAME" heuristic"

Functions
static SCIP_RETCODE	createSubproblem (SCIP *scip, SCIP *subscip, SCIP_VAR **subvars, SCIP_Real minfixingrate, SCIP_Bool uselprows, SCIP_Bool *success)
static SCIP_RETCODE	createNewSol (SCIP *scip, SCIP *subscip, SCIP_VAR **subvars, SCIP_HEUR *heur, SCIP_SOL *subsol, SCIP_Bool *success)
static	SCIP_DECL_EVENTEXEC (eventExecRins)
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

#define HEUR_NAME   "rins"

Definition at line 31 of file heur_rins.c.

Referenced by SCIP_DECL_HEURCOPY(), SCIP_DECL_HEUREXEC(), and SCIPincludeHeurRins().

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

Definition at line 32 of file heur_rins.c.

Referenced by SCIPincludeHeurRins().

#define HEUR_DISPCHAR   'N'

Definition at line 33 of file heur_rins.c.

Referenced by SCIPincludeHeurRins().

#define HEUR_PRIORITY   -1101000

Definition at line 34 of file heur_rins.c.

Referenced by SCIPincludeHeurRins().

#define HEUR_FREQ   25

Definition at line 35 of file heur_rins.c.

Referenced by SCIPincludeHeurRins().

#define HEUR_FREQOFS   0

Definition at line 36 of file heur_rins.c.

Referenced by SCIPincludeHeurRins().

#define HEUR_MAXDEPTH   -1

Definition at line 37 of file heur_rins.c.

Referenced by SCIPincludeHeurRins().

#define HEUR_TIMING   SCIP_HEURTIMING_AFTERLPNODE

Definition at line 38 of file heur_rins.c.

Referenced by SCIPincludeHeurRins().

#define HEUR_USESSUBSCIP   TRUE

does the heuristic use a secondary SCIP instance?

Definition at line 39 of file heur_rins.c.

Referenced by SCIPincludeHeurRins().

#define DEFAULT_NODESOFS   500 /* number of nodes added to the contingent of the total nodes */

Definition at line 41 of file heur_rins.c.

Referenced by SCIPincludeHeurRins().

#define DEFAULT_MAXNODES   5000 /* maximum number of nodes to regard in the subproblem */

Definition at line 42 of file heur_rins.c.

Referenced by SCIPincludeHeurRins().

#define DEFAULT_MINNODES   50 /* minimum number of nodes to regard in the subproblem */

Definition at line 43 of file heur_rins.c.

Referenced by SCIPincludeHeurRins().

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

Definition at line 44 of file heur_rins.c.

Referenced by SCIPincludeHeurRins().

#define DEFAULT_MINFIXINGRATE   0.3 /* minimum percentage of integer variables that have to be fixed */

Definition at line 45 of file heur_rins.c.

Referenced by SCIPincludeHeurRins().

#define DEFAULT_NODESQUOT   0.1 /* subproblem nodes in relation to nodes of the original problem */

Definition at line 46 of file heur_rins.c.

Referenced by SCIPincludeHeurRins().

#define DEFAULT_LPLIMFAC   2.0 /* factor by which the limit on the number of LP depends on the node limit */

Definition at line 47 of file heur_rins.c.

Referenced by SCIPincludeHeurRins().

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

Definition at line 48 of file heur_rins.c.

Referenced by SCIPincludeHeurRins().

#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 */

Definition at line 49 of file heur_rins.c.

Referenced by SCIPincludeHeurRins().

#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 50 of file heur_rins.c.

Referenced by SCIPincludeHeurRins().

#define EVENTHDLR_NAME   "Rins"

Definition at line 53 of file heur_rins.c.

Referenced by SCIP_DECL_EVENTEXEC(), and SCIP_DECL_HEUREXEC().

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

Definition at line 54 of file heur_rins.c.

Referenced by SCIP_DECL_HEUREXEC().

Function Documentation

static SCIP_RETCODE createSubproblem ( SCIP *  scip, SCIP *  subscip, SCIP_VAR **  subvars, SCIP_Real  minfixingrate, SCIP_Bool  uselprows, SCIP_Bool *  success  )

static

creates a subproblem for subscip by fixing a number of variables

Parameters

scip	original SCIP data structure
subscip	SCIP data structure for the subproblem
subvars	the variables of the subproblem
minfixingrate	percentage of integer variables that have to be fixed
uselprows	should subproblem be created out of the rows in the LP rows?
success	pointer to store whether the problem was created successfully

Definition at line 85 of file heur_rins.c.

References FALSE, MAX, NULL, SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIPaddCons(), SCIPallocBufferArray, SCIPchgVarLbGlobal(), SCIPchgVarUbGlobal(), SCIPcolGetVar(), SCIPcreateConsLinear(), SCIPfreeBufferArray, SCIPgetBestSol(), SCIPgetLPRowsData(), SCIPgetSolVal(), SCIPgetVarsData(), SCIPisFeasEQ(), SCIPreleaseCons(), SCIProwGetCols(), SCIProwGetConstant(), SCIProwGetLhs(), SCIProwGetName(), SCIProwGetNNonz(), SCIProwGetRhs(), SCIProwGetVals(), SCIProwIsLocal(), SCIPvarGetLPSol(), SCIPvarGetProbindex(), and TRUE.

Referenced by SCIP_DECL_HEUREXEC().

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	RINS heuristic structure
subsol	solution of the subproblem
success	used to store whether new solution was found or not

Definition at line 206 of file heur_rins.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().

static SCIP_DECL_EVENTEXEC ( eventExecRins  )

static

Definition at line 256 of file heur_rins.c.

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

static SCIP_DECL_HEURCOPY ( heurCopyRins  )

static

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

Definition at line 286 of file heur_rins.c.

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

static SCIP_DECL_HEURFREE ( heurFreeRins  )

static

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

Definition at line 300 of file heur_rins.c.

References NULL, SCIP_OKAY, SCIPfreeMemory, SCIPheurGetData(), and SCIPheurSetData().

static SCIP_DECL_HEURINIT ( heurInitRins  )

static

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

Definition at line 321 of file heur_rins.c.

References NULL, SCIP_OKAY, and SCIPheurGetData().

static SCIP_DECL_HEUREXEC ( heurExecRins  )

static

execution method of primal heuristic

Definition at line 341 of file heur_rins.c.

References createNewSol(), createSubproblem(), EVENTHDLR_DESC, EVENTHDLR_NAME, FALSE, HEUR_NAME, MAX, MIN, NULL, SCIP_Bool, SCIP_CALL, SCIP_DELAYED, SCIP_DIDNOTFIND, SCIP_DIDNOTRUN, SCIP_EVENTTYPE_LPSOLVED, SCIP_FOUNDSOL, SCIP_Longint, SCIP_LPSOLSTAT_OPTIMAL, SCIP_MAXSTRLEN, SCIP_OKAY, SCIP_PARAMSETTING_FAST, SCIP_PARAMSETTING_OFF, SCIP_PLUGINNOTFOUND, SCIP_Real, SCIPallocBufferArray, SCIPblkmem(), SCIPcalcHashtableSize(), SCIPcatchEvent(), SCIPcopy(), SCIPcopyCuts(), SCIPcopyVars(), SCIPcreate(), SCIPcreateProb(), SCIPdebug, SCIPdebugMessage, SCIPdropEvent(), SCIPerrorMessage, SCIPfindBranchrule(), SCIPfindConshdlr(), SCIPfindNodesel(), SCIPfree(), SCIPfreeBufferArray, SCIPgetBestSol(), SCIPgetCutoffbound(), SCIPgetLowerbound(), SCIPgetLPObjval(), SCIPgetLPSolstat(), SCIPgetMemExternEstim(), SCIPgetMemUsed(), SCIPgetNNodes(), SCIPgetNSols(), SCIPgetProbName(), SCIPgetRealParam(), SCIPgetSolNodenum(), SCIPgetSols(), SCIPgetSolvingTime(), SCIPgetUpperbound(), SCIPgetVarsData(), SCIPhasCurrentNodeLP(), SCIPhashmapCreate(), SCIPhashmapFree(), SCIPhashmapGetImage(), SCIPheurGetData(), SCIPheurGetNBestSolsFound(), SCIPheurGetNCalls(), SCIPincludeDefaultPlugins(), SCIPincludeEventhdlrBasic(), SCIPinfinity(), SCIPisGE(), SCIPisInfinity(), SCIPisParamFixed(), SCIPisStopped(), SCIPprintStatistics(), SCIPsetBoolParam(), SCIPsetIntParam(), SCIPsetLongintParam(), SCIPsetObjlimit(), SCIPsetPresolving(), SCIPsetRealParam(), SCIPsetSeparating(), SCIPsetSubscipsOff(), SCIPsnprintf(), SCIPsolIsOriginal(), SCIPsolve(), SCIPsumepsilon(), SCIPtransformProb(), SCIPwarningMessage(), and TRUE.

SCIP_RETCODE SCIPincludeHeurRins

(

SCIP *

scip

)

creates the RINS primal heuristic and includes it in SCIP

Parameters

scip	SCIP data structure

Definition at line 671 of file heur_rins.c.

References DEFAULT_COPYCUTS, DEFAULT_LPLIMFAC, DEFAULT_MAXNODES, DEFAULT_MINFIXINGRATE, DEFAULT_MINIMPROVE, DEFAULT_MINNODES, DEFAULT_NODESOFS, DEFAULT_NODESQUOT, DEFAULT_NWAITINGNODES, DEFAULT_USELPROWS, FALSE, HEUR_DESC, HEUR_DISPCHAR, HEUR_FREQ, HEUR_FREQOFS, HEUR_MAXDEPTH, HEUR_NAME, HEUR_PRIORITY, HEUR_TIMING, HEUR_USESSUBSCIP, NULL, SCIP_CALL, SCIP_OKAY, SCIP_REAL_MAX, SCIPaddBoolParam(), SCIPaddIntParam(), SCIPaddRealParam(), SCIPallocMemory, SCIPincludeHeurBasic(), SCIPsetHeurCopy(), SCIPsetHeurFree(), SCIPsetHeurInit(), and TRUE.

Referenced by SCIP_DECL_HEURCOPY(), and SCIPincludeDefaultPlugins().