heur_ofins.c File Reference

Detailed Description

OFINS - Objective Function Induced Neighborhood Search. Primal heuristic for reoptimization.

Author

Jakob Witzig

Definition in file heur_ofins.c.

#include <assert.h>
#include <string.h>
#include <stdio.h>
#include "scip/heur_ofins.h"
#include "scip/scipdefplugins.h"
#include "scip/pub_misc.h"

Go to the source code of this file.

Macros
#define	HEUR_NAME   "ofins"
#define	HEUR_DESC   "primal heuristic for reoptimization, objective function induced neighborhood search"
#define	HEUR_DISPCHAR   'A'
#define	HEUR_PRIORITY   60000
#define	HEUR_FREQ   -1
#define	HEUR_FREQOFS   0
#define	HEUR_MAXDEPTH   0
#define	HEUR_TIMING   SCIP_HEURTIMING_BEFORENODE
#define	HEUR_USESSUBSCIP   TRUE
#define	DEFAULT_MAXNODES   5000LL /* maximum number of nodes to regard in the subproblem */
#define	DEFAULT_MAXCHGRATE   0.50 /* maximum percentage of changed objective coefficients */
#define	DEFAULT_COPYCUTS
#define	DEFAULT_MAXCHANGE   0.04 /* maximal rate of change per coefficient to get fixed */
#define	DEFAULT_MINIMPROVE   0.01 /* factor by which OFINS should at least improve the incumbent */
#define	DEFAULT_ADDALLSOLS   FALSE /* should all subproblem solutions be added to the original SCIP? */
#define	DEFAULT_MINNODES   50LL /* minimum number of nodes to regard in the subproblem */
#define	DEFAULT_NODESOFS   500LL /* number of nodes added to the contingent of the total nodes */
#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	EVENTHDLR_NAME   "Ofins"
#define	EVENTHDLR_DESC   "LP event handler for " HEUR_NAME " heuristic"

Functions
static	SCIP_DECL_EVENTEXEC (eventExecOfins)
static SCIP_RETCODE	createSubproblem (SCIP *scip, SCIP *subscip, SCIP_VAR **subvars, SCIP_Bool *chgcoeffs)
static SCIP_RETCODE	createNewSol (SCIP *scip, SCIP *subscip, SCIP_VAR **subvars, SCIP_HEUR *heur, SCIP_SOL *subsol, SCIP_Bool *success)
static SCIP_RETCODE	applyOfins (SCIP *scip, SCIP_HEUR *heur, SCIP_HEURDATA *heurdata, SCIP_RESULT *result, SCIP_Longint nstallnodes, SCIP_Bool *chgcoeffs)
static	SCIP_DECL_HEURFREE (heurFreeOfins)
static	SCIP_DECL_HEUREXEC (heurExecOfins)
SCIP_RETCODE	SCIPincludeHeurOfins (SCIP *scip)

Macro Definition Documentation

#define HEUR_NAME   "ofins"

Definition at line 31 of file heur_ofins.c.

Referenced by applyOfins(), and SCIPincludeHeurOfins().

#define HEUR_DESC   "primal heuristic for reoptimization, objective function induced neighborhood search"

Definition at line 32 of file heur_ofins.c.

Referenced by SCIPincludeHeurOfins().

#define HEUR_DISPCHAR   'A'

Definition at line 33 of file heur_ofins.c.

Referenced by SCIPincludeHeurOfins().

#define HEUR_PRIORITY   60000

Definition at line 34 of file heur_ofins.c.

Referenced by SCIPincludeHeurOfins().

#define HEUR_FREQ   -1

Definition at line 35 of file heur_ofins.c.

Referenced by SCIPincludeHeurOfins().

#define HEUR_FREQOFS   0

Definition at line 36 of file heur_ofins.c.

Referenced by SCIPincludeHeurOfins().

#define HEUR_MAXDEPTH   0

Definition at line 37 of file heur_ofins.c.

Referenced by SCIPincludeHeurOfins().

#define HEUR_TIMING   SCIP_HEURTIMING_BEFORENODE

Definition at line 38 of file heur_ofins.c.

Referenced by SCIPincludeHeurOfins().

#define HEUR_USESSUBSCIP   TRUE

does the heuristic use a secondary SCIP instance?

Definition at line 39 of file heur_ofins.c.

Referenced by SCIPincludeHeurOfins().

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

Definition at line 42 of file heur_ofins.c.

Referenced by SCIPincludeHeurOfins().

#define DEFAULT_MAXCHGRATE   0.50 /* maximum percentage of changed objective coefficients */

Definition at line 43 of file heur_ofins.c.

Referenced by SCIPincludeHeurOfins().

#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 44 of file heur_ofins.c.

Referenced by SCIPincludeHeurOfins().

#define DEFAULT_MAXCHANGE   0.04 /* maximal rate of change per coefficient to get fixed */

Definition at line 47 of file heur_ofins.c.

Referenced by SCIPincludeHeurOfins().

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

Definition at line 48 of file heur_ofins.c.

Referenced by SCIPincludeHeurOfins().

#define DEFAULT_ADDALLSOLS   FALSE /* should all subproblem solutions be added to the original SCIP? */

Definition at line 49 of file heur_ofins.c.

Referenced by SCIPincludeHeurOfins().

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

Definition at line 50 of file heur_ofins.c.

Referenced by SCIPincludeHeurOfins().

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

Definition at line 51 of file heur_ofins.c.

Referenced by SCIPincludeHeurOfins().

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

Definition at line 52 of file heur_ofins.c.

Referenced by SCIPincludeHeurOfins().

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

Definition at line 53 of file heur_ofins.c.

Referenced by SCIPincludeHeurOfins().

#define EVENTHDLR_NAME   "Ofins"

Definition at line 56 of file heur_ofins.c.

Referenced by applyOfins(), and SCIP_DECL_EVENTEXEC().

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

Definition at line 57 of file heur_ofins.c.

Referenced by applyOfins().

Function Documentation

static SCIP_DECL_EVENTEXEC ( eventExecOfins  )

static

Definition at line 83 of file heur_ofins.c.

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

static SCIP_RETCODE createSubproblem ( SCIP *  scip, SCIP *  subscip, SCIP_VAR **  subvars, SCIP_Bool *  chgcoeffs  )

static

creates a subproblem 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
chgcoeffs	array indicating which coefficients have changed

Definition at line 108 of file heur_ofins.c.

References NULL, SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIPchgVarLbGlobal(), SCIPchgVarUbGlobal(), SCIPdebugMessage, SCIPgetNBinVars(), SCIPgetReoptLastOptSol(), SCIPgetSolVal(), SCIPgetUpperbound(), SCIPgetVars(), and SCIPsetObjlimit().

Referenced by applyOfins().

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

Definition at line 158 of file heur_ofins.c.

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

Referenced by applyOfins().

static SCIP_RETCODE applyOfins ( SCIP *  scip, SCIP_HEUR *  heur, SCIP_HEURDATA *  heurdata, SCIP_RESULT *  result, SCIP_Longint  nstallnodes, SCIP_Bool *  chgcoeffs  )

static

main procedure of the OFINS heuristic, creates and solves a sub-SCIP

Parameters

scip	original SCIP data structure
heur	heuristic data structure
heurdata	euristic's private data structure
result	result data structure
nstallnodes	number of stalling nodes for the subproblem
chgcoeffs	array of changed coefficients

Definition at line 204 of file heur_ofins.c.

References createNewSol(), createSubproblem(), EVENTHDLR_DESC, EVENTHDLR_NAME, FALSE, HEUR_NAME, NULL, SCIP_Bool, SCIP_CALL, SCIP_DIDNOTFIND, SCIP_DIDNOTRUN, SCIP_EVENTTYPE_LPSOLVED, SCIP_FOUNDSOL, SCIP_OKAY, SCIP_PARAMSETTING_FAST, SCIP_PARAMSETTING_OFF, SCIP_PLUGINNOTFOUND, SCIP_Real, SCIPallocBufferArray, SCIPblkmem(), SCIPcalcHashtableSize(), SCIPcatchEvent(), SCIPcopy(), SCIPcopyCuts(), SCIPcreate(), SCIPdebug, SCIPdebugMessage, SCIPdropEvent(), SCIPerrorMessage, SCIPfindBranchrule(), SCIPfindNodesel(), SCIPfree(), SCIPfreeBufferArray, SCIPgetBestSol(), SCIPgetMemExternEstim(), SCIPgetMemUsed(), SCIPgetNConss(), SCIPgetNNodes(), SCIPgetNSols(), SCIPgetNVars(), SCIPgetPrimalbound(), SCIPgetRealParam(), SCIPgetSols(), SCIPgetSolvingTime(), SCIPgetVars(), SCIPhashmapCreate(), SCIPhashmapFree(), SCIPhashmapGetImage(), SCIPincludeEventhdlrBasic(), SCIPinfinity(), SCIPisInfinity(), SCIPisParamFixed(), SCIPpresolve(), SCIPprintStatistics(), SCIPsetBoolParam(), SCIPsetIntParam(), SCIPsetLongintParam(), SCIPsetPresolving(), SCIPsetRealParam(), SCIPsetSeparating(), SCIPsetSubscipsOff(), SCIPsolGetNodenum(), SCIPsolve(), SCIPstatisticPrintf, SCIPtransformProb(), SCIPwarningMessage(), and TRUE.

Referenced by SCIP_DECL_HEUREXEC().

static SCIP_DECL_HEURFREE ( heurFreeOfins  )

static

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

Definition at line 437 of file heur_ofins.c.

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

static SCIP_DECL_HEUREXEC ( heurExecOfins  )

static

execution method of primal heuristic

Definition at line 457 of file heur_ofins.c.

References applyOfins(), FALSE, MAX, MIN, NULL, SCIP_Bool, SCIP_CALL, SCIP_DELAYED, SCIP_DIDNOTRUN, SCIP_INVALID, SCIP_Longint, SCIP_OKAY, SCIP_Real, SCIP_VARSTATUS_ORIGINAL, SCIPallocBufferArray, SCIPdebugMessage, SCIPfreeBufferArray, SCIPgetNBinVars(), SCIPgetNNodes(), SCIPgetNReoptRuns(), SCIPgetReoptOldObjCoef(), SCIPgetVars(), SCIPheurGetData(), SCIPheurGetNBestSolsFound(), SCIPheurGetNCalls(), SCIPisNegative(), SCIPisPositive(), SCIPisReoptEnabled(), SCIPisStopped(), SCIPisZero(), SCIPvarGetObj(), SCIPvarGetOrigvarSum(), SCIPvarGetStatus(), SCIPvarIsActive(), and TRUE.

SCIP_RETCODE SCIPincludeHeurOfins

(

SCIP *

scip

)

creates the ofins primal heuristic and includes it in SCIP

Parameters

scip	SCIP data structure

Definition at line 612 of file heur_ofins.c.

References DEFAULT_ADDALLSOLS, DEFAULT_COPYCUTS, DEFAULT_LPLIMFAC, DEFAULT_MAXCHANGE, DEFAULT_MAXCHGRATE, DEFAULT_MAXNODES, DEFAULT_MINIMPROVE, DEFAULT_MINNODES, DEFAULT_NODESOFS, DEFAULT_NODESQUOT, FALSE, HEUR_DESC, HEUR_DISPCHAR, HEUR_FREQ, HEUR_FREQOFS, HEUR_MAXDEPTH, HEUR_NAME, HEUR_PRIORITY, HEUR_TIMING, HEUR_USESSUBSCIP, NULL, SCIP_CALL, SCIP_LONGINT_MAX, SCIP_OKAY, SCIP_REAL_MAX, SCIPaddBoolParam(), SCIPaddLongintParam(), SCIPaddRealParam(), SCIPallocMemory, SCIPincludeHeurBasic(), SCIPsetHeurFree(), and TRUE.

Referenced by SCIPincludeDefaultPlugins().