heur_dins.c File Reference

Detailed Description

DINS primal heuristic (according to Ghosh)

Author

Timo Berthold

Robert Waniek

Definition in file heur_dins.c.

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

Go to the source code of this file.

Macros
#define	HEUR_NAME   "dins"
#define	HEUR_DESC   "distance induced neighborhood search by Ghosh"
#define	HEUR_DISPCHAR   'D'
#define	HEUR_PRIORITY   -1105000
#define	HEUR_FREQ   -1
#define	HEUR_FREQOFS   0
#define	HEUR_MAXDEPTH   -1
#define	HEUR_TIMING   SCIP_HEURTIMING_AFTERLPNODE
#define	HEUR_USESSUBSCIP   TRUE
#define	DEFAULT_NODESOFS   5000LL /* number of nodes added to the contingent of the total nodes */
#define	DEFAULT_MAXNODES   5000LL /* maximum number of nodes to regard in the subproblem */
#define	DEFAULT_MINNODES   50LL /* minimum number of nodes to regard in the subproblem */
#define	DEFAULT_MINIMPROVE   0.01 /* factor by which DINS should at least improve the incumbent */
#define	DEFAULT_NODESQUOT   0.05 /* subproblem nodes in relation to nodes of the original problem */
#define	DEFAULT_LPLIMFAC   1.5 /* factor by which the limit on the number of LP depends on the node limit */
#define	DEFAULT_MINFIXINGRATE   0.3 /* minimum percentage of integer variables that have to be fixed */
#define	DEFAULT_NWAITINGNODES   0LL /* number of nodes without incumbent change that heuristic should wait */
#define	DEFAULT_NEIGHBORHOODSIZE   18 /* radius of the incumbents neighborhood to be searched */
#define	DEFAULT_SOLNUM   5 /* number of pool-solutions to be checked for flag array update */
#define	DEFAULT_USELPROWS
#define	DEFAULT_COPYCUTS
#define	EVENTHDLR_NAME   "Dins"
#define	EVENTHDLR_DESC   "LP event handler for "HEUR_NAME" heuristic"

Functions
static SCIP_RETCODE	createSubproblem (SCIP *scip, SCIP *subscip, SCIP_VAR **vars, SCIP_VAR **subvars, int nbinvars, int nintvars, int *fixingcounter, SCIP_Bool uselprows)
static SCIP_RETCODE	addLocalBranchingConstraint (SCIP *scip, SCIP *subscip, SCIP_VAR **subvars, SCIP_HEURDATA *heurdata, SCIP_Bool *fixed)
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 (heurCopyDins)
static	SCIP_DECL_HEURFREE (heurFreeDins)
static	SCIP_DECL_HEURINITSOL (heurInitsolDins)
static	SCIP_DECL_HEUREXITSOL (heurExitsolDins)
static	SCIP_DECL_HEUREXEC (heurExecDins)
SCIP_RETCODE	SCIPincludeHeurDins (SCIP *scip)

Macro Definition Documentation

#define HEUR_NAME   "dins"

Definition at line 31 of file heur_dins.c.

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

#define HEUR_DESC   "distance induced neighborhood search by Ghosh"

Definition at line 32 of file heur_dins.c.

Referenced by SCIPincludeHeurDins().

#define HEUR_DISPCHAR   'D'

Definition at line 33 of file heur_dins.c.

Referenced by SCIPincludeHeurDins().

#define HEUR_PRIORITY   -1105000

Definition at line 34 of file heur_dins.c.

Referenced by SCIPincludeHeurDins().

#define HEUR_FREQ   -1

Definition at line 35 of file heur_dins.c.

Referenced by SCIPincludeHeurDins().

#define HEUR_FREQOFS   0

Definition at line 36 of file heur_dins.c.

Referenced by SCIPincludeHeurDins().

#define HEUR_MAXDEPTH   -1

Definition at line 37 of file heur_dins.c.

Referenced by SCIPincludeHeurDins().

#define HEUR_TIMING   SCIP_HEURTIMING_AFTERLPNODE

Definition at line 38 of file heur_dins.c.

Referenced by SCIPincludeHeurDins().

#define HEUR_USESSUBSCIP   TRUE

does the heuristic use a secondary SCIP instance?

Definition at line 39 of file heur_dins.c.

Referenced by SCIPincludeHeurDins().

#define DEFAULT_NODESOFS   5000LL /* number of nodes added to the contingent of the total nodes */

Definition at line 41 of file heur_dins.c.

Referenced by SCIPincludeHeurDins().

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

Definition at line 42 of file heur_dins.c.

Referenced by SCIPincludeHeurDins().

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

Definition at line 43 of file heur_dins.c.

Referenced by SCIPincludeHeurDins().

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

Definition at line 44 of file heur_dins.c.

Referenced by SCIPincludeHeurDins().

#define DEFAULT_NODESQUOT   0.05 /* subproblem nodes in relation to nodes of the original problem */

Definition at line 45 of file heur_dins.c.

Referenced by SCIPincludeHeurDins().

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

Definition at line 46 of file heur_dins.c.

Referenced by SCIPincludeHeurDins().

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

Definition at line 47 of file heur_dins.c.

Referenced by SCIPincludeHeurDins().

#define DEFAULT_NWAITINGNODES   0LL /* number of nodes without incumbent change that heuristic should wait */

Definition at line 48 of file heur_dins.c.

Referenced by SCIPincludeHeurDins().

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

Definition at line 49 of file heur_dins.c.

Referenced by SCIPincludeHeurDins().

#define DEFAULT_SOLNUM   5 /* number of pool-solutions to be checked for flag array update */

Definition at line 50 of file heur_dins.c.

Referenced by SCIPincludeHeurDins().

#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 51 of file heur_dins.c.

Referenced by SCIPincludeHeurDins().

#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_dins.c.

Referenced by SCIPincludeHeurDins().

#define EVENTHDLR_NAME   "Dins"

Definition at line 55 of file heur_dins.c.

Referenced by SCIP_DECL_EVENTEXEC(), and SCIP_DECL_HEUREXEC().

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

Definition at line 56 of file heur_dins.c.

Referenced by SCIP_DECL_HEUREXEC().

Function Documentation

static SCIP_RETCODE createSubproblem ( SCIP *  scip, SCIP *  subscip, SCIP_VAR **  vars, SCIP_VAR **  subvars, int  nbinvars, int  nintvars, int *  fixingcounter, SCIP_Bool  uselprows  )

static

creates a subproblem for subscip by fixing a number of variables

Parameters

scip	SCIP data structure of the original problem
subscip	SCIP data structure of the subproblem
vars	variables of the original problem
subvars	variables of the subproblem
nbinvars	number of binary variables of problem and subproblem
nintvars	number of general integer variables of problem and subproblem
fixingcounter	number of integer variables that get fixed
uselprows	should subproblem be created out of the rows in the LP rows?

Definition at line 93 of file heur_dins.c.

References FALSE, MAX, MIN, NULL, REALABS, SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIP_VARTYPE_INTEGER, SCIPaddCons(), SCIPallocBufferArray, SCIPchgVarLbGlobal(), SCIPchgVarUbGlobal(), SCIPcolGetVar(), SCIPcreateConsLinear(), SCIPfeasCeil(), SCIPfeasFloor(), SCIPfreeBufferArray, SCIPgetBestSol(), SCIPgetLPRowsData(), SCIPgetSolVal(), SCIPisFeasEQ(), SCIPreleaseCons(), SCIProwGetCols(), SCIProwGetConstant(), SCIProwGetLhs(), SCIProwGetName(), SCIProwGetNNonz(), SCIProwGetRhs(), SCIProwGetVals(), SCIProwIsLocal(), SCIPvarGetLbGlobal(), SCIPvarGetLPSol(), SCIPvarGetProbindex(), SCIPvarGetType(), SCIPvarGetUbGlobal(), and TRUE.

Referenced by SCIP_DECL_HEUREXEC().

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

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
fixed	TRUE –> include variable in LB constraint

Definition at line 252 of file heur_dins.c.

References FALSE, NULL, 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 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	DINS heuristic structure
subsol	solution of the subproblem
success	used to store whether new solution was found or not

Definition at line 330 of file heur_dins.c.

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

Referenced by SCIP_DECL_HEUREXEC().

static SCIP_DECL_EVENTEXEC ( eventExecRins  )

static

Definition at line 385 of file heur_dins.c.

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

static SCIP_DECL_HEURCOPY ( heurCopyDins  )

static

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

Definition at line 415 of file heur_dins.c.

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

static SCIP_DECL_HEURFREE ( heurFreeDins  )

static

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

Definition at line 429 of file heur_dins.c.

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

static SCIP_DECL_HEURINITSOL ( heurInitsolDins  )

static

solving process initialization method of primal heuristic (called when branch and bound process is about to begin)

Definition at line 450 of file heur_dins.c.

References NULL, SCIP_CALL, SCIP_OKAY, SCIPallocBlockMemoryArray, SCIPgetNBinVars(), SCIPheurGetData(), and TRUE.

static SCIP_DECL_HEUREXITSOL ( heurExitsolDins  )

static

solving process deinitialization method of primal heuristic (called before branch and bound process data is freed)

Definition at line 481 of file heur_dins.c.

References NULL, SCIP_OKAY, SCIPfreeBlockMemoryArray, and SCIPheurGetData().

static SCIP_DECL_HEUREXEC ( heurExecDins  )

static

execution method of primal heuristic

Definition at line 502 of file heur_dins.c.

References addLocalBranchingConstraint(), 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(), SCIPcalcMemGrowSize(), SCIPcatchEvent(), SCIPcopy(), SCIPcopyCuts(), SCIPcopyVars(), SCIPcreate(), SCIPcreateProb(), SCIPdebug, SCIPdebugMessage, SCIPdropEvent(), SCIPerrorMessage, SCIPfindBranchrule(), SCIPfindConshdlr(), SCIPfindNodesel(), SCIPfixVar(), SCIPfree(), SCIPfreeBufferArray, SCIPgetBestSol(), SCIPgetCutoffbound(), SCIPgetLowerbound(), SCIPgetLPObjval(), SCIPgetLPSolstat(), SCIPgetMemExternEstim(), SCIPgetMemUsed(), SCIPgetNBinVars(), SCIPgetNConss(), SCIPgetNIntVars(), SCIPgetNNodes(), SCIPgetNSols(), SCIPgetNSolsFound(), SCIPgetNVars(), SCIPgetProbName(), SCIPgetRealParam(), SCIPgetSolHeur(), SCIPgetSolNodenum(), SCIPgetSols(), SCIPgetSolVal(), SCIPgetSolvingTime(), SCIPgetUpperbound(), SCIPgetVarsData(), SCIPhasCurrentNodeLP(), SCIPhashmapCreate(), SCIPhashmapFree(), SCIPhashmapGetImage(), SCIPheurGetData(), SCIPheurGetNBestSolsFound(), SCIPheurGetNCalls(), SCIPincludeDefaultPlugins(), SCIPincludeEventhdlrBasic(), SCIPinfinity(), SCIPisFeasEQ(), SCIPisGE(), SCIPisInfinity(), SCIPisParamFixed(), SCIPisStopped(), SCIPprintStatistics(), SCIPreallocBlockMemoryArray, SCIPsetBoolParam(), SCIPsetIntParam(), SCIPsetLongintParam(), SCIPsetObjlimit(), SCIPsetPresolving(), SCIPsetRealParam(), SCIPsetSeparating(), SCIPsetSubscipsOff(), SCIPsnprintf(), SCIPsolve(), SCIPsumepsilon(), SCIPtransformProb(), SCIPvarGetLbGlobal(), SCIPvarGetLPSol(), SCIPvarGetRootSol(), SCIPvarGetUbGlobal(), SCIPwarningMessage(), and TRUE.

SCIP_RETCODE SCIPincludeHeurDins

(

SCIP *

scip

)

creates the DINS primal heuristic and includes it in SCIP

Parameters

scip	SCIP data structure

Definition at line 961 of file heur_dins.c.

References DEFAULT_COPYCUTS, DEFAULT_LPLIMFAC, DEFAULT_MAXNODES, DEFAULT_MINFIXINGRATE, DEFAULT_MINIMPROVE, DEFAULT_MINNODES, DEFAULT_NEIGHBORHOODSIZE, DEFAULT_NODESOFS, DEFAULT_NODESQUOT, DEFAULT_NWAITINGNODES, DEFAULT_SOLNUM, 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_LONGINT_MAX, SCIP_OKAY, SCIP_REAL_MAX, SCIPaddBoolParam(), SCIPaddIntParam(), SCIPaddLongintParam(), SCIPaddRealParam(), SCIPallocMemory, SCIPincludeHeurBasic(), SCIPsetHeurCopy(), SCIPsetHeurExitsol(), SCIPsetHeurFree(), SCIPsetHeurInitsol(), and TRUE.

Referenced by SCIP_DECL_HEURCOPY(), and SCIPincludeDefaultPlugins().