heur_crossover.c File Reference

Detailed Description

crossover primal heuristic

Author

Timo Berthold

Definition in file heur_crossover.c.

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

Go to the source code of this file.

Macros
#define	HEUR_NAME   "crossover"
#define	HEUR_DESC   "LNS heuristic that fixes all variables that are identic in a couple of solutions"
#define	HEUR_DISPCHAR   'C'
#define	HEUR_PRIORITY   -1104000
#define	HEUR_FREQ   30
#define	HEUR_FREQOFS   0
#define	HEUR_MAXDEPTH   -1
#define	HEUR_TIMING   SCIP_HEURTIMING_AFTERNODE
#define	HEUR_USESSUBSCIP   TRUE
#define	DEFAULT_MAXNODES   5000LL /* maximum number of nodes to regard in the subproblem */
#define	DEFAULT_MINIMPROVE   0.01 /* factor by which Crossover should at least improve the incumbent */
#define	DEFAULT_MINNODES   50LL /* minimum number of nodes to regard in the subproblem */
#define	DEFAULT_MINFIXINGRATE   0.666 /* minimum percentage of integer variables that have to be fixed */
#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	DEFAULT_NUSEDSOLS   3 /* number of solutions that will be taken into account */
#define	DEFAULT_NWAITINGNODES   200LL /* number of nodes without incumbent change heuristic should wait */
#define	DEFAULT_RANDOMIZATION   TRUE /* should the choice which sols to take be randomized? */
#define	DEFAULT_DONTWAITATROOT   FALSE /* should the nwaitingnodes parameter be ignored at the root node? */
#define	DEFAULT_USELPROWS
#define	DEFAULT_COPYCUTS
#define	DEFAULT_PERMUTE   FALSE /* should the subproblem be permuted to increase diversification? */
#define	HASHSIZE_SOLS   11113 /* size of hash table for solution tuples in crossover heuristic */
#define	EVENTHDLR_NAME   "Crossover"
#define	EVENTHDLR_DESC   "LP event handler for "HEUR_NAME" heuristic"

Typedefs
typedef struct SolTuple	SOLTUPLE

Functions
static	SCIP_DECL_HASHGETKEY (hashGetKeySols)
static	SCIP_DECL_HASHKEYEQ (hashKeyEqSols)
static	SCIP_DECL_HASHKEYVAL (hashKeyValSols)
static unsigned int	calculateHashKey (int *indices, int size)
static void	sortArray (int *a, int size)
static SCIP_RETCODE	createSolTuple (SCIP *scip, SOLTUPLE **elem, int *indices, int size, SCIP_HEURDATA *heurdata)
static SCIP_Bool	solHasNewSource (SCIP_SOL **sols, int *selection, int selectionsize, int newsol)
static SCIP_RETCODE	selectSolsRandomized (SCIP *scip, int *selection, SCIP_HEURDATA *heurdata, SCIP_Bool *success)
static SCIP_RETCODE	fixVariables (SCIP *scip, SCIP *subscip, SCIP_VAR **subvars, int *selection, SCIP_HEURDATA *heurdata, SCIP_Bool *success)
static SCIP_RETCODE	createRows (SCIP *scip, SCIP *subscip, SCIP_VAR **subvars)
static SCIP_RETCODE	setupSubproblem (SCIP *scip, SCIP *subscip, SCIP_VAR **subvars, int *selection, SCIP_HEURDATA *heurdata, SCIP_Bool *success)
static SCIP_RETCODE	createNewSol (SCIP *scip, SCIP *subscip, SCIP_VAR **subvars, SCIP_HEUR *heur, SCIP_SOL *subsol, int *solindex, SCIP_Bool *success)
static void	updateFailureStatistic (SCIP *scip, SCIP_HEURDATA *heurdata)
static	SCIP_DECL_EVENTEXEC (eventExecCrossover)
static	SCIP_DECL_HEURCOPY (heurCopyCrossover)
static	SCIP_DECL_HEURFREE (heurFreeCrossover)
static	SCIP_DECL_HEURINIT (heurInitCrossover)
static	SCIP_DECL_HEUREXIT (heurExitCrossover)
static	SCIP_DECL_HEUREXEC (heurExecCrossover)
SCIP_RETCODE	SCIPincludeHeurCrossover (SCIP *scip)

Macro Definition Documentation

#define HEUR_NAME   "crossover"

Definition at line 32 of file heur_crossover.c.

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

#define HEUR_DESC   "LNS heuristic that fixes all variables that are identic in a couple of solutions"

Definition at line 33 of file heur_crossover.c.

Referenced by SCIPincludeHeurCrossover().

#define HEUR_DISPCHAR   'C'

Definition at line 34 of file heur_crossover.c.

Referenced by SCIPincludeHeurCrossover().

#define HEUR_PRIORITY   -1104000

Definition at line 35 of file heur_crossover.c.

Referenced by SCIPincludeHeurCrossover().

#define HEUR_FREQ   30

Definition at line 36 of file heur_crossover.c.

Referenced by SCIPincludeHeurCrossover().

#define HEUR_FREQOFS   0

Definition at line 37 of file heur_crossover.c.

Referenced by SCIPincludeHeurCrossover().

#define HEUR_MAXDEPTH   -1

Definition at line 38 of file heur_crossover.c.

Referenced by SCIPincludeHeurCrossover().

#define HEUR_TIMING   SCIP_HEURTIMING_AFTERNODE

Definition at line 39 of file heur_crossover.c.

Referenced by SCIPincludeHeurCrossover().

#define HEUR_USESSUBSCIP   TRUE

does the heuristic use a secondary SCIP instance?

Definition at line 40 of file heur_crossover.c.

Referenced by SCIPincludeHeurCrossover().

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

Definition at line 42 of file heur_crossover.c.

Referenced by SCIPincludeHeurCrossover().

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

Definition at line 43 of file heur_crossover.c.

Referenced by SCIPincludeHeurCrossover().

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

Definition at line 44 of file heur_crossover.c.

Referenced by SCIPincludeHeurCrossover().

#define DEFAULT_MINFIXINGRATE   0.666 /* minimum percentage of integer variables that have to be fixed */

Definition at line 45 of file heur_crossover.c.

Referenced by SCIPincludeHeurCrossover().

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

Definition at line 46 of file heur_crossover.c.

Referenced by SCIPincludeHeurCrossover().

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

Definition at line 47 of file heur_crossover.c.

Referenced by SCIPincludeHeurCrossover().

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

Definition at line 48 of file heur_crossover.c.

Referenced by SCIPincludeHeurCrossover().

#define DEFAULT_NUSEDSOLS   3 /* number of solutions that will be taken into account */

Definition at line 49 of file heur_crossover.c.

Referenced by SCIPincludeHeurCrossover().

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

Definition at line 50 of file heur_crossover.c.

Referenced by SCIPincludeHeurCrossover().

#define DEFAULT_RANDOMIZATION   TRUE /* should the choice which sols to take be randomized? */

Definition at line 51 of file heur_crossover.c.

Referenced by SCIPincludeHeurCrossover().

#define DEFAULT_DONTWAITATROOT   FALSE /* should the nwaitingnodes parameter be ignored at the root node? */

Definition at line 52 of file heur_crossover.c.

Referenced by SCIPincludeHeurCrossover().

#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 53 of file heur_crossover.c.

Referenced by SCIPincludeHeurCrossover().

#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 54 of file heur_crossover.c.

Referenced by SCIPincludeHeurCrossover().

#define DEFAULT_PERMUTE   FALSE /* should the subproblem be permuted to increase diversification? */

Definition at line 55 of file heur_crossover.c.

Referenced by SCIPincludeHeurCrossover().

#define HASHSIZE_SOLS   11113 /* size of hash table for solution tuples in crossover heuristic */

Definition at line 56 of file heur_crossover.c.

Referenced by SCIP_DECL_HEURINIT().

#define EVENTHDLR_NAME   "Crossover"

Definition at line 59 of file heur_crossover.c.

Referenced by SCIP_DECL_EVENTEXEC(), and SCIP_DECL_HEUREXEC().

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

Definition at line 60 of file heur_crossover.c.

Referenced by SCIP_DECL_HEUREXEC().

Typedef Documentation

typedef struct SolTuple SOLTUPLE

Definition at line 66 of file heur_crossover.c.

Function Documentation

static SCIP_DECL_HASHGETKEY ( hashGetKeySols  )

static

gets the hash key of a solution tuple

Definition at line 117 of file heur_crossover.c.

static SCIP_DECL_HASHKEYEQ ( hashKeyEqSols  )

static

returns TRUE iff both solution tuples are identical

Definition at line 125 of file heur_crossover.c.

References FALSE, NULL, and TRUE.

static SCIP_DECL_HASHKEYVAL ( hashKeyValSols  )

static

returns hashkey of a solution tuple

Definition at line 156 of file heur_crossover.c.

static unsigned int calculateHashKey ( int *  indices, int  size  )

static

calculates a hash key for a given tuple of solution indices

Parameters

indices	indices of solutions
size	number of solutions

Definition at line 164 of file heur_crossover.c.

Referenced by createSolTuple().

static void sortArray ( int *  a, int  size  )

static

insertion sort for a small int array

Parameters

a	array to be sorted
size	size of array

Definition at line 184 of file heur_crossover.c.

Referenced by createSolTuple().

static SCIP_RETCODE createSolTuple ( SCIP *  scip, SOLTUPLE **  elem, int *  indices, int  size, SCIP_HEURDATA *  heurdata  )

static

creates a new tuple of solutions

Parameters

scip	original SCIP data structure
elem	tuple of solutions which should be created
indices	indices of solutions
size	number of solutions
heurdata	primal heuristic data

Definition at line 210 of file heur_crossover.c.

References BMScopyMemoryArray, calculateHashKey(), SCIP_CALL, SCIP_OKAY, SCIPallocBlockMemory, SCIPallocBlockMemoryArray, and sortArray().

Referenced by SCIP_DECL_HEUREXEC(), selectSolsRandomized(), and setupSubproblem().

static SCIP_Bool solHasNewSource ( SCIP_SOL **  sols, int *  selection, int  selectionsize, int  newsol  )

static

Parameters

sols	feasible SCIP solutions
selection	pool of solutions crossover uses
selectionsize	size of solution pool
newsol	candidate solution

Definition at line 236 of file heur_crossover.c.

References FALSE, SCIPsolGetHeur(), SCIPsolGetNodenum(), and TRUE.

Referenced by selectSolsRandomized().

static SCIP_RETCODE selectSolsRandomized ( SCIP *  scip, int *  selection, SCIP_HEURDATA *  heurdata, SCIP_Bool *  success  )

static

randomly selects the solutions crossover will use from the pool of all solutions found so far

Parameters

scip	original SCIP data structure
selection	pool of solutions crossover uses
heurdata	primal heuristic data
success	pointer to store whether the process was successful

Definition at line 255 of file heur_crossover.c.

References createSolTuple(), FALSE, SCIP_Bool, SCIP_CALL, SCIP_OKAY, SCIPgetNSols(), SCIPgetRandomInt(), SCIPgetSols(), SCIPhashtableExists(), SCIPhashtableInsert(), solHasNewSource(), and TRUE.

Referenced by setupSubproblem().

static SCIP_RETCODE fixVariables ( SCIP *  scip, SCIP *  subscip, SCIP_VAR **  subvars, int *  selection, SCIP_HEURDATA *  heurdata, SCIP_Bool *  success  )

static

creates the all variables of the subproblem

Parameters

scip	original SCIP data structure
subscip	SCIP data structure for the subproblemd
subvars	the variables of the subproblem
selection	pool of solutions crossover will use
heurdata	primal heuristic data
success	pointer to store whether the problem was created successfully

Definition at line 320 of file heur_crossover.c.

References FALSE, MAX, NULL, REALABS, SCIP_Bool, SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIPchgVarLbGlobal(), SCIPchgVarUbGlobal(), SCIPgetSols(), SCIPgetSolVal(), SCIPgetVarsData(), SCIPvarGetLbGlobal(), SCIPvarGetUbGlobal(), and TRUE.

Referenced by setupSubproblem().

static SCIP_RETCODE createRows ( SCIP *  scip, SCIP *  subscip, SCIP_VAR **  subvars  )

static

creates the rows of the subproblem

Parameters

scip	original SCIP data structure
subscip	SCIP data structure for the subproblem
subvars	the variables of the subproblem

Definition at line 393 of file heur_crossover.c.

References FALSE, SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIPaddCons(), SCIPallocBufferArray, SCIPcolGetVar(), SCIPcreateConsLinear(), SCIPfreeBufferArray, SCIPgetLPRowsData(), SCIPreleaseCons(), SCIProwGetCols(), SCIProwGetConstant(), SCIProwGetLhs(), SCIProwGetName(), SCIProwGetNNonz(), SCIProwGetRhs(), SCIProwGetVals(), SCIProwIsLocal(), SCIPvarGetProbindex(), and TRUE.

Referenced by setupSubproblem().

static SCIP_RETCODE setupSubproblem ( SCIP *  scip, SCIP *  subscip, SCIP_VAR **  subvars, int *  selection, SCIP_HEURDATA *  heurdata, 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
selection	pool of solutions crossover will use
heurdata	primal heuristic data
success	pointer to store whether the problem was created successfully

Definition at line 454 of file heur_crossover.c.

References createRows(), createSolTuple(), FALSE, fixVariables(), SCIP_Bool, SCIP_CALL, SCIP_Longint, SCIP_MAXSTRLEN, SCIP_OKAY, SCIPgetNSols(), SCIPgetProbName(), SCIPgetSols(), SCIPhashtableExists(), SCIPhashtableInsert(), SCIPsnprintf(), SCIPsolGetHeur(), SCIPsolGetNodenum(), selectSolsRandomized(), and TRUE.

Referenced by SCIP_DECL_HEUREXEC().

static SCIP_RETCODE createNewSol ( SCIP *  scip, SCIP *  subscip, SCIP_VAR **  subvars, SCIP_HEUR *  heur, SCIP_SOL *  subsol, int *  solindex, 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	crossover heuristic structure
subsol	solution of the subproblem
solindex	index of the solution
success	used to store whether new solution was found or not

Definition at line 548 of file heur_crossover.c.

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

Referenced by SCIP_DECL_HEUREXEC().

static void updateFailureStatistic ( SCIP *  scip, SCIP_HEURDATA *  heurdata  )

static

updates heurdata after a run of crossover

Parameters

scip	original SCIP data structure
heurdata	primal heuristic data

Definition at line 595 of file heur_crossover.c.

References SCIP_LONGINT_MAX, and SCIPgetNNodes().

Referenced by SCIP_DECL_HEUREXEC().

static SCIP_DECL_EVENTEXEC ( eventExecCrossover  )

static

Definition at line 614 of file heur_crossover.c.

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

static SCIP_DECL_HEURCOPY ( heurCopyCrossover  )

static

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

Definition at line 643 of file heur_crossover.c.

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

static SCIP_DECL_HEURFREE ( heurFreeCrossover  )

static

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

Definition at line 657 of file heur_crossover.c.

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

static SCIP_DECL_HEURINIT ( heurInitCrossover  )

static

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

Definition at line 677 of file heur_crossover.c.

References HASHSIZE_SOLS, NULL, SCIP_CALL, SCIP_OKAY, SCIPblkmem(), SCIPhashtableCreate(), and SCIPheurGetData().

static SCIP_DECL_HEUREXIT ( heurExitCrossover  )

static

deinitialization method of primal heuristic (called before transformed problem is freed)

Definition at line 708 of file heur_crossover.c.

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

static SCIP_DECL_HEUREXEC ( heurExecCrossover  )

static

execution method of primal heuristic

Definition at line 741 of file heur_crossover.c.

References createNewSol(), createSolTuple(), EVENTHDLR_DESC, EVENTHDLR_NAME, FALSE, HEUR_NAME, MIN, NULL, SCIP_Bool, SCIP_CALL, SCIP_DELAYED, SCIP_DIDNOTFIND, SCIP_DIDNOTRUN, SCIP_EVENTTYPE_LPSOLVED, SCIP_FOUNDSOL, SCIP_Longint, 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(), SCIPgetDepth(), SCIPgetLowerbound(), SCIPgetMemExternEstim(), SCIPgetMemUsed(), SCIPgetNNodes(), SCIPgetNSols(), SCIPgetProbName(), SCIPgetRealParam(), SCIPgetSolNodenum(), SCIPgetSols(), SCIPgetSolvingTime(), SCIPgetUpperbound(), SCIPgetVarsData(), SCIPhashmapCreate(), SCIPhashmapFree(), SCIPhashmapGetImage(), SCIPhashtableInsert(), SCIPheurGetData(), SCIPheurGetNBestSolsFound(), SCIPheurGetNCalls(), SCIPincludeDefaultPlugins(), SCIPincludeEventhdlrBasic(), SCIPinfinity(), SCIPisInfinity(), SCIPisParamFixed(), SCIPisStopped(), SCIPpermuteProb(), SCIPprintStatistics(), SCIPsetBoolParam(), SCIPsetIntParam(), SCIPsetLongintParam(), SCIPsetObjlimit(), SCIPsetPresolving(), SCIPsetRealParam(), SCIPsetSeparating(), SCIPsetSubscipsOff(), SCIPsnprintf(), SCIPsolGetIndex(), SCIPsolve(), SCIPsumepsilon(), SCIPtransformProb(), SCIPwarningMessage(), setupSubproblem(), TRUE, and updateFailureStatistic().

SCIP_RETCODE SCIPincludeHeurCrossover

(

SCIP *

scip

)

creates the crossover primal heuristic and includes it in SCIP

Parameters

scip	SCIP data structure

Definition at line 1137 of file heur_crossover.c.

References DEFAULT_COPYCUTS, DEFAULT_DONTWAITATROOT, DEFAULT_LPLIMFAC, DEFAULT_MAXNODES, DEFAULT_MINFIXINGRATE, DEFAULT_MINIMPROVE, DEFAULT_MINNODES, DEFAULT_NODESOFS, DEFAULT_NODESQUOT, DEFAULT_NUSEDSOLS, DEFAULT_NWAITINGNODES, DEFAULT_PERMUTE, DEFAULT_RANDOMIZATION, 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(), SCIPsetHeurExit(), SCIPsetHeurFree(), SCIPsetHeurInit(), and TRUE.

Referenced by SCIP_DECL_HEURCOPY(), and SCIPincludeDefaultPlugins().