Detailed Description

LNS heuristic using a clique partition to restrict the search neighborhood.

clique primal heuristic

Author: Stefan Heinz; Michael Winkler

Definition in file heur_clique.c.

#include <assert.h>
#include <string.h>
#include "scip/scip.h"
#include "scip/heur_clique.h"
#include "scip/cons_logicor.h"

Go to the source code of this file.

Macros
#define	HEUR_NAME "clique"

#define	HEUR_DESC "LNS heuristic using a clique partition to restrict the search neighborhood"

#define	HEUR_DISPCHAR 'Q'

#define	HEUR_PRIORITY -1000500

#define	HEUR_FREQ -1

#define	HEUR_FREQOFS 0

#define	HEUR_MAXDEPTH -1

#define	HEUR_TIMING SCIP_HEURTIMING_BEFORENODE

#define	HEUR_USESSUBSCIP TRUE

#define	DEFAULT_MAXNODES 5000LL

#define	DEFAULT_MINFIXINGRATE 0.25

#define	DEFAULT_MINIMPROVE 0.01

#define	DEFAULT_MINNODES 500LL

#define	DEFAULT_NODESOFS 500LL

#define	DEFAULT_NODESQUOT 0.1

#define	DEFAULT_MAXPROPROUNDS 2

#define	DEFAULT_INITSEED 0

#define	DEFAULT_MULTIPLIER 1.1

#define	DEFAULT_COPYCUTS TRUE

Functions
static	SCIP_DECL_SORTPTRCOMP (varObjSort)

static SCIP_RETCODE	stableSortBinvars (SCIP scip, SCIP_VAR binvars, int nbinvars, int cliquepartition, int ncliques)

static SCIP_RETCODE	applyCliqueFixings (SCIP scip, SCIP_HEURDATA heurdata, SCIP_VAR *binvars, int nbinvars, int cliquepartition, int ncliques, SCIP_VAR *onefixvars, int nonefixvars, SCIP_SOL sol, int probingdepthofonefix, SCIP_Bool cutoff, SCIP_RESULT result)

static SCIP_RETCODE	createNewSol (SCIP scip, SCIP subscip, SCIP_VAR *subvars, SCIP_SOL newsol, SCIP_SOL subsol, SCIP_Bool success)

static	SCIP_DECL_HEURCOPY (heurCopyClique)

static	SCIP_DECL_HEURFREE (heurFreeClique)

static	SCIP_DECL_HEURINIT (heurInitClique)

static	SCIP_DECL_HEUREXEC (heurExecClique)

SCIP_RETCODE	SCIPincludeHeurClique (SCIP *scip)

Macro Definition Documentation

#define HEUR_NAME "clique"

Definition at line 36 of file heur_clique.c.

Referenced by createNewSol().

#define HEUR_DESC "LNS heuristic using a clique partition to restrict the search neighborhood"

Definition at line 37 of file heur_clique.c.

#define HEUR_DISPCHAR 'Q'

Definition at line 38 of file heur_clique.c.

#define HEUR_PRIORITY -1000500

Definition at line 39 of file heur_clique.c.

#define HEUR_FREQ -1

Definition at line 40 of file heur_clique.c.

#define HEUR_FREQOFS 0

Definition at line 41 of file heur_clique.c.

#define HEUR_MAXDEPTH -1

Definition at line 42 of file heur_clique.c.

#define HEUR_TIMING SCIP_HEURTIMING_BEFORENODE

Definition at line 43 of file heur_clique.c.

#define HEUR_USESSUBSCIP TRUE

does the heuristic use a secondary SCIP instance?

Definition at line 44 of file heur_clique.c.

#define DEFAULT_MAXNODES 5000LL

maximum number of nodes to regard in the subproblem

Definition at line 46 of file heur_clique.c.

#define DEFAULT_MINFIXINGRATE 0.25

minimum percentage of variables that have to be fixed

Definition at line 47 of file heur_clique.c.

#define DEFAULT_MINIMPROVE 0.01

factor by which clique heuristic should at least improve the incumbent

Definition at line 48 of file heur_clique.c.

#define DEFAULT_MINNODES 500LL

minimum number of nodes to regard in the subproblem

Definition at line 53 of file heur_clique.c.

#define DEFAULT_NODESOFS 500LL

number of nodes added to the contingent of the total nodes

Definition at line 54 of file heur_clique.c.

#define DEFAULT_NODESQUOT 0.1

subproblem nodes in relation to nodes of the original problem

Definition at line 55 of file heur_clique.c.

#define DEFAULT_MAXPROPROUNDS 2

maximum number of propagation rounds during probing

Definition at line 56 of file heur_clique.c.

#define DEFAULT_INITSEED 0

random seed value to initialize the random permutation value for variables

Definition at line 57 of file heur_clique.c.

#define DEFAULT_MULTIPLIER 1.1

value to increase node number to determine the next run

Definition at line 62 of file heur_clique.c.

#define DEFAULT_COPYCUTS TRUE

should all active cuts from the cutpool of the original scip be copied to constraints of the subscip

Definition at line 63 of file heur_clique.c.

Function Documentation

static SCIP_DECL_SORTPTRCOMP ( varObjSort )

static

comparison method for sorting variables by non-decreasing index

Definition at line 100 of file heur_clique.c.

static SCIP_RETCODE stableSortBinvars	(	SCIP *	scip,
		SCIP_VAR **	binvars,
		int	nbinvars,
		int *	cliquepartition,
		int	ncliques
	)

static

sort the binary variable array w.r.t. the clique partition; thereby ensure the current order within the cliques are not changed

Parameters

scip	SCIP data structure
binvars	array of binary variables to sort
nbinvars	number of binary variables
cliquepartition	clique partition to use
ncliques	number of cliques

Definition at line 123 of file heur_clique.c.

References applyCliqueFixings(), BMSclearMemoryArray, BMScopyMemoryArray, NULL, SCIP_CALL, SCIP_OKAY, SCIPallocBufferArray, SCIPfreeBufferArray, and SCIPvarGetObj().

static SCIP_RETCODE applyCliqueFixings	(	SCIP *	scip,
		SCIP_HEURDATA *	heurdata,
		SCIP_VAR **	binvars,
		int	nbinvars,
		int *	cliquepartition,
		int	ncliques,
		SCIP_VAR **	onefixvars,
		int *	nonefixvars,
		SCIP_SOL *	sol,
		int *	probingdepthofonefix,
		SCIP_Bool *	cutoff,
		SCIP_RESULT *	result
	)

static

apply clique fixing using probing

Parameters

scip	original SCIP data structure
heurdata	structure containing heurdata
binvars	binary variables order w.r.t. to clique partition
nbinvars	number of binary variables
cliquepartition	clique partition of all binary variables
ncliques	number of cliques
onefixvars	array to store all variables which are stored to one
nonefixvars	pointer to store the number of variables fixed to one
sol	working solution
probingdepthofonefix	pointer to store in which depth the last fixing to was applied
cutoff	pointer to store whether the propagation stopped with infeasibility
result	pointer to store the result (solution found)

Definition at line 225 of file heur_clique.c.

References createNewSol(), FALSE, NULL, SCIP_Bool, SCIP_CALL, SCIP_FOUNDSOL, SCIP_OKAY, SCIPdebugMessage, SCIPfixVarProbing(), SCIPgetDepth(), SCIPgetDepthLimit(), SCIPgetProbingDepth(), SCIPgetSolOrigObj(), SCIPisStopped(), SCIPlinkCurrentSol(), SCIPnewProbingNode(), SCIPpropagateProbing(), SCIProundSol(), SCIPtrySol(), SCIPvarGetLbLocal(), SCIPvarGetName(), SCIPvarGetUbLocal(), and TRUE.

Referenced by stableSortBinvars().

static SCIP_RETCODE createNewSol	(	SCIP *	scip,
		SCIP *	subscip,
		SCIP_VAR **	subvars,
		SCIP_SOL *	newsol,
		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
newsol	working solution
subsol	solution of the subproblem
success	used to store whether new solution was found or not

Definition at line 390 of file heur_clique.c.

References FALSE, HEUR_NAME, NULL, SCIP_CALL, SCIP_DECL_HEURCOPY(), SCIP_OKAY, SCIP_Real, SCIPallocBufferArray, SCIPfreeBufferArray, SCIPgetNOrigVars(), SCIPgetSolVals(), SCIPgetVarsData(), SCIPheurGetName(), SCIPsetSolVals(), SCIPtrySol(), and TRUE.

Referenced by applyCliqueFixings().

static SCIP_DECL_HEURCOPY ( heurCopyClique )

static

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

Definition at line 438 of file heur_clique.c.

Referenced by createNewSol().

static SCIP_DECL_HEURFREE ( heurFreeClique )

static

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

Definition at line 452 of file heur_clique.c.

static SCIP_DECL_HEURINIT ( heurInitClique )

static

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

Definition at line 473 of file heur_clique.c.

static SCIP_DECL_HEUREXEC ( heurExecClique )

static

execution method of primal heuristic

Definition at line 496 of file heur_clique.c.

SCIP_RETCODE SCIPincludeHeurClique ( SCIP * scip )

creates the clique primal heuristic and includes it in SCIP

Parameters

scip	SCIP data structure

Definition at line 1080 of file heur_clique.c.

Referenced by SCIPincludeDefaultPlugins().

SCIP

Detailed Description

Macros

Functions

Macro Definition Documentation

Function Documentation