heur_clique.c File Reference

Detailed Description

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

clique primal heuristic

Author

Stefan Heinz

Michael Winkler

Gerald Gamrath

More details about the heuristic can be found in
Structure-Based Primal Heuristics for Mixed Integer Programming
Gerald Gamrath, Timo Berthold, Stefan Heinz, and Michael Winkler
Optimization in the Real World, Volume 13 of the series Mathematics for Industry, pp 37-53
Preliminary version available as ZIB-Report 15-26.

Definition in file heur_clique.c.

#include "blockmemshell/memory.h"
#include "scip/cons_logicor.h"
#include "scip/heur_clique.h"
#include "scip/heur_locks.h"
#include "scip/pub_heur.h"
#include "scip/pub_implics.h"
#include "scip/pub_message.h"
#include "scip/pub_misc.h"
#include "scip/pub_misc_sort.h"
#include "scip/pub_var.h"
#include "scip/scip_branch.h"
#include "scip/scip_cons.h"
#include "scip/scip_copy.h"
#include "scip/scip_general.h"
#include "scip/scip_heur.h"
#include "scip/scip_lp.h"
#include "scip/scip_mem.h"
#include "scip/scip_message.h"
#include "scip/scip_numerics.h"
#include "scip/scip_param.h"
#include "scip/scip_prob.h"
#include "scip/scip_probing.h"
#include "scip/scip_sol.h"
#include "scip/scip_solve.h"
#include "scip/scip_solvingstats.h"
#include "scip/scip_timing.h"
#include "scip/scip_tree.h"
#include "scip/scip_var.h"
#include <string.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   5000
#define	HEUR_FREQ   0
#define	HEUR_FREQOFS   0
#define	HEUR_MAXDEPTH   -1
#define	HEUR_TIMING   SCIP_HEURTIMING_BEFORENODE
#define	HEUR_USESSUBSCIP   TRUE
#define	DEFAULT_MAXNODES   5000LL
#define	DEFAULT_MININTFIXINGRATE   0.65
#define	DEFAULT_MINMIPFIXINGRATE   0.65
#define	DEFAULT_MINIMPROVE   0.01
#define	DEFAULT_MINNODES   500LL
#define	DEFAULT_NODESOFS   500LL
#define	DEFAULT_NODESQUOT   0.1
#define	DEFAULT_MAXPROPROUNDS   2
#define	DEFAULT_MAXBACKTRACKS   10
#define	DEFAULT_COPYCUTS   TRUE
#define	DEFAULT_USELOCKFIXINGS   FALSE

Functions
static	SCIP_DECL_SORTINDCOMP (compCliquesSize)
static int	getCliqueUnfixedVars (SCIP_CLIQUE *clique)
static SCIP_RETCODE	applyCliqueFixings (SCIP *scip, SCIP_HEURDATA *heurdata, SCIP_Bool enabledconflicts, SCIP_VAR **onefixvars, SCIP_Shortbool *onefixvals, int *nonefixvars, SCIP_Bool *cutoff)
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

HEUR_NAME

#define HEUR_NAME   "clique"

Definition at line 66 of file heur_clique.c.

Referenced by createNewSol().

HEUR_DESC

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

Definition at line 67 of file heur_clique.c.

HEUR_DISPCHAR

#define HEUR_DISPCHAR   'Q'

Definition at line 68 of file heur_clique.c.

HEUR_PRIORITY

#define HEUR_PRIORITY   5000

Definition at line 69 of file heur_clique.c.

HEUR_FREQ

#define HEUR_FREQ   0

Definition at line 70 of file heur_clique.c.

HEUR_FREQOFS

#define HEUR_FREQOFS   0

Definition at line 71 of file heur_clique.c.

HEUR_MAXDEPTH

#define HEUR_MAXDEPTH   -1

Definition at line 72 of file heur_clique.c.

HEUR_TIMING

#define HEUR_TIMING   SCIP_HEURTIMING_BEFORENODE

Definition at line 73 of file heur_clique.c.

HEUR_USESSUBSCIP

#define HEUR_USESSUBSCIP   TRUE

does the heuristic use a secondary SCIP instance?

Definition at line 74 of file heur_clique.c.

DEFAULT_MAXNODES

#define DEFAULT_MAXNODES   5000LL

maximum number of nodes to regard in the subproblem

Definition at line 76 of file heur_clique.c.

DEFAULT_MININTFIXINGRATE

#define DEFAULT_MININTFIXINGRATE   0.65

minimum percentage of integer variables that have to be fixed

Definition at line 77 of file heur_clique.c.

DEFAULT_MINMIPFIXINGRATE

#define DEFAULT_MINMIPFIXINGRATE   0.65

minimum percentage of variables that have to be fixed within sub-SCIP (integer and continuous)

Definition at line 78 of file heur_clique.c.

DEFAULT_MINIMPROVE

#define DEFAULT_MINIMPROVE   0.01

factor by which clique heuristic should at least improve the incumbent

Definition at line 81 of file heur_clique.c.

DEFAULT_MINNODES

#define DEFAULT_MINNODES   500LL

minimum number of nodes to regard in the subproblem

Definition at line 86 of file heur_clique.c.

DEFAULT_NODESOFS

#define DEFAULT_NODESOFS   500LL

number of nodes added to the contingent of the total nodes

Definition at line 87 of file heur_clique.c.

DEFAULT_NODESQUOT

#define DEFAULT_NODESQUOT   0.1

subproblem nodes in relation to nodes of the original problem

Definition at line 88 of file heur_clique.c.

DEFAULT_MAXPROPROUNDS

#define DEFAULT_MAXPROPROUNDS   2

maximum number of propagation rounds during probing

Definition at line 89 of file heur_clique.c.

DEFAULT_MAXBACKTRACKS

#define DEFAULT_MAXBACKTRACKS   10

maximum number of backtracks during the fixing process

Definition at line 90 of file heur_clique.c.

DEFAULT_COPYCUTS

#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 91 of file heur_clique.c.

DEFAULT_USELOCKFIXINGS

#define DEFAULT_USELOCKFIXINGS   FALSE

should more variables be fixed based on variable locks if the fixing rate was not reached?

Definition at line 96 of file heur_clique.c.

Function Documentation

SCIP_DECL_SORTINDCOMP()

static SCIP_DECL_SORTINDCOMP ( compCliquesSize  )

static

comparison method for sorting cliques by their size

Definition at line 135 of file heur_clique.c.

getCliqueUnfixedVars()

static int getCliqueUnfixedVars ( SCIP_CLIQUE *  clique )

static

Definition at line 143 of file heur_clique.c.

Referenced by applyCliqueFixings().

applyCliqueFixings()

static SCIP_RETCODE applyCliqueFixings ( SCIP *  scip, SCIP_HEURDATA *  heurdata, SCIP_Bool  enabledconflicts, SCIP_VAR **  onefixvars, SCIP_Shortbool *  onefixvals, int *  nonefixvars, SCIP_Bool *  cutoff  )

static

apply clique fixing using probing

Parameters

scip	original SCIP data structure
heurdata	structure containing heurdata
enabledconflicts	was conflict analysis enabled before the heuristic call?
onefixvars	array to store all variables which are fixed to one in the cliques
onefixvals	array to store the values of all variables fixed to one in the cliques
nonefixvars	pointer to store the number of variables fixed to one
cutoff	pointer to store whether the propagation stopped with infeasibility

Definition at line 170 of file heur_clique.c.

References createNewSol(), FALSE, getCliqueUnfixedVars(), NULL, SCIP_Bool, SCIP_CALL, SCIP_CONFTYPE_PROPAGATION, SCIP_LONGINT_FORMAT, SCIP_MAXSTRLEN, SCIP_MAXTREEDEPTH, SCIP_OKAY, SCIP_Real, SCIPaddConflict(), SCIPallocBufferArray, SCIPallocClearBufferArray, SCIPbacktrackProbing(), SCIPcliqueGetNVars(), SCIPcliqueGetValues(), SCIPcliqueGetVars(), SCIPcreateConsLogicor(), SCIPdebugMessage, SCIPdebugMsg, SCIPdebugPrintCons, SCIPfixVarProbing(), SCIPfreeBufferArray, SCIPgetCliques(), SCIPgetDepth(), SCIPgetFocusNode(), SCIPgetNBinVars(), SCIPgetNCliques(), SCIPgetNegatedVar(), SCIPgetNNodes(), SCIPgetProbingDepth(), SCIPinfinity(), SCIPisStopped(), SCIPnewProbingNode(), SCIPpropagateProbing(), SCIPsnprintf(), SCIPsort(), SCIPvarGetLbLocal(), SCIPvarGetName(), SCIPvarGetObj(), SCIPvarGetUbLocal(), and TRUE.

createNewSol()

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 512 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().

SCIP_DECL_HEURCOPY()

static SCIP_DECL_HEURCOPY ( heurCopyClique  )

static

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

Definition at line 560 of file heur_clique.c.

Referenced by createNewSol().

SCIP_DECL_HEURFREE()

static SCIP_DECL_HEURFREE ( heurFreeClique  )

static

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

Definition at line 574 of file heur_clique.c.

SCIP_DECL_HEURINIT()

static SCIP_DECL_HEURINIT ( heurInitClique  )

static

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

Definition at line 595 of file heur_clique.c.

SCIP_DECL_HEUREXEC()

static SCIP_DECL_HEUREXEC ( heurExecClique  )

static

execution method of primal heuristic

Definition at line 614 of file heur_clique.c.