Scippy

SCIP

Solving Constraint Integer Programs

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

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
scipSCIP data structure
binvarsarray of binary variables to sort
nbinvarsnumber of binary variables
cliquepartitionclique partition to use
ncliquesnumber 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
sciporiginal SCIP data structure
heurdatastructure containing heurdata
binvarsbinary variables order w.r.t. to clique partition
nbinvarsnumber of binary variables
cliquepartitionclique partition of all binary variables
ncliquesnumber of cliques
onefixvarsarray to store all variables which are stored to one
nonefixvarspointer to store the number of variables fixed to one
solworking solution
probingdepthofonefixpointer to store in which depth the last fixing to was applied
cutoffpointer to store whether the propagation stopped with infeasibility
resultpointer 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
sciporiginal SCIP data structure
subscipSCIP structure of the subproblem
subvarsthe variables of the subproblem
newsolworking solution
subsolsolution of the subproblem
successused 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
scipSCIP data structure

Definition at line 1080 of file heur_clique.c.

Referenced by SCIPincludeDefaultPlugins().