heur_mutation.c File Reference

Detailed Description

LNS heuristic that tries to randomly mutate the incumbent solution.

Author

Timo Berthold

Definition in file heur_mutation.c.

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

Go to the source code of this file.

Macros
#define	HEUR_NAME   "mutation"
#define	HEUR_DESC   "mutation heuristic randomly fixing variables"
#define	HEUR_DISPCHAR   'M'
#define	HEUR_PRIORITY   -1103000
#define	HEUR_FREQ   -1
#define	HEUR_FREQOFS   8
#define	HEUR_MAXDEPTH   -1
#define	HEUR_TIMING   SCIP_HEURTIMING_AFTERNODE
#define	HEUR_USESSUBSCIP   TRUE
#define	DEFAULT_NODESOFS   500 /* number of nodes added to the contingent of the total nodes */
#define	DEFAULT_MAXNODES   5000 /* maximum number of nodes to regard in the subproblem */
#define	DEFAULT_MINIMPROVE   0.01 /* factor by which Mutation should at least improve the incumbent */
#define	DEFAULT_MINNODES   500 /* minimum number of nodes to regard in the subproblem */
#define	DEFAULT_MINFIXINGRATE   0.8 /* minimum percentage of integer variables that have to be fixed */
#define	DEFAULT_NODESQUOT   0.1 /* subproblem nodes in relation to nodes of the original problem */
#define	DEFAULT_NWAITINGNODES   200 /* number of nodes without incumbent change that heuristic should wait */
#define	DEFAULT_USELPROWS
#define	DEFAULT_COPYCUTS

Functions
static SCIP_RETCODE	createSubproblem (SCIP *scip, SCIP *subscip, SCIP_VAR **subvars, SCIP_Real minfixingrate, unsigned int *randseed, SCIP_Bool uselprows)
static SCIP_RETCODE	createNewSol (SCIP *scip, SCIP *subscip, SCIP_VAR **subvars, SCIP_HEUR *heur, SCIP_SOL *subsol, SCIP_Bool *success)
static	SCIP_DECL_HEURCOPY (heurCopyMutation)
static	SCIP_DECL_HEURFREE (heurFreeMutation)
static	SCIP_DECL_HEURINIT (heurInitMutation)
static	SCIP_DECL_HEUREXEC (heurExecMutation)
SCIP_RETCODE	SCIPincludeHeurMutation (SCIP *scip)

Macro Definition Documentation

#define HEUR_NAME   "mutation"

Definition at line 31 of file heur_mutation.c.

Referenced by SCIP_DECL_HEURCOPY(), and SCIPincludeHeurMutation().

#define HEUR_DESC   "mutation heuristic randomly fixing variables"

Definition at line 32 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

#define HEUR_DISPCHAR   'M'

Definition at line 33 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

#define HEUR_PRIORITY   -1103000

Definition at line 34 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

#define HEUR_FREQ   -1

Definition at line 35 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

#define HEUR_FREQOFS   8

Definition at line 36 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

#define HEUR_MAXDEPTH   -1

Definition at line 37 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

#define HEUR_TIMING   SCIP_HEURTIMING_AFTERNODE

Definition at line 38 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

#define HEUR_USESSUBSCIP   TRUE

does the heuristic use a secondary SCIP instance?

Definition at line 39 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

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

Definition at line 41 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

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

Definition at line 42 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

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

Definition at line 43 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

#define DEFAULT_MINNODES   500 /* minimum number of nodes to regard in the subproblem */

Definition at line 44 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

#define DEFAULT_MINFIXINGRATE   0.8 /* minimum percentage of integer variables that have to be fixed */

Definition at line 45 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

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

Definition at line 46 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

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

Definition at line 47 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

#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 48 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

#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 49 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

Function Documentation

static SCIP_RETCODE createSubproblem ( SCIP *  scip, SCIP *  subscip, SCIP_VAR **  subvars, SCIP_Real  minfixingrate, unsigned int *  randseed, SCIP_Bool  uselprows  )

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
minfixingrate	percentage of integer variables that have to be fixed
randseed	a seed value for the random number generator
uselprows	should subproblem be created out of the rows in the LP rows?

Definition at line 81 of file heur_mutation.c.

References BMSclearMemoryArray, FALSE, NULL, SCIP_Bool, SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIPaddCons(), SCIPallocBufferArray, SCIPceil(), SCIPchgVarLbGlobal(), SCIPchgVarUbGlobal(), SCIPcolGetVar(), SCIPcreateConsLinear(), SCIPfloor(), SCIPfreeBufferArray, SCIPgetBestSol(), SCIPgetLPRowsData(), SCIPgetRandomInt(), SCIPgetSolVal(), SCIPgetVarsData(), SCIPisGT(), SCIPisInfinity(), SCIPisLE(), SCIPisLT(), SCIPreleaseCons(), SCIProwGetCols(), SCIProwGetConstant(), SCIProwGetLhs(), SCIProwGetName(), SCIProwGetNNonz(), SCIProwGetRhs(), SCIProwGetVals(), SCIProwIsLocal(), SCIPvarGetLbGlobal(), SCIPvarGetProbindex(), SCIPvarGetUbGlobal(), 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	mutation heuristic structure
subsol	solution of the subproblem
success	used to store whether new solution was found or not

Definition at line 223 of file heur_mutation.c.

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

Referenced by SCIP_DECL_HEUREXEC().

static SCIP_DECL_HEURCOPY ( heurCopyMutation  )

static

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

Definition at line 273 of file heur_mutation.c.

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

static SCIP_DECL_HEURFREE ( heurFreeMutation  )

static

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

Definition at line 287 of file heur_mutation.c.

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

static SCIP_DECL_HEURINIT ( heurInitMutation  )

static

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

Definition at line 307 of file heur_mutation.c.

References NULL, SCIP_OKAY, and SCIPheurGetData().

static SCIP_DECL_HEUREXEC ( heurExecMutation  )

static

execution method of primal heuristic

Definition at line 328 of file heur_mutation.c.

References createNewSol(), createSubproblem(), FALSE, MIN, NULL, SCIP_Bool, SCIP_CALL, SCIP_DELAYED, SCIP_DIDNOTFIND, SCIP_DIDNOTRUN, SCIP_FOUNDSOL, SCIP_Longint, SCIP_MAXSTRLEN, SCIP_OKAY, SCIP_PARAMSETTING_FAST, SCIP_PARAMSETTING_OFF, SCIP_Real, SCIPallocBufferArray, SCIPblkmem(), SCIPcalcHashtableSize(), SCIPcopy(), SCIPcopyCuts(), SCIPcopyVars(), SCIPcreate(), SCIPcreateProb(), SCIPdebugMessage, SCIPfindBranchrule(), SCIPfindConshdlr(), SCIPfindNodesel(), SCIPfree(), SCIPfreeBufferArray, SCIPgetBestSol(), SCIPgetLowerbound(), SCIPgetMemExternEstim(), SCIPgetMemUsed(), SCIPgetNBinVars(), SCIPgetNIntVars(), SCIPgetNNodes(), SCIPgetNSols(), SCIPgetProbName(), SCIPgetRealParam(), SCIPgetSolNodenum(), SCIPgetSols(), SCIPgetSolvingTime(), SCIPgetUpperbound(), SCIPgetVarsData(), SCIPhashmapCreate(), SCIPhashmapFree(), SCIPhashmapGetImage(), SCIPheurGetData(), SCIPheurGetNBestSolsFound(), SCIPheurGetNCalls(), SCIPincludeDefaultPlugins(), SCIPinfinity(), SCIPisInfinity(), SCIPisParamFixed(), SCIPisStopped(), SCIPsetBoolParam(), SCIPsetIntParam(), SCIPsetLongintParam(), SCIPsetObjlimit(), SCIPsetPresolving(), SCIPsetRealParam(), SCIPsetSeparating(), SCIPsetSubscipsOff(), SCIPsnprintf(), SCIPsolIsOriginal(), SCIPsolve(), SCIPsumepsilon(), SCIPwarningMessage(), and TRUE.

SCIP_RETCODE SCIPincludeHeurMutation

(

SCIP *

scip

)

creates the mutation primal heuristic and includes it in SCIP

Parameters

scip	SCIP data structure

Definition at line 603 of file heur_mutation.c.

References DEFAULT_COPYCUTS, DEFAULT_MAXNODES, DEFAULT_MINFIXINGRATE, DEFAULT_MINIMPROVE, DEFAULT_MINNODES, DEFAULT_NODESOFS, DEFAULT_NODESQUOT, DEFAULT_NWAITINGNODES, 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_OKAY, SCIPaddBoolParam(), SCIPaddIntParam(), SCIPaddRealParam(), SCIPallocMemory, SCIPincludeHeurBasic(), SCIPsetHeurCopy(), SCIPsetHeurFree(), SCIPsetHeurInit(), SCIPsumepsilon(), and TRUE.

Referenced by SCIP_DECL_HEURCOPY(), and SCIPincludeDefaultPlugins().