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 "blockmemshell/memory.h"
#include "scip/heuristics.h"
#include "scip/heur_mutation.h"
#include "scip/pub_heur.h"
#include "scip/pub_message.h"
#include "scip/pub_misc.h"
#include "scip/pub_sol.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_mem.h"
#include "scip/scip_message.h"
#include "scip/scip_nodesel.h"
#include "scip/scip_numerics.h"
#include "scip/scip_param.h"
#include "scip/scip_prob.h"
#include "scip/scip_randnumgen.h"
#include "scip/scip_sol.h"
#include "scip/scip_solve.h"
#include "scip/scip_solvingstats.h"
#include <string.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   SCIP_HEURDISPCHAR_LNS
#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
#define	DEFAULT_MAXNODES   5000
#define	DEFAULT_MINIMPROVE   0.01
#define	DEFAULT_MINNODES   500
#define	DEFAULT_MINFIXINGRATE   0.8
#define	DEFAULT_NODESQUOT   0.1
#define	DEFAULT_NWAITINGNODES   200
#define	DEFAULT_USELPROWS   FALSE
#define	DEFAULT_COPYCUTS   TRUE
#define	DEFAULT_BESTSOLLIMIT   -1
#define	DEFAULT_USEUCT   FALSE
#define	DEFAULT_RANDSEED   19

Functions
static SCIP_RETCODE	determineVariableFixings (SCIP *scip, SCIP_VAR **fixedvars, SCIP_Real *fixedvals, int *nfixedvars, SCIP_Real minfixingrate, SCIP_RANDNUMGEN *randnumgen, SCIP_Bool *success)
static SCIP_RETCODE	setupAndSolveSubscipMutation (SCIP *scip, SCIP *subscip, SCIP_HEUR *heur, SCIP_VAR **fixedvars, SCIP_Real *fixedvals, int nfixedvars, SCIP_Longint nsubnodes, SCIP_RESULT *result)
static	SCIP_DECL_HEURCOPY (heurCopyMutation)
static	SCIP_DECL_HEURFREE (heurFreeMutation)
static	SCIP_DECL_HEURINIT (heurInitMutation)
static	SCIP_DECL_HEUREXIT (heurExitMutation)
static	SCIP_DECL_HEUREXEC (heurExecMutation)
SCIP_RETCODE	SCIPincludeHeurMutation (SCIP *scip)

Macro Definition Documentation

HEUR_NAME

#define HEUR_NAME   "mutation"

Definition at line 49 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

HEUR_DESC

#define HEUR_DESC   "mutation heuristic randomly fixing variables"

Definition at line 50 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

HEUR_DISPCHAR

#define HEUR_DISPCHAR   SCIP_HEURDISPCHAR_LNS

Definition at line 51 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

HEUR_PRIORITY

#define HEUR_PRIORITY   -1103000

Definition at line 52 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

HEUR_FREQ

#define HEUR_FREQ   -1

Definition at line 53 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

HEUR_FREQOFS

#define HEUR_FREQOFS   8

Definition at line 54 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

HEUR_MAXDEPTH

#define HEUR_MAXDEPTH   -1

Definition at line 55 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

HEUR_TIMING

#define HEUR_TIMING   SCIP_HEURTIMING_AFTERNODE

Definition at line 56 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

HEUR_USESSUBSCIP

#define HEUR_USESSUBSCIP   TRUE

does the heuristic use a secondary SCIP instance?

Definition at line 57 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

DEFAULT_NODESOFS

#define DEFAULT_NODESOFS   500

number of nodes added to the contingent of the total nodes

Definition at line 59 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

DEFAULT_MAXNODES

#define DEFAULT_MAXNODES   5000

maximum number of nodes to regard in the subproblem

Definition at line 60 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

DEFAULT_MINIMPROVE

#define DEFAULT_MINIMPROVE   0.01

factor by which Mutation should at least improve the incumbent

Definition at line 61 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

DEFAULT_MINNODES

#define DEFAULT_MINNODES   500

minimum number of nodes to regard in the subproblem

Definition at line 62 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

DEFAULT_MINFIXINGRATE

#define DEFAULT_MINFIXINGRATE   0.8

minimum percentage of integer variables that have to be fixed

Definition at line 63 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

DEFAULT_NODESQUOT

#define DEFAULT_NODESQUOT   0.1

subproblem nodes in relation to nodes of the original problem

Definition at line 64 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

DEFAULT_NWAITINGNODES

#define DEFAULT_NWAITINGNODES   200

number of nodes without incumbent change that heuristic should wait

Definition at line 65 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

DEFAULT_USELPROWS

#define DEFAULT_USELPROWS   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 66 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

DEFAULT_COPYCUTS

#define DEFAULT_COPYCUTS   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 69 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

DEFAULT_BESTSOLLIMIT

#define DEFAULT_BESTSOLLIMIT   -1

limit on number of improving incumbent solutions in sub-CIP

Definition at line 72 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

DEFAULT_USEUCT

#define DEFAULT_USEUCT   FALSE

should uct node selection be used at the beginning of the search?

Definition at line 73 of file heur_mutation.c.

Referenced by SCIPincludeHeurMutation().

DEFAULT_RANDSEED

#define DEFAULT_RANDSEED   19

initial random seed

Definition at line 74 of file heur_mutation.c.

Function Documentation

determineVariableFixings()

static SCIP_RETCODE determineVariableFixings ( SCIP *  scip, SCIP_VAR **  fixedvars, SCIP_Real *  fixedvals, int *  nfixedvars, SCIP_Real  minfixingrate, SCIP_RANDNUMGEN *  randnumgen, SCIP_Bool *  success  )

static

determine variables and values which should be fixed in the mutation subproblem

Parameters

scip	original SCIP data structure
fixedvars	array to store the variables that should be fixed in the subproblem
fixedvals	array to store the fixing values to fix variables in the subproblem
nfixedvars	pointer to store the number of variables that should be fixed
minfixingrate	percentage of integer variables that have to be fixed
randnumgen	random number generator
success	used to store whether the creation of the subproblem worked

Definition at line 106 of file heur_mutation.c.

References BMScopyMemoryArray, FALSE, NULL, REALABS, SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIPgetBestSol(), SCIPgetSolVal(), SCIPgetVarsData(), SCIPisGT(), SCIPisInfinity(), SCIPisLE(), SCIPisLT(), SCIPrandomPermuteArray(), SCIPvarGetLbGlobal(), SCIPvarGetUbGlobal(), setupAndSolveSubscipMutation(), and TRUE.

setupAndSolveSubscipMutation()

static SCIP_RETCODE setupAndSolveSubscipMutation ( SCIP *  scip, SCIP *  subscip, SCIP_HEUR *  heur, SCIP_VAR **  fixedvars, SCIP_Real *  fixedvals, int  nfixedvars, SCIP_Longint  nsubnodes, SCIP_RESULT *  result  )

static

setup and solve mutation sub-SCIP

Parameters

scip	SCIP data structure
subscip	sub-SCIP data structure
heur	mutation heuristic
fixedvars	array to store the variables that should be fixed in the subproblem
fixedvals	array to store the fixing values to fix variables in the subproblem
nfixedvars	the number of variables that should be fixed
nsubnodes	node limit for the subproblem
result	pointer to store the result

Definition at line 188 of file heur_mutation.c.

References FALSE, NULL, SCIP_Bool, SCIP_CALL, SCIP_CALL_ABORT, SCIP_DECL_HEURCOPY(), SCIP_FOUNDSOL, SCIP_OKAY, SCIP_PARAMSETTING_FAST, SCIP_PARAMSETTING_OFF, SCIP_Real, SCIPallocBufferArray, SCIPblkmem(), SCIPcopyLargeNeighborhoodSearch(), SCIPcopyLimits(), SCIPdebug, SCIPdebugMsg, SCIPfindBranchrule(), SCIPfindConshdlr(), SCIPfindNodesel(), SCIPfreeBufferArray, SCIPgetLowerbound(), SCIPgetNNodes(), SCIPgetNVars(), SCIPgetUpperbound(), SCIPgetVars(), SCIPhashmapCreate(), SCIPhashmapFree(), SCIPhashmapGetImage(), SCIPheurGetData(), SCIPisInfinity(), SCIPisParamFixed(), SCIPmergeVariableStatistics(), SCIPprintStatistics(), SCIPsetBoolParam(), SCIPsetCharParam(), SCIPsetIntParam(), SCIPsetLongintParam(), SCIPsetObjlimit(), SCIPsetPresolving(), SCIPsetSeparating(), SCIPsetSubscipsOff(), SCIPsolve(), SCIPsumepsilon(), SCIPtranslateSubSols(), and TRUE.

Referenced by determineVariableFixings().

SCIP_DECL_HEURCOPY()

static SCIP_DECL_HEURCOPY ( heurCopyMutation  )

static

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

Definition at line 364 of file heur_mutation.c.

Referenced by setupAndSolveSubscipMutation().

SCIP_DECL_HEURFREE()

static SCIP_DECL_HEURFREE ( heurFreeMutation  )

static

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

Definition at line 378 of file heur_mutation.c.

SCIP_DECL_HEURINIT()

static SCIP_DECL_HEURINIT ( heurInitMutation  )

static

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

Definition at line 398 of file heur_mutation.c.

SCIP_DECL_HEUREXIT()

static SCIP_DECL_HEUREXIT ( heurExitMutation  )

static

deinitialization method of primal heuristic

Definition at line 421 of file heur_mutation.c.

SCIP_DECL_HEUREXEC()

static SCIP_DECL_HEUREXEC ( heurExecMutation  )

static

execution method of primal heuristic

Definition at line 440 of file heur_mutation.c.