heur_fracdiving.c File Reference

Detailed Description

LP diving heuristic that chooses fixings w.r.t. the fractionalities.

Author

Tobias Achterberg

Definition in file heur_fracdiving.c.

#include <assert.h>
#include <string.h>
#include "scip/heur_fracdiving.h"

Go to the source code of this file.

Macros
#define	HEUR_NAME   "fracdiving"
#define	HEUR_DESC   "LP diving heuristic that chooses fixings w.r.t. the fractionalities"
#define	HEUR_DISPCHAR   'f'
#define	HEUR_PRIORITY   -1003000
#define	HEUR_FREQ   10
#define	HEUR_FREQOFS   3
#define	HEUR_MAXDEPTH   -1
#define	HEUR_TIMING   SCIP_HEURTIMING_AFTERLPPLUNGE
#define	HEUR_USESSUBSCIP   FALSE
#define	DIVESET_DIVETYPES   SCIP_DIVETYPE_INTEGRALITY | SCIP_DIVETYPE_SOS1VARIABLE
#define	DEFAULT_MINRELDEPTH   0.0
#define	DEFAULT_MAXRELDEPTH   1.0
#define	DEFAULT_MAXLPITERQUOT   0.05
#define	DEFAULT_MAXLPITEROFS   1000
#define	DEFAULT_MAXDIVEUBQUOT   0.8
#define	DEFAULT_MAXDIVEAVGQUOT   0.0
#define	DEFAULT_MAXDIVEUBQUOTNOSOL   0.1
#define	DEFAULT_MAXDIVEAVGQUOTNOSOL   0.0
#define	DEFAULT_BACKTRACK   TRUE
#define	DEFAULT_LPRESOLVEDOMCHGQUOT   0.15
#define	DEFAULT_LPSOLVEFREQ   0
#define	DEFAULT_ONLYLPBRANCHCANDS   FALSE
#define	DEFAULT_RANDSEED   89

Functions
static	SCIP_DECL_HEURCOPY (heurCopyFracdiving)
static	SCIP_DECL_HEURFREE (heurFreeFracdiving)
static	SCIP_DECL_HEURINIT (heurInitFracdiving)
static	SCIP_DECL_HEUREXIT (heurExitFracdiving)
static	SCIP_DECL_HEUREXEC (heurExecFracdiving)
static	SCIP_DECL_DIVESETGETSCORE (divesetGetScoreFracdiving)
SCIP_RETCODE	SCIPincludeHeurFracdiving (SCIP *scip)

Macro Definition Documentation

HEUR_NAME

#define HEUR_NAME   "fracdiving"

Definition at line 28 of file heur_fracdiving.c.

Referenced by SCIPincludeHeurFracdiving().

HEUR_DESC

#define HEUR_DESC   "LP diving heuristic that chooses fixings w.r.t. the fractionalities"

Definition at line 29 of file heur_fracdiving.c.

Referenced by SCIPincludeHeurFracdiving().

HEUR_DISPCHAR

#define HEUR_DISPCHAR   'f'

Definition at line 30 of file heur_fracdiving.c.

Referenced by SCIPincludeHeurFracdiving().

HEUR_PRIORITY

#define HEUR_PRIORITY   -1003000

Definition at line 31 of file heur_fracdiving.c.

Referenced by SCIPincludeHeurFracdiving().

HEUR_FREQ

#define HEUR_FREQ   10

Definition at line 32 of file heur_fracdiving.c.

Referenced by SCIPincludeHeurFracdiving().

HEUR_FREQOFS

#define HEUR_FREQOFS   3

Definition at line 33 of file heur_fracdiving.c.

Referenced by SCIPincludeHeurFracdiving().

HEUR_MAXDEPTH

#define HEUR_MAXDEPTH   -1

Definition at line 34 of file heur_fracdiving.c.

Referenced by SCIPincludeHeurFracdiving().

HEUR_TIMING

#define HEUR_TIMING   SCIP_HEURTIMING_AFTERLPPLUNGE

Definition at line 35 of file heur_fracdiving.c.

Referenced by SCIPincludeHeurFracdiving().

HEUR_USESSUBSCIP

#define HEUR_USESSUBSCIP   FALSE

does the heuristic use a secondary SCIP instance?

Definition at line 36 of file heur_fracdiving.c.

Referenced by SCIPincludeHeurFracdiving().

DIVESET_DIVETYPES

#define DIVESET_DIVETYPES   SCIP_DIVETYPE_INTEGRALITY | SCIP_DIVETYPE_SOS1VARIABLE

bit mask that represents all supported dive types

Definition at line 37 of file heur_fracdiving.c.

Referenced by SCIPincludeHeurFracdiving().

DEFAULT_MINRELDEPTH

#define DEFAULT_MINRELDEPTH   0.0

minimal relative depth to start diving

Definition at line 44 of file heur_fracdiving.c.

Referenced by SCIPincludeHeurFracdiving().

DEFAULT_MAXRELDEPTH

#define DEFAULT_MAXRELDEPTH   1.0

maximal relative depth to start diving

Definition at line 45 of file heur_fracdiving.c.

Referenced by SCIPincludeHeurFracdiving().

DEFAULT_MAXLPITERQUOT

#define DEFAULT_MAXLPITERQUOT   0.05

maximal fraction of diving LP iterations compared to node LP iterations

Definition at line 46 of file heur_fracdiving.c.

Referenced by SCIPincludeHeurFracdiving().

DEFAULT_MAXLPITEROFS

#define DEFAULT_MAXLPITEROFS   1000

additional number of allowed LP iterations

Definition at line 47 of file heur_fracdiving.c.

Referenced by SCIPincludeHeurFracdiving().

DEFAULT_MAXDIVEUBQUOT

#define DEFAULT_MAXDIVEUBQUOT   0.8

maximal quotient (curlowerbound - lowerbound)/(cutoffbound - lowerbound) where diving is performed (0.0: no limit)

Definition at line 48 of file heur_fracdiving.c.

Referenced by SCIPincludeHeurFracdiving().

DEFAULT_MAXDIVEAVGQUOT

#define DEFAULT_MAXDIVEAVGQUOT   0.0

maximal quotient (curlowerbound - lowerbound)/(avglowerbound - lowerbound) where diving is performed (0.0: no limit)

Definition at line 51 of file heur_fracdiving.c.

Referenced by SCIPincludeHeurFracdiving().

DEFAULT_MAXDIVEUBQUOTNOSOL

#define DEFAULT_MAXDIVEUBQUOTNOSOL   0.1

maximal UBQUOT when no solution was found yet (0.0: no limit)

Definition at line 54 of file heur_fracdiving.c.

Referenced by SCIPincludeHeurFracdiving().

DEFAULT_MAXDIVEAVGQUOTNOSOL

#define DEFAULT_MAXDIVEAVGQUOTNOSOL   0.0

maximal AVGQUOT when no solution was found yet (0.0: no limit)

Definition at line 55 of file heur_fracdiving.c.

Referenced by SCIPincludeHeurFracdiving().

DEFAULT_BACKTRACK

#define DEFAULT_BACKTRACK   TRUE

use one level of backtracking if infeasibility is encountered?

Definition at line 56 of file heur_fracdiving.c.

Referenced by SCIPincludeHeurFracdiving().

DEFAULT_LPRESOLVEDOMCHGQUOT

#define DEFAULT_LPRESOLVEDOMCHGQUOT   0.15

percentage of immediate domain changes during probing to trigger LP resolve

Definition at line 58 of file heur_fracdiving.c.

Referenced by SCIPincludeHeurFracdiving().

DEFAULT_LPSOLVEFREQ

#define DEFAULT_LPSOLVEFREQ   0

LP solve frequency for diving heuristics

Definition at line 59 of file heur_fracdiving.c.

Referenced by SCIPincludeHeurFracdiving().

DEFAULT_ONLYLPBRANCHCANDS

#define DEFAULT_ONLYLPBRANCHCANDS   FALSE

should only LP branching candidates be considered instead of the slower but more general constraint handler diving variable selection?

Definition at line 60 of file heur_fracdiving.c.

Referenced by SCIPincludeHeurFracdiving().

DEFAULT_RANDSEED

#define DEFAULT_RANDSEED   89

initial random seed

Definition at line 63 of file heur_fracdiving.c.

Referenced by SCIPincludeHeurFracdiving().

Function Documentation

SCIP_DECL_HEURCOPY()

static SCIP_DECL_HEURCOPY ( heurCopyFracdiving  )

static

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

Definition at line 82 of file heur_fracdiving.c.

SCIP_DECL_HEURFREE()

static SCIP_DECL_HEURFREE ( heurFreeFracdiving  )

static

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

Definition at line 96 of file heur_fracdiving.c.

SCIP_DECL_HEURINIT()

static SCIP_DECL_HEURINIT ( heurInitFracdiving  )

static

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

Definition at line 117 of file heur_fracdiving.c.

SCIP_DECL_HEUREXIT()

static SCIP_DECL_HEUREXIT ( heurExitFracdiving  )

static

deinitialization method of primal heuristic (called before transformed problem is freed)

Definition at line 137 of file heur_fracdiving.c.

SCIP_DECL_HEUREXEC()

static SCIP_DECL_HEUREXEC ( heurExecFracdiving  )

static

execution method of primal heuristic

Definition at line 158 of file heur_fracdiving.c.

SCIP_DECL_DIVESETGETSCORE()

static SCIP_DECL_DIVESETGETSCORE ( divesetGetScoreFracdiving  )

static

calculate score and preferred rounding direction for the candidate variable; the best candidate maximizes the score

Definition at line 182 of file heur_fracdiving.c.

References SCIP_OKAY, SCIP_PROBINGSCORE_PENALTYRATIO, SCIPdivesetGetRandnumgen(), SCIPgetObjNorm(), SCIPincludeHeurFracdiving(), SCIPisEQ(), SCIPisFeasPositive(), SCIPisPositive(), SCIPrandomGetInt(), SCIPvarGetObj(), SCIPvarIsBinary(), SCIPvarMayRoundDown(), and SCIPvarMayRoundUp().