heur_coefdiving.c File Reference

Detailed Description

LP diving heuristic that chooses fixings w.r.t. the matrix coefficients.

Author

Tobias Achterberg

Marc Pfetsch

Indicator constraints are taken into account if present.

Definition in file heur_coefdiving.c.

#include <assert.h>
#include <string.h>
#include "scip/heur_coefdiving.h"
#include "scip/cons_indicator.h"

Go to the source code of this file.

Macros
#define	HEUR_NAME   "coefdiving"
#define	HEUR_DESC   "LP diving heuristic that chooses fixings w.r.t. the matrix coefficients"
#define	HEUR_DISPCHAR   'c'
#define	HEUR_PRIORITY   -1001000
#define	HEUR_FREQ   10
#define	HEUR_FREQOFS   1
#define	HEUR_MAXDEPTH   -1
#define	HEUR_TIMING   SCIP_HEURTIMING_AFTERLPPLUNGE
#define	HEUR_USESSUBSCIP   FALSE
#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	MINLPITER   10000

Functions
static SCIP_RETCODE	getIndCandVars (SCIP *scip, SCIP_CONS **indconss, int nindconss, SCIP_VAR **indcands, SCIP_Real *indcandssol, SCIP_Real *indcandfrac, int *nindcands)
static SCIP_RETCODE	getBestCandidate (SCIP *scip, SCIP_VAR **cands, SCIP_Real *candssol, SCIP_Real *candsfrac, int ncands, int *bestcand, int *bestnviolrows, SCIP_Real *bestcandsol, SCIP_Real *bestcandfrac, SCIP_Bool *bestcandmayrounddown, SCIP_Bool *bestcandmayroundup, SCIP_Bool *bestcandroundup)
static	SCIP_DECL_HEURCOPY (heurCopyCoefdiving)
static	SCIP_DECL_HEURFREE (heurFreeCoefdiving)
static	SCIP_DECL_HEURINIT (heurInitCoefdiving)
static	SCIP_DECL_HEUREXIT (heurExitCoefdiving)
static	SCIP_DECL_HEUREXEC (heurExecCoefdiving)
SCIP_RETCODE	SCIPincludeHeurCoefdiving (SCIP *scip)

Macro Definition Documentation

#define HEUR_NAME   "coefdiving"

Definition at line 33 of file heur_coefdiving.c.

Referenced by SCIPincludeHeurCoefdiving().

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

Definition at line 34 of file heur_coefdiving.c.

Referenced by SCIPincludeHeurCoefdiving().

#define HEUR_DISPCHAR   'c'

Definition at line 35 of file heur_coefdiving.c.

Referenced by SCIPincludeHeurCoefdiving().

#define HEUR_PRIORITY   -1001000

Definition at line 36 of file heur_coefdiving.c.

Referenced by SCIPincludeHeurCoefdiving().

#define HEUR_FREQ   10

Definition at line 37 of file heur_coefdiving.c.

Referenced by SCIPincludeHeurCoefdiving().

#define HEUR_FREQOFS   1

Definition at line 38 of file heur_coefdiving.c.

Referenced by SCIPincludeHeurCoefdiving().

#define HEUR_MAXDEPTH   -1

Definition at line 39 of file heur_coefdiving.c.

Referenced by SCIPincludeHeurCoefdiving().

#define HEUR_TIMING   SCIP_HEURTIMING_AFTERLPPLUNGE

Definition at line 40 of file heur_coefdiving.c.

Referenced by SCIPincludeHeurCoefdiving().

#define HEUR_USESSUBSCIP   FALSE

does the heuristic use a secondary SCIP instance?

Definition at line 41 of file heur_coefdiving.c.

Referenced by SCIPincludeHeurCoefdiving().

#define DEFAULT_MINRELDEPTH   0.0

minimal relative depth to start diving

Definition at line 48 of file heur_coefdiving.c.

Referenced by SCIPincludeHeurCoefdiving().

#define DEFAULT_MAXRELDEPTH   1.0

maximal relative depth to start diving

Definition at line 49 of file heur_coefdiving.c.

Referenced by SCIPincludeHeurCoefdiving().

#define DEFAULT_MAXLPITERQUOT   0.05

maximal fraction of diving LP iterations compared to node LP iterations

Definition at line 50 of file heur_coefdiving.c.

Referenced by SCIPincludeHeurCoefdiving().

#define DEFAULT_MAXLPITEROFS   1000

additional number of allowed LP iterations

Definition at line 51 of file heur_coefdiving.c.

Referenced by SCIPincludeHeurCoefdiving().

#define DEFAULT_MAXDIVEUBQUOT   0.8

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

Definition at line 52 of file heur_coefdiving.c.

Referenced by SCIPincludeHeurCoefdiving().

#define DEFAULT_MAXDIVEAVGQUOT   0.0

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

Definition at line 55 of file heur_coefdiving.c.

Referenced by SCIPincludeHeurCoefdiving().

#define DEFAULT_MAXDIVEUBQUOTNOSOL   0.1

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

Definition at line 58 of file heur_coefdiving.c.

Referenced by SCIPincludeHeurCoefdiving().

#define DEFAULT_MAXDIVEAVGQUOTNOSOL   0.0

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

Definition at line 59 of file heur_coefdiving.c.

Referenced by SCIPincludeHeurCoefdiving().

#define DEFAULT_BACKTRACK   TRUE

use one level of backtracking if infeasibility is encountered?

Definition at line 60 of file heur_coefdiving.c.

Referenced by SCIPincludeHeurCoefdiving().

#define MINLPITER   10000

minimal number of LP iterations allowed in each LP solving call

Definition at line 62 of file heur_coefdiving.c.

Function Documentation

static SCIP_RETCODE getIndCandVars ( SCIP *  scip, SCIP_CONS **  indconss, int  nindconss, SCIP_VAR **  indcands, SCIP_Real *  indcandssol, SCIP_Real *  indcandfrac, int *  nindcands  )

static

get indicator candidate variables

Parameters

scip	SCIP data structure
indconss	indicator constraints
nindconss	number of indicator constraints
indcands	indicator candidate variables
indcandssol	solution values of candidates
indcandfrac	fractionalities of candidates
nindcands	number of candidates

Definition at line 93 of file heur_coefdiving.c.

References NULL, SCIP_OKAY, SCIP_Real, SCIPfrac(), SCIPgetBinaryVarIndicator(), SCIPgetSolVal(), SCIPisFeasIntegral(), and SCIPisViolatedIndicator().

static SCIP_RETCODE getBestCandidate ( SCIP *  scip, SCIP_VAR **  cands, SCIP_Real *  candssol, SCIP_Real *  candsfrac, int  ncands, int *  bestcand, int *  bestnviolrows, SCIP_Real *  bestcandsol, SCIP_Real *  bestcandfrac, SCIP_Bool *  bestcandmayrounddown, SCIP_Bool *  bestcandmayroundup, SCIP_Bool *  bestcandroundup  )

static

choose best candidate variable

Parameters

scip	SCIP data structure
cands	candidate variables
candssol	solution values of candidates
candsfrac	fractional solution values of candidates
ncands	number of candidates
bestcand	bestcandidate
bestnviolrows	number of violated rows for best candidate
bestcandsol	solution of best candidate
bestcandfrac	fractionality of best candidate
bestcandmayrounddown	whether best candidate may be rounded down
bestcandmayroundup	whether best candidate may be rounded down
bestcandroundup	whether the best candidate should be rounded up

Definition at line 139 of file heur_coefdiving.c.

References FALSE, NULL, SCIP_Bool, SCIP_INVALID, SCIP_OKAY, SCIP_Real, SCIPvarGetNLocksDown(), SCIPvarGetNLocksUp(), SCIPvarIsBinary(), SCIPvarMayRoundDown(), and SCIPvarMayRoundUp().

static SCIP_DECL_HEURCOPY ( heurCopyCoefdiving  )

static

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

Definition at line 275 of file heur_coefdiving.c.

static SCIP_DECL_HEURFREE ( heurFreeCoefdiving  )

static

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

Definition at line 289 of file heur_coefdiving.c.

static SCIP_DECL_HEURINIT ( heurInitCoefdiving  )

static

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

Definition at line 309 of file heur_coefdiving.c.

static SCIP_DECL_HEUREXIT ( heurExitCoefdiving  )

static

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

Definition at line 336 of file heur_coefdiving.c.

static SCIP_DECL_HEUREXEC ( heurExecCoefdiving  )

static

execution method of primal heuristic

Definition at line 356 of file heur_coefdiving.c.

SCIP_RETCODE SCIPincludeHeurCoefdiving

(

SCIP *

scip

)

creates the coefdiving heuristic and includes it in SCIP

Parameters

scip	SCIP data structure

Definition at line 828 of file heur_coefdiving.c.

References DEFAULT_BACKTRACK, DEFAULT_MAXDIVEAVGQUOT, DEFAULT_MAXDIVEAVGQUOTNOSOL, DEFAULT_MAXDIVEUBQUOT, DEFAULT_MAXDIVEUBQUOTNOSOL, DEFAULT_MAXLPITEROFS, DEFAULT_MAXLPITERQUOT, DEFAULT_MAXRELDEPTH, DEFAULT_MINRELDEPTH, FALSE, HEUR_DESC, HEUR_DISPCHAR, HEUR_FREQ, HEUR_FREQOFS, HEUR_MAXDEPTH, HEUR_NAME, HEUR_PRIORITY, HEUR_TIMING, HEUR_USESSUBSCIP, NULL, SCIP_CALL, SCIP_OKAY, SCIP_REAL_MAX, SCIPaddBoolParam(), SCIPaddIntParam(), SCIPaddRealParam(), SCIPallocMemory, SCIPincludeHeurBasic(), SCIPsetHeurCopy(), SCIPsetHeurExit(), SCIPsetHeurFree(), SCIPsetHeurInit(), and TRUE.

Referenced by SCIPincludeDefaultPlugins().