Scippy

SCIP

Solving Constraint Integer Programs

heur_objpscostdiving.c File Reference

Detailed Description

LP diving heuristic that changes variable's objective value instead of bounds, using pseudo cost values as guide.

Author
Tobias Achterberg

Definition in file heur_objpscostdiving.c.

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

Go to the source code of this file.

Macros

#define HEUR_NAME   "objpscostdiving"
 
#define HEUR_DESC   "LP diving heuristic that changes variable's objective values instead of bounds, using pseudo costs as guide"
 
#define HEUR_DISPCHAR   'o'
 
#define HEUR_PRIORITY   -1004000
 
#define HEUR_FREQ   20
 
#define HEUR_FREQOFS   4
 
#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   0.01
 
#define DEFAULT_MAXLPITEROFS   1000
 
#define DEFAULT_MAXSOLS   -1
 
#define DEFAULT_DEPTHFAC   0.5
 
#define DEFAULT_DEPTHFACNOSOL   2.0
 
#define DEFAULT_RANDSEED   139
 
#define MINLPITER   10000
 

Functions

static void calcPscostQuot (SCIP *scip, SCIP_HEURDATA *heurdata, SCIP_VAR *var, SCIP_Real primsol, SCIP_Real frac, int rounddir, SCIP_Real *pscostquot, SCIP_Bool *roundup)
 
static SCIP_DECL_HEURCOPY (heurCopyObjpscostdiving)
 
static SCIP_DECL_HEURFREE (heurFreeObjpscostdiving)
 
static SCIP_DECL_HEURINIT (heurInitObjpscostdiving)
 
static SCIP_DECL_HEUREXIT (heurExitObjpscostdiving)
 
static SCIP_DECL_HEUREXEC (heurExecObjpscostdiving)
 
SCIP_RETCODE SCIPincludeHeurObjpscostdiving (SCIP *scip)
 

Macro Definition Documentation

◆ HEUR_NAME

◆ HEUR_DESC

#define HEUR_DESC   "LP diving heuristic that changes variable's objective values instead of bounds, using pseudo costs as guide"

Definition at line 30 of file heur_objpscostdiving.c.

Referenced by SCIPincludeHeurObjpscostdiving().

◆ HEUR_DISPCHAR

#define HEUR_DISPCHAR   'o'

Definition at line 31 of file heur_objpscostdiving.c.

Referenced by SCIPincludeHeurObjpscostdiving().

◆ HEUR_PRIORITY

#define HEUR_PRIORITY   -1004000

Definition at line 32 of file heur_objpscostdiving.c.

Referenced by SCIPincludeHeurObjpscostdiving().

◆ HEUR_FREQ

#define HEUR_FREQ   20

Definition at line 33 of file heur_objpscostdiving.c.

Referenced by SCIPincludeHeurObjpscostdiving().

◆ HEUR_FREQOFS

#define HEUR_FREQOFS   4

Definition at line 34 of file heur_objpscostdiving.c.

Referenced by SCIPincludeHeurObjpscostdiving().

◆ HEUR_MAXDEPTH

#define HEUR_MAXDEPTH   -1

Definition at line 35 of file heur_objpscostdiving.c.

Referenced by SCIPincludeHeurObjpscostdiving().

◆ HEUR_TIMING

#define HEUR_TIMING   SCIP_HEURTIMING_AFTERLPPLUNGE

Definition at line 36 of file heur_objpscostdiving.c.

Referenced by SCIPincludeHeurObjpscostdiving().

◆ HEUR_USESSUBSCIP

#define HEUR_USESSUBSCIP   FALSE

does the heuristic use a secondary SCIP instance?

Definition at line 37 of file heur_objpscostdiving.c.

Referenced by SCIPincludeHeurObjpscostdiving().

◆ DEFAULT_MINRELDEPTH

#define DEFAULT_MINRELDEPTH   0.0

minimal relative depth to start diving

Definition at line 44 of file heur_objpscostdiving.c.

Referenced by SCIPincludeHeurObjpscostdiving().

◆ DEFAULT_MAXRELDEPTH

#define DEFAULT_MAXRELDEPTH   1.0

maximal relative depth to start diving

Definition at line 45 of file heur_objpscostdiving.c.

Referenced by SCIPincludeHeurObjpscostdiving().

◆ DEFAULT_MAXLPITERQUOT

#define DEFAULT_MAXLPITERQUOT   0.01

maximal fraction of diving LP iterations compared to total iteration number

Definition at line 46 of file heur_objpscostdiving.c.

Referenced by SCIPincludeHeurObjpscostdiving().

◆ DEFAULT_MAXLPITEROFS

#define DEFAULT_MAXLPITEROFS   1000

additional number of allowed LP iterations

Definition at line 47 of file heur_objpscostdiving.c.

Referenced by SCIPincludeHeurObjpscostdiving().

◆ DEFAULT_MAXSOLS

#define DEFAULT_MAXSOLS   -1

total number of feasible solutions found up to which heuristic is called (-1: no limit)

Definition at line 48 of file heur_objpscostdiving.c.

Referenced by SCIPincludeHeurObjpscostdiving().

◆ DEFAULT_DEPTHFAC

#define DEFAULT_DEPTHFAC   0.5

maximal diving depth: number of binary/integer variables times depthfac

Definition at line 51 of file heur_objpscostdiving.c.

Referenced by SCIPincludeHeurObjpscostdiving().

◆ DEFAULT_DEPTHFACNOSOL

#define DEFAULT_DEPTHFACNOSOL   2.0

maximal diving depth factor if no feasible solution was found yet

Definition at line 52 of file heur_objpscostdiving.c.

Referenced by SCIPincludeHeurObjpscostdiving().

◆ DEFAULT_RANDSEED

#define DEFAULT_RANDSEED   139

initial random seed

Definition at line 53 of file heur_objpscostdiving.c.

Referenced by SCIP_DECL_HEURINIT().

◆ MINLPITER

#define MINLPITER   10000

minimal number of LP iterations allowed in each LP solving call

Definition at line 55 of file heur_objpscostdiving.c.

Referenced by SCIP_DECL_HEUREXEC().

Function Documentation

◆ calcPscostQuot()

static void calcPscostQuot ( SCIP scip,
SCIP_HEURDATA heurdata,
SCIP_VAR var,
SCIP_Real  primsol,
SCIP_Real  frac,
int  rounddir,
SCIP_Real pscostquot,
SCIP_Bool roundup 
)
static
Parameters
scipSCIP data structure
heurdataheuristic data structure
varproblem variable
primsolprimal solution of variable
fracfractionality of variable
rounddir-1: round down, +1: round up, 0: select due to pseudo cost values
pscostquotpointer to store pseudo cost quotient
rounduppointer to store whether the variable should be rounded up

Definition at line 81 of file heur_objpscostdiving.c.

References FALSE, MAX, SCIP_DECL_HEURCOPY(), SCIP_Real, SCIPgetVarPseudocostVal(), SCIPisEQ(), SCIPisGT(), SCIPisLT(), SCIPrandomGetInt(), SCIPvarGetRootSol(), SCIPvarIsBinary(), sqrt(), and TRUE.

Referenced by SCIP_DECL_HEUREXEC().

◆ SCIP_DECL_HEURCOPY()

static SCIP_DECL_HEURCOPY ( heurCopyObjpscostdiving  )
static

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

Definition at line 151 of file heur_objpscostdiving.c.

References HEUR_NAME, SCIP_CALL, SCIP_DECL_HEURFREE(), SCIP_OKAY, SCIPheurGetName(), and SCIPincludeHeurObjpscostdiving().

Referenced by calcPscostQuot().

◆ SCIP_DECL_HEURFREE()

static SCIP_DECL_HEURFREE ( heurFreeObjpscostdiving  )
static

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

Definition at line 165 of file heur_objpscostdiving.c.

References HEUR_NAME, SCIP_DECL_HEURINIT(), SCIP_OKAY, SCIPfreeBlockMemory, SCIPheurGetData(), SCIPheurGetName(), and SCIPheurSetData().

Referenced by SCIP_DECL_HEURCOPY().

◆ SCIP_DECL_HEURINIT()

static SCIP_DECL_HEURINIT ( heurInitObjpscostdiving  )
static

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

Definition at line 185 of file heur_objpscostdiving.c.

References DEFAULT_RANDSEED, HEUR_NAME, SCIP_CALL, SCIP_DECL_HEUREXIT(), SCIP_OKAY, SCIPcreateRandom(), SCIPcreateSol(), SCIPheurGetData(), and SCIPheurGetName().

Referenced by SCIP_DECL_HEURFREE().

◆ SCIP_DECL_HEUREXIT()

static SCIP_DECL_HEUREXIT ( heurExitObjpscostdiving  )
static

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

Definition at line 212 of file heur_objpscostdiving.c.

References HEUR_NAME, SCIP_CALL, SCIP_DECL_HEUREXEC(), SCIP_OKAY, SCIPfreeRandom(), SCIPfreeSol(), SCIPheurGetData(), and SCIPheurGetName().

Referenced by SCIP_DECL_HEURINIT().

◆ SCIP_DECL_HEUREXEC()