Scippy

SCIP

Solving Constraint Integer Programs

Macros | Functions
heur_pscostdiving.c File Reference

Detailed Description

LP diving heuristic that chooses fixings w.r.t. the pseudo cost values.

Author
Tobias Achterberg

Definition in file heur_pscostdiving.c.

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

Go to the source code of this file.

Macros

#define HEUR_NAME   "pscostdiving"
 
#define HEUR_DESC   "LP diving heuristic that chooses fixings w.r.t. the pseudo cost values"
 
#define HEUR_DISPCHAR   'p'
 
#define HEUR_PRIORITY   -1002000
 
#define HEUR_FREQ   10
 
#define HEUR_FREQOFS   2
 
#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 void calcPscostQuot (SCIP *scip, SCIP_VAR *var, SCIP_Real primsol, SCIP_Real frac, int rounddir, SCIP_Real *pscostquot, SCIP_Bool *roundup)
 
static SCIP_DECL_HEURCOPY (heurCopyPscostdiving)
 
static SCIP_DECL_HEURFREE (heurFreePscostdiving)
 
static SCIP_DECL_HEURINIT (heurInitPscostdiving)
 
static SCIP_DECL_HEUREXIT (heurExitPscostdiving)
 
static SCIP_DECL_HEUREXEC (heurExecPscostdiving)
 
SCIP_RETCODE SCIPincludeHeurPscostdiving (SCIP *scip)
 

Macro Definition Documentation

#define HEUR_NAME   "pscostdiving"

Definition at line 29 of file heur_pscostdiving.c.

Referenced by SCIPincludeHeurPscostdiving().

#define HEUR_DESC   "LP diving heuristic that chooses fixings w.r.t. the pseudo cost values"

Definition at line 30 of file heur_pscostdiving.c.

Referenced by SCIPincludeHeurPscostdiving().

#define HEUR_DISPCHAR   'p'

Definition at line 31 of file heur_pscostdiving.c.

Referenced by SCIPincludeHeurPscostdiving().

#define HEUR_PRIORITY   -1002000

Definition at line 32 of file heur_pscostdiving.c.

Referenced by SCIPincludeHeurPscostdiving().

#define HEUR_FREQ   10

Definition at line 33 of file heur_pscostdiving.c.

Referenced by SCIPincludeHeurPscostdiving().

#define HEUR_FREQOFS   2

Definition at line 34 of file heur_pscostdiving.c.

Referenced by SCIPincludeHeurPscostdiving().

#define HEUR_MAXDEPTH   -1

Definition at line 35 of file heur_pscostdiving.c.

Referenced by SCIPincludeHeurPscostdiving().

#define HEUR_TIMING   SCIP_HEURTIMING_AFTERLPPLUNGE

Definition at line 36 of file heur_pscostdiving.c.

Referenced by SCIPincludeHeurPscostdiving().

#define HEUR_USESSUBSCIP   FALSE

does the heuristic use a secondary SCIP instance?

Definition at line 37 of file heur_pscostdiving.c.

Referenced by SCIPincludeHeurPscostdiving().

#define DEFAULT_MINRELDEPTH   0.0

minimal relative depth to start diving

Definition at line 44 of file heur_pscostdiving.c.

Referenced by SCIPincludeHeurPscostdiving().

#define DEFAULT_MAXRELDEPTH   1.0

maximal relative depth to start diving

Definition at line 45 of file heur_pscostdiving.c.

Referenced by SCIPincludeHeurPscostdiving().

#define DEFAULT_MAXLPITERQUOT   0.05

maximal fraction of diving LP iterations compared to node LP iterations

Definition at line 46 of file heur_pscostdiving.c.

Referenced by SCIPincludeHeurPscostdiving().

#define DEFAULT_MAXLPITEROFS   1000

additional number of allowed LP iterations

Definition at line 47 of file heur_pscostdiving.c.

Referenced by SCIPincludeHeurPscostdiving().

#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_pscostdiving.c.

Referenced by SCIPincludeHeurPscostdiving().

#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_pscostdiving.c.

Referenced by SCIPincludeHeurPscostdiving().

#define DEFAULT_MAXDIVEUBQUOTNOSOL   0.1

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

Definition at line 54 of file heur_pscostdiving.c.

Referenced by SCIPincludeHeurPscostdiving().

#define DEFAULT_MAXDIVEAVGQUOTNOSOL   0.0

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

Definition at line 55 of file heur_pscostdiving.c.

Referenced by SCIPincludeHeurPscostdiving().

#define DEFAULT_BACKTRACK   TRUE

use one level of backtracking if infeasibility is encountered?

Definition at line 56 of file heur_pscostdiving.c.

Referenced by SCIPincludeHeurPscostdiving().

#define MINLPITER   10000

minimal number of LP iterations allowed in each LP solving call

Definition at line 58 of file heur_pscostdiving.c.

Function Documentation

static void calcPscostQuot ( SCIP *  scip,
SCIP_VAR *  var,
SCIP_Real  primsol,
SCIP_Real  frac,
int  rounddir,
SCIP_Real *  pscostquot,
SCIP_Bool *  roundup 
)
static

calculates the pseudocost score for a given variable w.r.t. a given solution value and a given rounding direction

Parameters
scipSCIP 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 87 of file heur_pscostdiving.c.

References FALSE, MAX, MIN, NULL, SCIP_Real, SCIPfeasFloor(), SCIPgetVarPseudocostVal(), SCIPisEQ(), SCIPvarGetRootSol(), SCIPvarIsBinary(), sqrt(), and TRUE.

static SCIP_DECL_HEURCOPY ( heurCopyPscostdiving  )
static

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

Definition at line 149 of file heur_pscostdiving.c.

static SCIP_DECL_HEURFREE ( heurFreePscostdiving  )
static

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

Definition at line 163 of file heur_pscostdiving.c.

static SCIP_DECL_HEURINIT ( heurInitPscostdiving  )
static

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

Definition at line 183 of file heur_pscostdiving.c.

static SCIP_DECL_HEUREXIT ( heurExitPscostdiving  )
static

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

Definition at line 207 of file heur_pscostdiving.c.

static SCIP_DECL_HEUREXEC ( heurExecPscostdiving  )
static

execution method of primal heuristic

Definition at line 227 of file heur_pscostdiving.c.

SCIP_RETCODE SCIPincludeHeurPscostdiving ( SCIP *  scip)

creates the pscostdiving heuristic and includes it in SCIP

Parameters
scipSCIP data structure

Definition at line 655 of file heur_pscostdiving.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().