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Data Structures | Macros | Functions
heur_gcgcoefdiving.c File Reference

Detailed Description

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

Author
Tobias Achterberg
Christian Puchert

Definition in file heur_gcgcoefdiving.c.

#include <assert.h>
#include <string.h>
#include "heur_gcgcoefdiving.h"
#include "heur_origdiving.h"
#include "gcg.h"

Go to the source code of this file.

Data Structures

struct  GCG_DivingData
 

Macros

#define HEUR_NAME   "gcgcoefdiving"
 
#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 DEFAULT_USEMASTERLOCKS   FALSE
 

Functions

static SCIP_Bool areVarsInSameBlock (SCIP_VAR *origvar, SCIP_VAR *mastervar)
 
static SCIP_RETCODE getNLocksDown (SCIP *scip, SCIP_VAR *var, int *nlocksdown)
 
static SCIP_RETCODE getNLocksUp (SCIP *scip, SCIP_VAR *var, int *nlocksup)
 
static GCG_DECL_DIVINGFREE (heurFreeGcgcoefdiving)
 
static GCG_DECL_DIVINGSELECTVAR (heurSelectVarGcgcoefdiving)
 
SCIP_RETCODE GCGincludeHeurGcgcoefdiving (SCIP *scip)
 

Macro Definition Documentation

◆ HEUR_NAME

#define HEUR_NAME   "gcgcoefdiving"

Definition at line 44 of file heur_gcgcoefdiving.c.

◆ HEUR_DESC

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

Definition at line 45 of file heur_gcgcoefdiving.c.

◆ HEUR_DISPCHAR

#define HEUR_DISPCHAR   'c'

Definition at line 46 of file heur_gcgcoefdiving.c.

◆ HEUR_PRIORITY

#define HEUR_PRIORITY   -1001000

Definition at line 47 of file heur_gcgcoefdiving.c.

◆ HEUR_FREQ

#define HEUR_FREQ   10

Definition at line 48 of file heur_gcgcoefdiving.c.

◆ HEUR_FREQOFS

#define HEUR_FREQOFS   1

Definition at line 49 of file heur_gcgcoefdiving.c.

◆ HEUR_MAXDEPTH

#define HEUR_MAXDEPTH   -1

Definition at line 50 of file heur_gcgcoefdiving.c.

◆ DEFAULT_USEMASTERLOCKS

#define DEFAULT_USEMASTERLOCKS   FALSE

calculate the number of locks w.r.t. the master LP?

Definition at line 57 of file heur_gcgcoefdiving.c.

Function Documentation

◆ areVarsInSameBlock()

static SCIP_Bool areVarsInSameBlock ( SCIP_VAR *  origvar,
SCIP_VAR *  mastervar 
)
static

check whether an original variable and a master variable belong to the same block

Parameters
origvaroriginal variable
mastervarmaster variable

Definition at line 73 of file heur_gcgcoefdiving.c.

References GCGisLinkingVarInBlock(), GCGoriginalVarGetMastervars(), GCGoriginalVarGetNMastervars(), GCGoriginalVarIsLinking(), and GCGvarGetBlock().

Referenced by getNLocksDown(), and getNLocksUp().

◆ getNLocksDown()

static SCIP_RETCODE getNLocksDown ( SCIP *  scip,
SCIP_VAR *  var,
int *  nlocksdown 
)
static

get the number of down-locks for an original variable w.r.t. the master problem

Parameters
scipSCIP data structure
varoriginal variable to get locks for
nlocksdownpointer to store number of down-locks

Definition at line 128 of file heur_gcgcoefdiving.c.

References areVarsInSameBlock(), GCGgetMasterprob(), GCGoriginalVarGetMastervals(), GCGoriginalVarGetMastervars(), and GCGoriginalVarGetNMastervars().

Referenced by GCG_DECL_DIVINGSELECTVAR().

◆ getNLocksUp()

static SCIP_RETCODE getNLocksUp ( SCIP *  scip,
SCIP_VAR *  var,
int *  nlocksup 
)
static

get the number of up-locks for an original variable w.r.t. the master problem

Parameters
scipSCIP data structure
varoriginal variable to get locks for
nlocksuppointer to store number of up-locks

Definition at line 189 of file heur_gcgcoefdiving.c.

References areVarsInSameBlock(), GCGgetMasterprob(), GCGoriginalVarGetMastervals(), GCGoriginalVarGetMastervars(), and GCGoriginalVarGetNMastervars().

Referenced by GCG_DECL_DIVINGSELECTVAR().

◆ GCG_DECL_DIVINGFREE()

static GCG_DECL_DIVINGFREE ( heurFreeGcgcoefdiving  )
static

destructor of diving heuristic to free user data (called when GCG is exiting)

Definition at line 255 of file heur_gcgcoefdiving.c.

References GCGheurGetDivingDataOrig(), and GCGheurSetDivingDataOrig().

◆ GCG_DECL_DIVINGSELECTVAR()

static GCG_DECL_DIVINGSELECTVAR ( heurSelectVarGcgcoefdiving  )
static

variable selection method of diving heuristic; finds best candidate variable w.r.t. locking numbers:

  • prefer variables that may not be rounded without destroying LP feasibility:
    • of these variables, round variable with least number of locks in corresponding direction
  • if all remaining fractional variables may be rounded without destroying LP feasibility:
    • round variable with least number of locks in opposite of its feasible rounding direction
  • binary variables are preferred

Definition at line 281 of file heur_gcgcoefdiving.c.

References GCGheurGetDivingDataOrig(), getNLocksDown(), getNLocksUp(), and GCG_DivingData::usemasterlocks.

◆ GCGincludeHeurGcgcoefdiving()

SCIP_RETCODE GCGincludeHeurGcgcoefdiving ( SCIP *  scip)

creates the gcgcoefdiving heuristic and includes it in GCG

Parameters
scipSCIP data structure

Definition at line 445 of file heur_gcgcoefdiving.c.

References DEFAULT_USEMASTERLOCKS, GCGincludeDivingHeurOrig(), HEUR_DESC, HEUR_DISPCHAR, HEUR_FREQ, HEUR_FREQOFS, HEUR_MAXDEPTH, HEUR_NAME, HEUR_PRIORITY, and GCG_DivingData::usemasterlocks.

Referenced by SCIPincludeGcgPlugins().