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Detailed Description

LP diving heuristic that chooses fixings in direction of incumbent solutions.

Author
Tobias Achterberg

Definition in file heur_guideddiving.c.

#include "scip/heur_guideddiving.h"
#include "scip/heuristics.h"
#include "scip/pub_heur.h"
#include "scip/pub_message.h"
#include "scip/pub_sol.h"
#include "scip/pub_var.h"
#include "scip/scip_heur.h"
#include "scip/scip_lp.h"
#include "scip/scip_mem.h"
#include "scip/scip_numerics.h"
#include "scip/scip_prob.h"
#include "scip/scip_sol.h"
#include <string.h>

Go to the source code of this file.

Macros

#define HEUR_NAME   "guideddiving"
 
#define HEUR_DESC   "LP diving heuristic that chooses fixings in direction of incumbent solutions"
 
#define HEUR_DISPCHAR   SCIP_HEURDISPCHAR_DIVING
 
#define HEUR_PRIORITY   -1007000
 
#define HEUR_FREQ   10
 
#define HEUR_FREQOFS   7
 
#define HEUR_MAXDEPTH   -1
 
#define HEUR_TIMING   SCIP_HEURTIMING_AFTERLPPLUNGE
 
#define HEUR_USESSUBSCIP   FALSE
 
#define DIVESET_DIVETYPES   SCIP_DIVETYPE_INTEGRALITY
 
#define DIVESET_ISPUBLIC   TRUE
 
#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_BACKTRACK   TRUE
 
#define DEFAULT_LPRESOLVEDOMCHGQUOT   0.15
 
#define DEFAULT_LPSOLVEFREQ   0
 
#define DEFAULT_ONLYLPBRANCHCANDS   FALSE
 
#define DEFAULT_RANDSEED   127
 

Functions

static SCIP_DECL_HEURCOPY (heurCopyGuideddiving)
 
static assert (heur !=NULL)
 
 assert (strcmp(SCIPheurGetName(heur), HEUR_NAME)==0)
 
 assert (scip !=NULL)
 
 assert (heurdata !=NULL)
 
 SCIPfreeBlockMemory (scip, &heurdata)
 
 SCIPheurSetData (heur, NULL)
 
 SCIPcreateSol (scip, &heurdata->sol, heur))
 
 SCIPfreeSol (scip, &heurdata->sol))
 
 assert (result !=NULL)
 
 assert (SCIPhasCurrentNodeLP(scip))
 
 if (SCIPgetNSols(scip)==0)
 
static SCIP_DECL_DIVESETAVAILABLE (divesetAvailableGuideddiving)
 
SCIP_RETCODE SCIPincludeHeurGuideddiving (SCIP *scip)
 

Variables

 heurdata = SCIPheurGetData(heur)
 
return SCIP_OKAY
 
static SCIP_DIVESETdiveset
 
result = SCIP_DIDNOTRUN
 

Macro Definition Documentation

◆ HEUR_NAME

#define HEUR_NAME   "guideddiving"

Definition at line 47 of file heur_guideddiving.c.

◆ HEUR_DESC

#define HEUR_DESC   "LP diving heuristic that chooses fixings in direction of incumbent solutions"

Definition at line 48 of file heur_guideddiving.c.

◆ HEUR_DISPCHAR

#define HEUR_DISPCHAR   SCIP_HEURDISPCHAR_DIVING

Definition at line 49 of file heur_guideddiving.c.

◆ HEUR_PRIORITY

#define HEUR_PRIORITY   -1007000

Definition at line 50 of file heur_guideddiving.c.

◆ HEUR_FREQ

#define HEUR_FREQ   10

Definition at line 51 of file heur_guideddiving.c.

◆ HEUR_FREQOFS

#define HEUR_FREQOFS   7

Definition at line 52 of file heur_guideddiving.c.

◆ HEUR_MAXDEPTH

#define HEUR_MAXDEPTH   -1

Definition at line 53 of file heur_guideddiving.c.

◆ HEUR_TIMING

#define HEUR_TIMING   SCIP_HEURTIMING_AFTERLPPLUNGE

Definition at line 54 of file heur_guideddiving.c.

◆ HEUR_USESSUBSCIP

#define HEUR_USESSUBSCIP   FALSE

does the heuristic use a secondary SCIP instance?

Definition at line 55 of file heur_guideddiving.c.

◆ DIVESET_DIVETYPES

#define DIVESET_DIVETYPES   SCIP_DIVETYPE_INTEGRALITY

bit mask that represents all supported dive types

Definition at line 56 of file heur_guideddiving.c.

◆ DIVESET_ISPUBLIC

#define DIVESET_ISPUBLIC   TRUE

is this dive set publicly available (ie., can be used by other primal heuristics?)

Definition at line 57 of file heur_guideddiving.c.

◆ DEFAULT_MINRELDEPTH

#define DEFAULT_MINRELDEPTH   0.0

minimal relative depth to start diving

Definition at line 64 of file heur_guideddiving.c.

◆ DEFAULT_MAXRELDEPTH

#define DEFAULT_MAXRELDEPTH   1.0

maximal relative depth to start diving

Definition at line 65 of file heur_guideddiving.c.

◆ DEFAULT_MAXLPITERQUOT

#define DEFAULT_MAXLPITERQUOT   0.05

maximal fraction of diving LP iterations compared to node LP iterations

Definition at line 66 of file heur_guideddiving.c.

◆ DEFAULT_MAXLPITEROFS

#define DEFAULT_MAXLPITEROFS   1000

additional number of allowed LP iterations

Definition at line 67 of file heur_guideddiving.c.

◆ DEFAULT_MAXDIVEUBQUOT

#define DEFAULT_MAXDIVEUBQUOT   0.8

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

Definition at line 68 of file heur_guideddiving.c.

◆ DEFAULT_MAXDIVEAVGQUOT

#define DEFAULT_MAXDIVEAVGQUOT   0.0

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

Definition at line 70 of file heur_guideddiving.c.

◆ DEFAULT_BACKTRACK

#define DEFAULT_BACKTRACK   TRUE

use one level of backtracking if infeasibility is encountered?

Definition at line 72 of file heur_guideddiving.c.

◆ DEFAULT_LPRESOLVEDOMCHGQUOT

#define DEFAULT_LPRESOLVEDOMCHGQUOT   0.15

percentage of immediate domain changes during probing to trigger LP resolve

Definition at line 73 of file heur_guideddiving.c.

◆ DEFAULT_LPSOLVEFREQ

#define DEFAULT_LPSOLVEFREQ   0

LP solve frequency for diving heuristics

Definition at line 74 of file heur_guideddiving.c.

◆ 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 75 of file heur_guideddiving.c.

◆ DEFAULT_RANDSEED

#define DEFAULT_RANDSEED   127

initial seed for random number generation

Definition at line 77 of file heur_guideddiving.c.

Function Documentation

◆ SCIP_DECL_HEURCOPY()

static SCIP_DECL_HEURCOPY ( heurCopyGuideddiving )
static

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

Definition at line 95 of file heur_guideddiving.c.

References assert(), HEUR_NAME, NULL, SCIP_CALL, SCIP_OKAY, SCIPheurGetName(), and SCIPincludeHeurGuideddiving().

◆ assert() [1/6]

static assert ( heur ! = NULL)

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

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

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

References NULL.

◆ assert() [2/6]

assert ( strcmp(SCIPheurGetName(heur), HEUR_NAME) = =0)

References HEUR_NAME.

◆ assert() [3/6]

assert ( scip ! = NULL)

References NULL.

◆ assert() [4/6]

assert ( heurdata ! = NULL)

References heurdata, and NULL.

◆ SCIPfreeBlockMemory()

SCIPfreeBlockMemory ( scip ,
& heurdata )

References heurdata.

◆ SCIPheurSetData()

SCIPheurSetData ( heur ,
NULL  )

References NULL.

◆ SCIPcreateSol()

SCIPcreateSol ( scip ,
&heurdata-> sol,
heur  )

References heurdata, and SCIP_OKAY.

◆ SCIPfreeSol()

SCIPfreeSol ( scip ,
&heurdata-> sol )

References heurdata, and SCIP_OKAY.

◆ assert() [5/6]

assert ( result ! = NULL)

References NULL, and result.

◆ assert() [6/6]

assert ( SCIPhasCurrentNodeLP(scip) )

◆ if()

if ( SCIPgetNSols(scip) = = 0)

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

Definition at line 184 of file heur_guideddiving.c.

References diveset, heurdata, NULL, result, SCIP_DIVECONTEXT_SINGLE, and SCIP_OKAY.

◆ SCIP_DECL_DIVESETAVAILABLE()

static SCIP_DECL_DIVESETAVAILABLE ( divesetAvailableGuideddiving )
static

callback to check preconditions for diving, e.g., if an incumbent solution is available

Definition at line 275 of file heur_guideddiving.c.

References FALSE, SCIP_OKAY, SCIPgetBestSol(), SCIPgetNSols(), SCIPsolIsOriginal(), and TRUE.

Variable Documentation

◆ heurdata

heurdata = SCIPheurGetData(heur)

Definition at line 118 of file heur_guideddiving.c.

◆ SCIP_OKAY

return SCIP_OKAY

Definition at line 124 of file heur_guideddiving.c.

◆ diveset

SCIP_DIVESET* diveset
Initial value:
{
struct SCIP_HeurData SCIP_HEURDATA
Definition type_heur.h:77

execution method of primal heuristic

Definition at line 173 of file heur_guideddiving.c.

◆ result

* result = SCIP_DIDNOTRUN

Definition at line 181 of file heur_guideddiving.c.