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Detailed Description

LP diving heuristic that chooses fixings w.r.t. conflict locks.

Author
Jakob Witzig

Definition in file heur_conflictdiving.c.

#include "scip/heur_conflictdiving.h"
#include "scip/heuristics.h"
#include "scip/pub_heur.h"
#include "scip/pub_message.h"
#include "scip/pub_misc.h"
#include "scip/pub_var.h"
#include "scip/scip_heur.h"
#include "scip/scip_mem.h"
#include "scip/scip_numerics.h"
#include "scip/scip_param.h"
#include "scip/scip_sol.h"
#include "scip/scip_solvingstats.h"
#include <string.h>

Go to the source code of this file.

Macros

#define HEUR_NAME   "conflictdiving"
 
#define HEUR_DESC   "LP diving heuristic that chooses fixings w.r.t. conflict locks"
 
#define HEUR_DISPCHAR   SCIP_HEURDISPCHAR_DIVING
 
#define HEUR_PRIORITY   -1000100
 
#define HEUR_FREQ   10
 
#define HEUR_FREQOFS   0
 
#define HEUR_MAXDEPTH   -1
 
#define HEUR_TIMING   SCIP_HEURTIMING_AFTERLPPLUNGE
 
#define HEUR_USESSUBSCIP   FALSE
 
#define DIVESET_DIVETYPES   SCIP_DIVETYPE_INTEGRALITY | SCIP_DIVETYPE_SOS1VARIABLE
 
#define DIVESET_ISPUBLIC   FALSE
 
#define DEFAULT_RANDSEED   151
 
#define DEFAULT_MINRELDEPTH   0.0
 
#define DEFAULT_MAXRELDEPTH   1.0
 
#define DEFAULT_MAXLPITERQUOT   0.15
 
#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 DEFAULT_LPRESOLVEDOMCHGQUOT   0.1
 
#define DEFAULT_LPSOLVEFREQ   0
 
#define DEFAULT_ONLYLPBRANCHCANDS   FALSE
 
#define DEFAULT_LOCKWEIGHT   0.75
 
#define DEFAULT_LIKECOEF   FALSE
 
#define DEFAULT_MAXVIOL   TRUE
 
#define DEFAULT_MINCONFLICTLOCKS   5
 
#define MIN_RAND   1e-06
 
#define MAX_RAND   1e-05
 
#define divesetAvailableConflictdiving   NULL
 

Functions

static SCIP_DECL_HEURCOPY (heurCopyConflictdiving)
 
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 (SCIPheurGetNDivesets(heur) > 0)
 
 assert (SCIPheurGetDivesets(heur) !=NULL)
 
 assert (diveset !=NULL)
 
 if (SCIPgetNConflictConssFound(scip)==0)
 
static SCIP_RETCODE getScore (SCIP *scip, SCIP_HEURDATA *heurdata, SCIP_RANDNUMGEN *rng, SCIP_DIVETYPE divetype, SCIP_VAR *cand, SCIP_Real candsol, SCIP_Real candsfrac, SCIP_Real *score, SCIP_Bool *roundup)
 
static SCIP_DECL_DIVESETGETSCORE (divesetGetScoreConflictdiving)
 
SCIP_RETCODE SCIPincludeHeurConflictdiving (SCIP *scip)
 

Variables

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

Macro Definition Documentation

◆ HEUR_NAME

#define HEUR_NAME   "conflictdiving"

Definition at line 47 of file heur_conflictdiving.c.

◆ HEUR_DESC

#define HEUR_DESC   "LP diving heuristic that chooses fixings w.r.t. conflict locks"

Definition at line 48 of file heur_conflictdiving.c.

◆ HEUR_DISPCHAR

#define HEUR_DISPCHAR   SCIP_HEURDISPCHAR_DIVING

Definition at line 49 of file heur_conflictdiving.c.

◆ HEUR_PRIORITY

#define HEUR_PRIORITY   -1000100

Definition at line 50 of file heur_conflictdiving.c.

◆ HEUR_FREQ

#define HEUR_FREQ   10

Definition at line 51 of file heur_conflictdiving.c.

◆ HEUR_FREQOFS

#define HEUR_FREQOFS   0

Definition at line 52 of file heur_conflictdiving.c.

◆ HEUR_MAXDEPTH

#define HEUR_MAXDEPTH   -1

Definition at line 53 of file heur_conflictdiving.c.

◆ HEUR_TIMING

#define HEUR_TIMING   SCIP_HEURTIMING_AFTERLPPLUNGE

Definition at line 54 of file heur_conflictdiving.c.

◆ HEUR_USESSUBSCIP

#define HEUR_USESSUBSCIP   FALSE

does the heuristic use a secondary SCIP instance?

Definition at line 55 of file heur_conflictdiving.c.

◆ DIVESET_DIVETYPES

#define DIVESET_DIVETYPES   SCIP_DIVETYPE_INTEGRALITY | SCIP_DIVETYPE_SOS1VARIABLE

bit mask that represents all supported dive types

Definition at line 56 of file heur_conflictdiving.c.

◆ DIVESET_ISPUBLIC

#define DIVESET_ISPUBLIC   FALSE

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

Definition at line 57 of file heur_conflictdiving.c.

◆ DEFAULT_RANDSEED

#define DEFAULT_RANDSEED   151

default random seed

Definition at line 58 of file heur_conflictdiving.c.

◆ DEFAULT_MINRELDEPTH

#define DEFAULT_MINRELDEPTH   0.0

minimal relative depth to start diving

Definition at line 64 of file heur_conflictdiving.c.

◆ DEFAULT_MAXRELDEPTH

#define DEFAULT_MAXRELDEPTH   1.0

maximal relative depth to start diving

Definition at line 65 of file heur_conflictdiving.c.

◆ DEFAULT_MAXLPITERQUOT

#define DEFAULT_MAXLPITERQUOT   0.15

maximal fraction of diving LP iterations compared to node LP iterations

Definition at line 66 of file heur_conflictdiving.c.

◆ DEFAULT_MAXLPITEROFS

#define DEFAULT_MAXLPITEROFS   1000

additional number of allowed LP iterations

Definition at line 67 of file heur_conflictdiving.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_conflictdiving.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_conflictdiving.c.

◆ DEFAULT_MAXDIVEUBQUOTNOSOL

#define DEFAULT_MAXDIVEUBQUOTNOSOL   0.1

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

Definition at line 72 of file heur_conflictdiving.c.

◆ DEFAULT_MAXDIVEAVGQUOTNOSOL

#define DEFAULT_MAXDIVEAVGQUOTNOSOL   0.0

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

Definition at line 73 of file heur_conflictdiving.c.

◆ DEFAULT_BACKTRACK

#define DEFAULT_BACKTRACK   TRUE

use one level of backtracking if infeasibility is encountered?

Definition at line 74 of file heur_conflictdiving.c.

◆ DEFAULT_LPRESOLVEDOMCHGQUOT

#define DEFAULT_LPRESOLVEDOMCHGQUOT   0.1

percentage of immediate domain changes during probing to trigger LP resolve

Definition at line 75 of file heur_conflictdiving.c.

◆ DEFAULT_LPSOLVEFREQ

#define DEFAULT_LPSOLVEFREQ   0

LP solve frequency for diving heuristics

Definition at line 76 of file heur_conflictdiving.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 77 of file heur_conflictdiving.c.

◆ DEFAULT_LOCKWEIGHT

#define DEFAULT_LOCKWEIGHT   0.75

weight used in a convex combination of conflict and variable locks

Definition at line 79 of file heur_conflictdiving.c.

Referenced by SCIPincludeHeurConflictdiving().

◆ DEFAULT_LIKECOEF

#define DEFAULT_LIKECOEF   FALSE

perform rounding like coefficient diving

Definition at line 80 of file heur_conflictdiving.c.

Referenced by SCIPincludeHeurConflictdiving().

◆ DEFAULT_MAXVIOL

#define DEFAULT_MAXVIOL   TRUE

prefer rounding direction with most violation

Definition at line 81 of file heur_conflictdiving.c.

Referenced by SCIPincludeHeurConflictdiving().

◆ DEFAULT_MINCONFLICTLOCKS

#define DEFAULT_MINCONFLICTLOCKS   5

threshold for penalizing the score

Definition at line 82 of file heur_conflictdiving.c.

Referenced by SCIPincludeHeurConflictdiving().

◆ MIN_RAND

#define MIN_RAND   1e-06

◆ MAX_RAND

#define MAX_RAND   1e-05

◆ divesetAvailableConflictdiving

#define divesetAvailableConflictdiving   NULL

Definition at line 492 of file heur_conflictdiving.c.

Referenced by SCIPincludeHeurConflictdiving().

Function Documentation

◆ SCIP_DECL_HEURCOPY()

static SCIP_DECL_HEURCOPY ( heurCopyConflictdiving )
static

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

Definition at line 100 of file heur_conflictdiving.c.

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

◆ assert() [1/7]

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() [2/7]

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

References HEUR_NAME.

◆ assert() [3/7]

assert ( scip ! = NULL)

References NULL.

◆ assert() [4/7]

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() [5/7]

assert ( SCIPheurGetNDivesets(heur) ,
0  )

◆ assert() [6/7]

assert ( SCIPheurGetDivesets(heur) ! = NULL)

References diveset, and NULL.

◆ assert() [7/7]

assert ( diveset ! = NULL)

References diveset, and NULL.

◆ if()

if ( SCIPgetNConflictConssFound(scip) = = 0)

pointer to store whether the candidate should be rounded upwards

Definition at line 190 of file heur_conflictdiving.c.

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

◆ getScore()

static SCIP_RETCODE getScore ( SCIP * scip,
SCIP_HEURDATA * heurdata,
SCIP_RANDNUMGEN * rng,
SCIP_DIVETYPE divetype,
SCIP_VAR * cand,
SCIP_Real candsol,
SCIP_Real candsfrac,
SCIP_Real * score,
SCIP_Bool * roundup )
static

calculate score variant 2: use a rounding strategy that tends towards infeasibility

Parameters
scipSCIP data structure
heurdataheuristic data
rngrandom number generator of the diveset
divetypedivetype of the heuristic
canddiving candidate
candsoldiving candidate solution
candsfracfractionality of the candidate solution
scorepointer to store the score
rounduppointer to store whether the candidate should be rounded upwards

Definition at line 315 of file heur_conflictdiving.c.

References assert(), heurdata, MAX_RAND, mayrounddown, mayroundup, MIN_RAND, NULL, roundup, SCIP_Bool, SCIP_DIVETYPE_INTEGRALITY, SCIP_DIVETYPE_SOS1VARIABLE, SCIP_INVALIDDATA, SCIP_LOCKTYPE_CONFLICT, SCIP_LOCKTYPE_MODEL, SCIP_OKAY, SCIP_PROBINGSCORE_PENALTYRATIO, SCIP_Real, SCIPABORT, SCIPerrorMessage, SCIPisEQ(), SCIPisFeasNegative(), SCIPisFeasPositive(), SCIPisGT(), SCIPisLT(), SCIPisZero(), SCIPrandomGetInt(), SCIPrandomGetReal(), SCIPvarGetNLocksDownType(), SCIPvarGetNLocksUpType(), and SCIPvarIsBinary().

Referenced by SCIP_DECL_DIVESETGETSCORE().

◆ SCIP_DECL_DIVESETGETSCORE()

static SCIP_DECL_DIVESETGETSCORE ( divesetGetScoreConflictdiving )
static

returns a score for the given candidate – the best candidate maximizes the diving score

Definition at line 458 of file heur_conflictdiving.c.

References assert(), diveset, getScore(), heurdata, NULL, roundup, SCIP_CALL, SCIP_DIVETYPE_SOS1VARIABLE, SCIP_OKAY, SCIPdivesetGetHeur(), SCIPdivesetGetRandnumgen(), SCIPheurGetData(), and SCIPvarIsBinary().

◆ SCIPincludeHeurConflictdiving()

Variable Documentation

◆ heurdata

heurdata = SCIPheurGetData(heur)

Definition at line 123 of file heur_conflictdiving.c.

◆ SCIP_OKAY

return SCIP_OKAY

Definition at line 129 of file heur_conflictdiving.c.

◆ diveset

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

execution method of primal heuristic

Definition at line 177 of file heur_conflictdiving.c.

◆ result

* result = SCIP_DELAYED

Definition at line 187 of file heur_conflictdiving.c.