Scippy

SCIP

Solving Constraint Integer Programs

Macros | Functions
heur_indicator.c File Reference

Detailed Description

handle partial solutions for linear problems with indicators and otherwise continuous variables

Author
Marc Pfetsch

For linear problems with indicators and otherwise continuous variables, the indicator constraint handler can produce partial solutions, i.e., values for the indicator variables. This partial solution can be passed to this heuristic, which then fixes these values and solves an LP. Additionally a local search for a better solution is added.

Definition in file heur_indicator.c.

#include <assert.h>
#include <string.h>
#include "scip/scip.h"
#include "scip/heur_indicator.h"
#include "scip/cons_indicator.h"

Go to the source code of this file.

Macros

#define HEUR_NAME   "indicator"
 
#define HEUR_DESC   "indicator heuristic to create feasible solutions from values for indicator variables"
 
#define HEUR_DISPCHAR   'A'
 
#define HEUR_PRIORITY   -20200
 
#define HEUR_FREQ   1
 
#define HEUR_FREQOFS   0
 
#define HEUR_MAXDEPTH   -1
 
#define HEUR_TIMING   SCIP_HEURTIMING_DURINGLPLOOP
 
#define HEUR_USESSUBSCIP   FALSE
 
#define DEFAULT_ONEOPT   TRUE
 
#define DEFAULT_IMPROVESOLS   FALSE
 

Functions

static SCIP_RETCODE tryOneOpt (SCIP *scip, SCIP_HEUR *heur, SCIP_HEURDATA *heurdata, int nindconss, SCIP_CONS **indconss, SCIP_Bool *solcand, int *nfoundsols)
 
static SCIP_RETCODE trySolCandidate (SCIP *scip, SCIP_HEUR *heur, SCIP_HEURDATA *heurdata, int nindconss, SCIP_CONS **indconss, SCIP_Bool *solcand, int *nfoundsols)
 
static SCIP_DECL_HEURCOPY (heurCopyIndicator)
 
static SCIP_DECL_HEURINIT (heurInitIndicator)
 
static SCIP_DECL_HEURFREE (heurFreeIndicator)
 
static SCIP_DECL_HEUREXEC (heurExecIndicator)
 
SCIP_RETCODE SCIPincludeHeurIndicator (SCIP *scip)
 
SCIP_RETCODE SCIPheurPassIndicator (SCIP *scip, SCIP_HEUR *heur, int nindconss, SCIP_CONS **indconss, SCIP_Bool *solcand)
 

Macro Definition Documentation

◆ HEUR_NAME

#define HEUR_NAME   "indicator"

Definition at line 33 of file heur_indicator.c.

Referenced by SCIP_DECL_HEURCOPY(), SCIPheurPassIndicator(), and SCIPincludeHeurIndicator().

◆ HEUR_DESC

#define HEUR_DESC   "indicator heuristic to create feasible solutions from values for indicator variables"

Definition at line 34 of file heur_indicator.c.

Referenced by SCIPincludeHeurIndicator().

◆ HEUR_DISPCHAR

#define HEUR_DISPCHAR   'A'

Definition at line 35 of file heur_indicator.c.

Referenced by SCIPincludeHeurIndicator().

◆ HEUR_PRIORITY

#define HEUR_PRIORITY   -20200

Definition at line 36 of file heur_indicator.c.

Referenced by SCIPincludeHeurIndicator().

◆ HEUR_FREQ

#define HEUR_FREQ   1

Definition at line 37 of file heur_indicator.c.

Referenced by SCIPincludeHeurIndicator().

◆ HEUR_FREQOFS

#define HEUR_FREQOFS   0

Definition at line 38 of file heur_indicator.c.

Referenced by SCIPincludeHeurIndicator().

◆ HEUR_MAXDEPTH

#define HEUR_MAXDEPTH   -1

Definition at line 39 of file heur_indicator.c.

Referenced by SCIPincludeHeurIndicator().

◆ HEUR_TIMING

#define HEUR_TIMING   SCIP_HEURTIMING_DURINGLPLOOP

Definition at line 40 of file heur_indicator.c.

Referenced by SCIPincludeHeurIndicator().

◆ HEUR_USESSUBSCIP

#define HEUR_USESSUBSCIP   FALSE

does the heuristic use a secondary SCIP instance?

Definition at line 41 of file heur_indicator.c.

Referenced by SCIPincludeHeurIndicator().

◆ DEFAULT_ONEOPT

#define DEFAULT_ONEOPT   TRUE

whether the one-opt heuristic should be started

Definition at line 43 of file heur_indicator.c.

Referenced by SCIPincludeHeurIndicator().

◆ DEFAULT_IMPROVESOLS

#define DEFAULT_IMPROVESOLS   FALSE

Try to improve other solutions by one-opt?

Definition at line 44 of file heur_indicator.c.

Referenced by SCIPincludeHeurIndicator().

Function Documentation

◆ tryOneOpt()

static SCIP_RETCODE tryOneOpt ( SCIP *  scip,
SCIP_HEUR *  heur,
SCIP_HEURDATA *  heurdata,
int  nindconss,
SCIP_CONS **  indconss,
SCIP_Bool *  solcand,
int *  nfoundsols 
)
static

try one-opt on given solution

Parameters
scipSCIP data structure
heurindicator heuristic
heurdataheuristic data
nindconssnumber of indicator constraints
indconssindicator constraints
solcandvalues for indicator variables in partial solution
nfoundsolsnumber of solutions found

Definition at line 65 of file heur_indicator.c.

References FALSE, NULL, SCIP_Bool, SCIP_CALL, SCIP_LPSOLSTAT_OPTIMAL, SCIP_MAXTREEDEPTH, SCIP_OKAY, SCIPbacktrackProbing(), SCIPchgVarLbProbing(), SCIPchgVarUbProbing(), SCIPconsIsActive(), SCIPcreateSol(), SCIPdebugMsg, SCIPendProbing(), SCIPgetBinaryVarIndicator(), SCIPgetDepth(), SCIPgetLPSolstat(), SCIPgetSolTransObj(), SCIPlinkLPSol(), SCIPnewProbingNode(), SCIPpropagateProbing(), SCIPsolveProbingLP(), SCIPstartProbing(), SCIPtrySolFree(), SCIPvarGetLbLocal(), SCIPvarGetUbLocal(), and TRUE.

Referenced by SCIP_DECL_HEUREXEC(), and trySolCandidate().

◆ trySolCandidate()

static SCIP_RETCODE trySolCandidate ( SCIP *  scip,
SCIP_HEUR *  heur,
SCIP_HEURDATA *  heurdata,
int  nindconss,
SCIP_CONS **  indconss,
SCIP_Bool *  solcand,
int *  nfoundsols 
)
static

try given solution

Parameters
scipSCIP data structure
heurindicator heuristic
heurdataheuristic data
nindconssnumber of indicator constraints
indconssindicator constraints
solcandvalues for indicator variables in partial solution
nfoundsolsnumber of solutions found

Definition at line 199 of file heur_indicator.c.

References FALSE, NULL, SCIP_Bool, SCIP_CALL, SCIP_LPSOLSTAT_OPTIMAL, SCIP_MAXTREEDEPTH, SCIP_OKAY, SCIPchgVarLbProbing(), SCIPchgVarUbProbing(), SCIPconsIsActive(), SCIPcreateSol(), SCIPdebugMsg, SCIPendProbing(), SCIPgetBinaryVarIndicator(), SCIPgetDepth(), SCIPgetLPSolstat(), SCIPgetSolTransObj(), SCIPlinkLPSol(), SCIPnewProbingNode(), SCIPprintSol(), SCIPpropagateProbing(), SCIPsolveProbingLP(), SCIPstartProbing(), SCIPtrySolFree(), SCIPvarGetLbLocal(), SCIPvarGetUbLocal(), TRUE, and tryOneOpt().

Referenced by SCIP_DECL_HEUREXEC().

◆ SCIP_DECL_HEURCOPY()

static SCIP_DECL_HEURCOPY ( heurCopyIndicator  )
static

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

Definition at line 341 of file heur_indicator.c.

References HEUR_NAME, NULL, SCIP_CALL, SCIP_OKAY, SCIPheurGetName(), and SCIPincludeHeurIndicator().

◆ SCIP_DECL_HEURINIT()

static SCIP_DECL_HEURINIT ( heurInitIndicator  )
static

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

Definition at line 355 of file heur_indicator.c.

References NULL, SCIP_OKAY, SCIPfindConshdlr(), SCIPheurGetData(), and SCIPwarningMessage().

◆ SCIP_DECL_HEURFREE()

static SCIP_DECL_HEURFREE ( heurFreeIndicator  )
static

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

Definition at line 380 of file heur_indicator.c.

References NULL, SCIP_OKAY, SCIPfreeBlockMemory, SCIPfreeBlockMemoryArrayNull, SCIPheurGetData(), and SCIPheurSetData().

◆ SCIP_DECL_HEUREXEC()

static SCIP_DECL_HEUREXEC ( heurExecIndicator  )
static

execution method of primal heuristic

Definition at line 404 of file heur_indicator.c.

References FALSE, NULL, SCIP_Bool, SCIP_CALL, SCIP_DIDNOTFIND, SCIP_DIDNOTRUN, SCIP_FOUNDSOL, SCIP_OKAY, SCIP_Real, SCIPallocBufferArray, SCIPconshdlrGetConss(), SCIPconshdlrGetNConss(), SCIPconsIsActive(), SCIPdebugMsg, SCIPfreeBlockMemoryArray, SCIPfreeBufferArray, SCIPgetBestSol(), SCIPgetBinaryVarIndicator(), SCIPgetNBinVars(), SCIPgetNIntVars(), SCIPgetSolOrigObj(), SCIPgetSolVal(), SCIPgetSubscipDepth(), SCIPheurGetData(), SCIPisFeasIntegral(), SCIPsolGetHeur(), TRUE, tryOneOpt(), and trySolCandidate().