Scippy

SCIP

Solving Constraint Integer Programs

heur_localbranching.c File Reference

Detailed Description

Local branching heuristic according to Fischetti and Lodi.

Author
Timo Berthold
Marc Pfetsch

Definition in file heur_localbranching.c.

#include <assert.h>
#include <string.h>
#include "scip/scip.h"
#include "scip/cons_linear.h"
#include "scip/scipdefplugins.h"
#include "scip/heur_localbranching.h"
#include "scip/pub_misc.h"

Go to the source code of this file.

Macros

#define HEUR_NAME   "localbranching"
 
#define HEUR_DESC   "local branching heuristic by Fischetti and Lodi"
 
#define HEUR_DISPCHAR   'L'
 
#define HEUR_PRIORITY   -1102000
 
#define HEUR_FREQ   -1
 
#define HEUR_FREQOFS   0
 
#define HEUR_MAXDEPTH   -1
 
#define HEUR_TIMING   SCIP_HEURTIMING_AFTERNODE
 
#define HEUR_USESSUBSCIP   TRUE
 
#define DEFAULT_NEIGHBORHOODSIZE   18 /* radius of the incumbents neighborhood to be searched */
 
#define DEFAULT_NODESOFS   1000 /* number of nodes added to the contingent of the total nodes */
 
#define DEFAULT_MAXNODES   10000 /* maximum number of nodes to regard in the subproblem */
 
#define DEFAULT_MINIMPROVE   0.01 /* factor by which localbranching should at least improve the incumbent */
 
#define DEFAULT_MINNODES   1000 /* minimum number of nodes required to start the subproblem */
 
#define DEFAULT_NODESQUOT   0.05 /* contingent of sub problem nodes in relation to original nodes */
 
#define DEFAULT_LPLIMFAC   1.5 /* factor by which the limit on the number of LP depends on the node limit */
 
#define DEFAULT_NWAITINGNODES   200 /* number of nodes without incumbent change that heuristic should wait */
 
#define DEFAULT_USELPROWS
 
#define DEFAULT_COPYCUTS
 
#define EVENTHDLR_NAME   "Localbranching"
 
#define EVENTHDLR_DESC   "LP event handler for " HEUR_NAME " heuristic"
 
#define EXECUTE   0
 
#define WAITFORNEWSOL   1
 

Functions

static SCIP_RETCODE createSubproblem (SCIP *scip, SCIP *subscip, SCIP_VAR **subvars)
 
static SCIP_RETCODE addLocalBranchingConstraint (SCIP *scip, SCIP *subscip, SCIP_VAR **subvars, SCIP_HEURDATA *heurdata)
 
static SCIP_RETCODE createNewSol (SCIP *scip, SCIP *subscip, SCIP_VAR **subvars, SCIP_HEUR *heur, SCIP_SOL *subsol, SCIP_Bool *success)
 
static SCIP_DECL_EVENTEXEC (eventExecLocalbranching)
 
static SCIP_DECL_HEURCOPY (heurCopyLocalbranching)
 
static SCIP_DECL_HEURFREE (heurFreeLocalbranching)
 
static SCIP_DECL_HEURINIT (heurInitLocalbranching)
 
static SCIP_DECL_HEUREXEC (heurExecLocalbranching)
 
SCIP_RETCODE SCIPincludeHeurLocalbranching (SCIP *scip)
 

Macro Definition Documentation

#define HEUR_NAME   "localbranching"
#define HEUR_DESC   "local branching heuristic by Fischetti and Lodi"

Definition at line 33 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

#define HEUR_DISPCHAR   'L'

Definition at line 34 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

#define HEUR_PRIORITY   -1102000

Definition at line 35 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

#define HEUR_FREQ   -1

Definition at line 36 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

#define HEUR_FREQOFS   0

Definition at line 37 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

#define HEUR_MAXDEPTH   -1

Definition at line 38 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

#define HEUR_TIMING   SCIP_HEURTIMING_AFTERNODE

Definition at line 39 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

#define HEUR_USESSUBSCIP   TRUE

does the heuristic use a secondary SCIP instance?

Definition at line 40 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

#define DEFAULT_NEIGHBORHOODSIZE   18 /* radius of the incumbents neighborhood to be searched */

Definition at line 42 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

#define DEFAULT_NODESOFS   1000 /* number of nodes added to the contingent of the total nodes */

Definition at line 43 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

#define DEFAULT_MAXNODES   10000 /* maximum number of nodes to regard in the subproblem */

Definition at line 44 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

#define DEFAULT_MINIMPROVE   0.01 /* factor by which localbranching should at least improve the incumbent */

Definition at line 45 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

#define DEFAULT_MINNODES   1000 /* minimum number of nodes required to start the subproblem */

Definition at line 46 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

#define DEFAULT_NODESQUOT   0.05 /* contingent of sub problem nodes in relation to original nodes */

Definition at line 47 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

#define DEFAULT_LPLIMFAC   1.5 /* factor by which the limit on the number of LP depends on the node limit */

Definition at line 48 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

#define DEFAULT_NWAITINGNODES   200 /* number of nodes without incumbent change that heuristic should wait */

Definition at line 49 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

#define DEFAULT_USELPROWS
Value:
FALSE /* should subproblem be created out of the rows in the LP rows,
* otherwise, the copy constructors of the constraints handlers are used */
#define FALSE
Definition: def.h:56

Definition at line 50 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

#define DEFAULT_COPYCUTS
Value:
TRUE /* if DEFAULT_USELPROWS is FALSE, then should all active cuts from the cutpool
* of the original scip be copied to constraints of the subscip
*/
#define TRUE
Definition: def.h:55

Definition at line 52 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

#define EVENTHDLR_NAME   "Localbranching"

Definition at line 57 of file heur_localbranching.c.

Referenced by SCIP_DECL_EVENTEXEC(), and SCIP_DECL_HEUREXEC().

#define EVENTHDLR_DESC   "LP event handler for " HEUR_NAME " heuristic"

Definition at line 58 of file heur_localbranching.c.

Referenced by SCIP_DECL_HEUREXEC().

#define EXECUTE   0

Definition at line 61 of file heur_localbranching.c.

Referenced by SCIP_DECL_HEUREXEC().

#define WAITFORNEWSOL   1

Definition at line 62 of file heur_localbranching.c.

Referenced by SCIP_DECL_HEUREXEC(), and SCIP_DECL_HEURINIT().

Function Documentation

static SCIP_RETCODE createSubproblem ( SCIP scip,
SCIP subscip,
SCIP_VAR **  subvars 
)
static

copies the problem of scip to the problem of subscip - only necessary if uselprows is false

Parameters
scipSCIP data structure of the original problem
subscipSCIP data structure of the subproblem
subvarsvariables of the subproblem

Definition at line 100 of file heur_localbranching.c.

References FALSE, SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIPaddCons(), SCIPallocBufferArray, SCIPcolGetVar(), SCIPcreateConsLinear(), SCIPfreeBufferArray, SCIPgetLPRowsData(), SCIPreleaseCons(), SCIProwGetCols(), SCIProwGetConstant(), SCIProwGetLhs(), SCIProwGetName(), SCIProwGetNNonz(), SCIProwGetRhs(), SCIProwGetVals(), SCIProwIsLocal(), SCIPvarGetProbindex(), and TRUE.

Referenced by SCIP_DECL_HEUREXEC().

static SCIP_RETCODE addLocalBranchingConstraint ( SCIP scip,
SCIP subscip,
SCIP_VAR **  subvars,
SCIP_HEURDATA heurdata 
)
static

create the extra constraint of local branching and add it to subscip

Parameters
scipSCIP data structure of the original problem
subscipSCIP data structure of the subproblem
subvarsvariables of the subproblem
heurdataheuristic's data structure

Definition at line 159 of file heur_localbranching.c.

References FALSE, NULL, SCIP_CALL, SCIP_MAXSTRLEN, SCIP_OKAY, SCIP_Real, SCIP_VARTYPE_BINARY, SCIPaddCons(), SCIPallocBufferArray, SCIPcreateConsLinear(), SCIPfreeBufferArray, SCIPgetBestSol(), SCIPgetProbName(), SCIPgetSolVal(), SCIPgetVarsData(), SCIPisFeasEQ(), SCIPisFeasIntegral(), SCIPreleaseCons(), SCIPsnprintf(), SCIPvarGetType(), and TRUE.

Referenced by SCIP_DECL_HEUREXEC().

static SCIP_RETCODE createNewSol ( SCIP scip,
SCIP subscip,
SCIP_VAR **  subvars,
SCIP_HEUR heur,
SCIP_SOL subsol,
SCIP_Bool success 
)
static

creates a new solution for the original problem by copying the solution of the subproblem

Parameters
scipSCIP data structure of the original problem
subscipSCIP data structure of the subproblem
subvarsthe variables of the subproblem
heurthe Localbranching heuristic
subsolsolution of the subproblem
successpointer to store, whether new solution was found

Definition at line 230 of file heur_localbranching.c.

References FALSE, NULL, SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIPallocBufferArray, SCIPcreateSol(), SCIPfreeBufferArray, SCIPgetNOrigVars(), SCIPgetSolVals(), SCIPgetVarsData(), SCIPsetSolVals(), SCIPtrySolFree(), and TRUE.

Referenced by SCIP_DECL_HEUREXEC().

static SCIP_DECL_EVENTEXEC ( eventExecLocalbranching  )
static
static SCIP_DECL_HEURCOPY ( heurCopyLocalbranching  )
static

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

Definition at line 310 of file heur_localbranching.c.

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

static SCIP_DECL_HEURFREE ( heurFreeLocalbranching  )
static

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

Definition at line 324 of file heur_localbranching.c.

References NULL, SCIP_OKAY, SCIPfreeMemory, SCIPheurGetData(), and SCIPheurSetData().

static SCIP_DECL_HEURINIT ( heurInitLocalbranching  )
static

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

Definition at line 345 of file heur_localbranching.c.

References NULL, SCIP_OKAY, SCIPheurGetData(), and WAITFORNEWSOL.

static SCIP_DECL_HEUREXEC ( heurExecLocalbranching  )
static

execution method of primal heuristic

Definition at line 370 of file heur_localbranching.c.

References addLocalBranchingConstraint(), createNewSol(), createSubproblem(), EVENTHDLR_DESC, EVENTHDLR_NAME, EXECUTE, FALSE, HEUR_NAME, MAX, MIN, NULL, SCIP_Bool, SCIP_CALL, SCIP_DELAYED, SCIP_DIDNOTFIND, SCIP_DIDNOTRUN, SCIP_EVENTTYPE_LPSOLVED, SCIP_FOUNDSOL, SCIP_Longint, SCIP_MAXSTRLEN, SCIP_OKAY, SCIP_PARAMSETTING_FAST, SCIP_PARAMSETTING_OFF, SCIP_PLUGINNOTFOUND, SCIP_Real, SCIP_STATUS_BESTSOLLIMIT, SCIP_STATUS_GAPLIMIT, SCIP_STATUS_INFEASIBLE, SCIP_STATUS_INFORUNBD, SCIP_STATUS_MEMLIMIT, SCIP_STATUS_NODELIMIT, SCIP_STATUS_OPTIMAL, SCIP_STATUS_RESTARTLIMIT, SCIP_STATUS_SOLLIMIT, SCIP_STATUS_STALLNODELIMIT, SCIP_STATUS_TIMELIMIT, SCIP_STATUS_TOTALNODELIMIT, SCIP_STATUS_UNBOUNDED, SCIP_STATUS_UNKNOWN, SCIP_STATUS_USERINTERRUPT, SCIPallocBufferArray, SCIPblkmem(), SCIPcalcHashtableSize(), SCIPcatchEvent(), SCIPcopy(), SCIPcopyCuts(), SCIPcopyVars(), SCIPcreate(), SCIPcreateProb(), SCIPdebug, SCIPdebugMessage, SCIPdropEvent(), SCIPerrorMessage, SCIPfindBranchrule(), SCIPfindConshdlr(), SCIPfindNodesel(), SCIPfree(), SCIPfreeBufferArray, SCIPgetBestSol(), SCIPgetLowerbound(), SCIPgetMemExternEstim(), SCIPgetMemUsed(), SCIPgetNBinVars(), SCIPgetNNodes(), SCIPgetNSols(), SCIPgetProbName(), SCIPgetRealParam(), SCIPgetSolNodenum(), SCIPgetSolOrigObj(), SCIPgetSols(), SCIPgetSolvingTime(), SCIPgetStatus(), SCIPgetUpperbound(), SCIPgetVarsData(), SCIPhashmapCreate(), SCIPhashmapFree(), SCIPhashmapGetImage(), SCIPheurGetData(), SCIPheurGetName(), SCIPheurGetNBestSolsFound(), SCIPheurGetNCalls(), SCIPincludeDefaultPlugins(), SCIPincludeEventhdlrBasic(), SCIPinfinity(), SCIPisInfinity(), SCIPisParamFixed(), SCIPisStopped(), SCIPprintStatistics(), SCIPsetBoolParam(), SCIPsetIntParam(), SCIPsetLongintParam(), SCIPsetObjlimit(), SCIPsetPresolving(), SCIPsetRealParam(), SCIPsetSeparating(), SCIPsetSubscipsOff(), SCIPsnprintf(), SCIPsolGetHeur(), SCIPsolIsOriginal(), SCIPsolve(), SCIPsumepsilon(), SCIPtransformProb(), SCIPwarningMessage(), TRUE, and WAITFORNEWSOL.