Scippy

SCIP

Solving Constraint Integer Programs

Detailed Description

Local branching heuristic according to Fischetti and Lodi.

Author
Timo Berthold
Marc Pfetsch

Definition in file heur_localbranching.c.

#include "blockmemshell/memory.h"
#include "scip/cons_linear.h"
#include "scip/heuristics.h"
#include "scip/heur_localbranching.h"
#include "scip/pub_event.h"
#include "scip/pub_heur.h"
#include "scip/pub_message.h"
#include "scip/pub_misc.h"
#include "scip/pub_sol.h"
#include "scip/pub_var.h"
#include "scip/scip_branch.h"
#include "scip/scip_cons.h"
#include "scip/scip_copy.h"
#include "scip/scip_event.h"
#include "scip/scip_general.h"
#include "scip/scip_heur.h"
#include "scip/scip_mem.h"
#include "scip/scip_message.h"
#include "scip/scip_nodesel.h"
#include "scip/scip_numerics.h"
#include "scip/scip_param.h"
#include "scip/scip_prob.h"
#include "scip/scip_sol.h"
#include "scip/scip_solve.h"
#include "scip/scip_solvingstats.h"
#include <string.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   SCIP_HEURDISPCHAR_LNS
 
#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 DEFAULT_BESTSOLLIMIT   3 /* limit on number of improving incumbent solutions in sub-CIP */
 
#define EVENTHDLR_NAME   "Localbranching"
 
#define EVENTHDLR_DESC   "LP event handler for " HEUR_NAME " heuristic"
 
#define EXECUTE   0
 
#define WAITFORNEWSOL   1
 

Functions

static SCIP_RETCODE addLocalbranchingConstraintAndObjcutoff (SCIP *scip, SCIP *subscip, SCIP_HEUR *heur, SCIP_VAR **subvars)
 
static SCIP_DECL_EVENTEXEC (eventExecLocalbranching)
 
static SCIP_DECL_HEURCOPY (heurCopyLocalbranching)
 
static SCIP_DECL_HEURFREE (heurFreeLocalbranching)
 
static SCIP_DECL_HEURINIT (heurInitLocalbranching)
 
static SCIP_RETCODE setupAndSolveSubscipLocalbranching (SCIP *scip, SCIP *subscip, SCIP_HEUR *heur, SCIP_Longint nsubnodes, SCIP_RESULT *result)
 
static SCIP_DECL_HEUREXEC (heurExecLocalbranching)
 
SCIP_RETCODE SCIPincludeHeurLocalbranching (SCIP *scip)
 

Macro Definition Documentation

◆ HEUR_NAME

#define HEUR_NAME   "localbranching"

◆ HEUR_DESC

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

Definition at line 53 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ HEUR_DISPCHAR

#define HEUR_DISPCHAR   SCIP_HEURDISPCHAR_LNS

Definition at line 54 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ HEUR_PRIORITY

#define HEUR_PRIORITY   -1102000

Definition at line 55 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ HEUR_FREQ

#define HEUR_FREQ   -1

Definition at line 56 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ HEUR_FREQOFS

#define HEUR_FREQOFS   0

Definition at line 57 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ HEUR_MAXDEPTH

#define HEUR_MAXDEPTH   -1

Definition at line 58 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ HEUR_TIMING

#define HEUR_TIMING   SCIP_HEURTIMING_AFTERNODE

Definition at line 59 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ HEUR_USESSUBSCIP

#define HEUR_USESSUBSCIP   TRUE

does the heuristic use a secondary SCIP instance?

Definition at line 60 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ DEFAULT_NEIGHBORHOODSIZE

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

Definition at line 62 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ DEFAULT_NODESOFS

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

Definition at line 63 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ DEFAULT_MAXNODES

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

Definition at line 64 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ DEFAULT_MINIMPROVE

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

Definition at line 65 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ DEFAULT_MINNODES

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

Definition at line 66 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ DEFAULT_NODESQUOT

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

Definition at line 67 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ DEFAULT_LPLIMFAC

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

Definition at line 68 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ DEFAULT_NWAITINGNODES

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

Definition at line 69 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ DEFAULT_USELPROWS

#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:73

Definition at line 70 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ DEFAULT_COPYCUTS

#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:72

Definition at line 72 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ DEFAULT_BESTSOLLIMIT

#define DEFAULT_BESTSOLLIMIT   3 /* limit on number of improving incumbent solutions in sub-CIP */

Definition at line 75 of file heur_localbranching.c.

Referenced by SCIPincludeHeurLocalbranching().

◆ EVENTHDLR_NAME

#define EVENTHDLR_NAME   "Localbranching"

◆ EVENTHDLR_DESC

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

Definition at line 79 of file heur_localbranching.c.

Referenced by setupAndSolveSubscipLocalbranching().

◆ EXECUTE

#define EXECUTE   0

Definition at line 82 of file heur_localbranching.c.

Referenced by SCIP_DECL_HEUREXEC(), and setupAndSolveSubscipLocalbranching().

◆ WAITFORNEWSOL

#define WAITFORNEWSOL   1

Function Documentation

◆ addLocalbranchingConstraintAndObjcutoff()

static SCIP_RETCODE addLocalbranchingConstraintAndObjcutoff ( SCIP scip,
SCIP subscip,
SCIP_HEUR heur,
SCIP_VAR **  subvars 
)
static

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

Parameters
scipSCIP data structure
subscipthe subproblem created by localbranching
heurthe local branching heuristic
subvarsthe subproblem variables

Definition at line 122 of file heur_localbranching.c.

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

Referenced by setupAndSolveSubscipLocalbranching().

◆ SCIP_DECL_EVENTEXEC()

static SCIP_DECL_EVENTEXEC ( eventExecLocalbranching  )
static

event handler execution callback to interrupt the solution process

Definition at line 232 of file heur_localbranching.c.

References EVENTHDLR_NAME, NULL, SCIP_CALL, SCIP_EVENTTYPE_LPSOLVED, SCIP_OKAY, SCIPdebugMsg, SCIPeventGetType(), SCIPeventhdlrGetName(), SCIPgetNLPs(), and SCIPinterruptSolve().

◆ SCIP_DECL_HEURCOPY()

static SCIP_DECL_HEURCOPY ( heurCopyLocalbranching  )
static

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

Definition at line 262 of file heur_localbranching.c.

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

◆ SCIP_DECL_HEURFREE()

static SCIP_DECL_HEURFREE ( heurFreeLocalbranching  )
static

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

Definition at line 276 of file heur_localbranching.c.

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

◆ SCIP_DECL_HEURINIT()

static SCIP_DECL_HEURINIT ( heurInitLocalbranching  )
static

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

Definition at line 297 of file heur_localbranching.c.

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

◆ setupAndSolveSubscipLocalbranching()

static SCIP_RETCODE setupAndSolveSubscipLocalbranching ( SCIP scip,
SCIP subscip,
SCIP_HEUR heur,
SCIP_Longint  nsubnodes,
SCIP_RESULT result 
)
static

◆ SCIP_DECL_HEUREXEC()