Detailed Description

rounding locks primal heuristic

Author: Michael Winkler; Gerald Gamrath

Definition in file heur_locks.c.

#include "blockmemshell/memory.h"
#include "scip/heur_locks.h"
#include "scip/pub_cons.h"
#include "scip/pub_heur.h"
#include "scip/pub_lp.h"
#include "scip/pub_message.h"
#include "scip/pub_misc.h"
#include "scip/pub_var.h"
#include "scip/scip_branch.h"
#include "scip/scip_cons.h"
#include "scip/scip_copy.h"
#include "scip/scip_general.h"
#include "scip/scip_heur.h"
#include "scip/scip_lp.h"
#include "scip/scip_mem.h"
#include "scip/scip_message.h"
#include "scip/scip_numerics.h"
#include "scip/scip_param.h"
#include "scip/scip_prob.h"
#include "scip/scip_probing.h"
#include "scip/scip_randnumgen.h"
#include "scip/scip_sol.h"
#include "scip/scip_solve.h"
#include "scip/scip_solvingstats.h"
#include "scip/scip_timing.h"
#include "scip/scip_tree.h"
#include <string.h>

Go to the source code of this file.

Macros
#define	HEUR_NAME "locks"

#define	HEUR_DESC "heuristic that fixes variables based on their rounding locks"

#define	HEUR_DISPCHAR 'k'

#define	HEUR_PRIORITY 3000

#define	HEUR_FREQ 0

#define	HEUR_FREQOFS 0

#define	HEUR_MAXDEPTH -1

#define	HEUR_TIMING SCIP_HEURTIMING_BEFORENODE

#define	HEUR_USESSUBSCIP TRUE

#define	DEFAULT_MAXNODES 5000LL

#define	DEFAULT_ROUNDUPPROBABILITY 0.67

#define	DEFAULT_MINFIXINGRATE 0.65

#define	DEFAULT_MINIMPROVE 0.01

#define	DEFAULT_MINNODES 500LL

#define	DEFAULT_NODESOFS 500LL

#define	DEFAULT_NODESQUOT 0.1

#define	DEFAULT_MAXPROPROUNDS 2

#define	DEFAULT_UPDATELOCKS TRUE

#define	DEFAULT_COPYCUTS TRUE

#define	DEFAULT_USEFINALSUBMIP TRUE

#define	DEFAULT_RANDSEED 73

#define	heurInitsolLocks NULL

#define	heurExitsolLocks NULL

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

static	SCIP_DECL_HEURCOPY (heurCopyLocks)

static	SCIP_DECL_HEURFREE (heurFreeLocks)

static	SCIP_DECL_HEURINIT (heurInitLocks)

static	SCIP_DECL_HEUREXIT (heurExitLocks)

SCIP_RETCODE	SCIPapplyLockFixings (SCIP scip, SCIP_HEURDATA heurdata, SCIP_Bool cutoff, SCIP_Bool allrowsfulfilled)

static	SCIP_DECL_HEUREXEC (heurExecLocks)

SCIP_RETCODE	SCIPincludeHeurLocks (SCIP *scip)

Macro Definition Documentation

◆ HEUR_NAME

#define HEUR_NAME "locks"

Definition at line 52 of file heur_locks.c.

Referenced by SCIP_DECL_HEUREXEC(), and SCIPapplyLockFixings().

◆ HEUR_DESC

#define HEUR_DESC "heuristic that fixes variables based on their rounding locks"

Definition at line 53 of file heur_locks.c.

◆ HEUR_DISPCHAR

#define HEUR_DISPCHAR 'k'

Definition at line 54 of file heur_locks.c.

◆ HEUR_PRIORITY

#define HEUR_PRIORITY 3000

Definition at line 55 of file heur_locks.c.

◆ HEUR_FREQ

#define HEUR_FREQ 0

Definition at line 56 of file heur_locks.c.

◆ HEUR_FREQOFS

#define HEUR_FREQOFS 0

Definition at line 57 of file heur_locks.c.

◆ HEUR_MAXDEPTH

#define HEUR_MAXDEPTH -1

Definition at line 58 of file heur_locks.c.

◆ HEUR_TIMING

#define HEUR_TIMING SCIP_HEURTIMING_BEFORENODE

Definition at line 59 of file heur_locks.c.

◆ HEUR_USESSUBSCIP

#define HEUR_USESSUBSCIP TRUE

does the heuristic use a secondary SCIP instance?

Definition at line 60 of file heur_locks.c.

◆ DEFAULT_MAXNODES

#define DEFAULT_MAXNODES 5000LL

maximum number of nodes to regard in the subproblem

Definition at line 62 of file heur_locks.c.

◆ DEFAULT_ROUNDUPPROBABILITY

#define DEFAULT_ROUNDUPPROBABILITY 0.67

probability for rounding a variable up in case of ties

Definition at line 63 of file heur_locks.c.

◆ DEFAULT_MINFIXINGRATE

#define DEFAULT_MINFIXINGRATE 0.65

minimum percentage of variables that have to be fixed

Definition at line 64 of file heur_locks.c.

◆ DEFAULT_MINIMPROVE

#define DEFAULT_MINIMPROVE 0.01

factor by which locks heuristic should at least improve the incumbent

Definition at line 65 of file heur_locks.c.

◆ DEFAULT_MINNODES

#define DEFAULT_MINNODES 500LL

minimum number of nodes to regard in the subproblem

Definition at line 70 of file heur_locks.c.

◆ DEFAULT_NODESOFS

#define DEFAULT_NODESOFS 500LL

number of nodes added to the contingent of the total nodes

Definition at line 71 of file heur_locks.c.

◆ DEFAULT_NODESQUOT

#define DEFAULT_NODESQUOT 0.1

subproblem nodes in relation to nodes of the original problem

Definition at line 72 of file heur_locks.c.

◆ DEFAULT_MAXPROPROUNDS

#define DEFAULT_MAXPROPROUNDS 2

maximum number of propagation rounds during probing

Definition at line 73 of file heur_locks.c.

◆ DEFAULT_UPDATELOCKS

#define DEFAULT_UPDATELOCKS TRUE

should the locks be updated based on LP rows?

Definition at line 74 of file heur_locks.c.

◆ DEFAULT_COPYCUTS

#define DEFAULT_COPYCUTS TRUE

should all active cuts from the cutpool of the original scip be copied to constraints of the subscip?

Definition at line 75 of file heur_locks.c.

◆ DEFAULT_USEFINALSUBMIP

#define DEFAULT_USEFINALSUBMIP TRUE

should a final sub-MIP be solved to construct a feasible solution if the LP was not roundable?

Definition at line 78 of file heur_locks.c.

◆ DEFAULT_RANDSEED

#define DEFAULT_RANDSEED 73

initial random seed

Definition at line 81 of file heur_locks.c.

◆ heurInitsolLocks

#define heurInitsolLocks NULL

Definition at line 227 of file heur_locks.c.

◆ heurExitsolLocks

#define heurExitsolLocks NULL

Definition at line 228 of file heur_locks.c.

Function Documentation

◆ createNewSol()

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

static

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

Parameters

scip	original SCIP data structure
subscip	SCIP structure of the subproblem
subvars	the variables of the subproblem
newsol	working solution
subsol	solution of the subproblem
success	used to store whether new solution was found or not

Definition at line 109 of file heur_locks.c.

References FALSE, NULL, SCIP_CALL, SCIP_DECL_HEURCOPY(), SCIP_OKAY, SCIP_Real, SCIPallocBufferArray, SCIPfreeBufferArray, SCIPgetNOrigVars(), SCIPgetSolOrigObj(), SCIPgetSolVals(), SCIPgetVarsData(), SCIPisInfinity(), SCIPsetSolVals(), SCIPtrySol(), and TRUE.

Referenced by SCIP_DECL_HEUREXEC().

◆ SCIP_DECL_HEURCOPY()

static SCIP_DECL_HEURCOPY ( heurCopyLocks )

static

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

Definition at line 159 of file heur_locks.c.

Referenced by createNewSol().

◆ SCIP_DECL_HEURFREE()

static SCIP_DECL_HEURFREE ( heurFreeLocks )

static

free method for primal heuristic plugins (called when SCIP is exiting)

Definition at line 173 of file heur_locks.c.

◆ SCIP_DECL_HEURINIT()

static SCIP_DECL_HEURINIT ( heurInitLocks )

static

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

Definition at line 191 of file heur_locks.c.

◆ SCIP_DECL_HEUREXIT()

static SCIP_DECL_HEUREXIT ( heurExitLocks )

static

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

Definition at line 211 of file heur_locks.c.

◆ SCIPapplyLockFixings()

SCIP_RETCODE SCIPapplyLockFixings	(	SCIP *	scip,
		SCIP_HEURDATA *	heurdata,
		SCIP_Bool *	cutoff,
		SCIP_Bool *	allrowsfulfilled
	)

apply fix-and-propagate scheme based on variable locks

Note: probing mode of SCIP needs to be enabled before

Parameters

scip	SCIP data structure
heurdata	primal heuristic data
cutoff	pointer to store if a cutoff was detected
allrowsfulfilled	pointer to store if all rows became redundant

Definition at line 234 of file heur_locks.c.

References FALSE, HEUR_NAME, NULL, r, REALABS, SCIP_Bool, SCIP_CALL, SCIP_DECL_HEUREXEC(), SCIP_LOCKTYPE_MODEL, SCIP_MAXTREEDEPTH, SCIP_OKAY, SCIP_Real, SCIP_VARSTATUS_COLUMN, SCIP_VARTYPE_BINARY, SCIPallocBufferArray, SCIPallocClearBufferArray, SCIPbacktrackProbing(), SCIPcolGetNNonz(), SCIPcolGetRows(), SCIPcolGetVals(), SCIPcolGetVar(), SCIPconshdlrGetNCheckConss(), SCIPdebug, SCIPdebugMsg, SCIPduplicateBufferArray, SCIPfindConshdlr(), SCIPfindHeur(), SCIPfixVarProbing(), SCIPfreeBufferArray, SCIPfreeBufferArrayNull, SCIPgetDepth(), SCIPgetLPRowsData(), SCIPgetNCheckConss(), SCIPgetNConss(), SCIPgetNLPRows(), SCIPgetProbingDepth(), SCIPgetRowMaxActivity(), SCIPgetRowMinActivity(), SCIPgetVarsData(), SCIPheurGetData(), SCIPinProbing(), SCIPisFeasGE(), SCIPisFeasGT(), SCIPisFeasLE(), SCIPisFeasLT(), SCIPisInfinity(), SCIPisPositive(), SCIPisStopped(), SCIPnewProbingNode(), SCIPprintRow(), SCIPpropagateProbing(), SCIPrandomGetReal(), SCIProwGetCols(), SCIProwGetLhs(), SCIProwGetLPPos(), SCIProwGetName(), SCIProwGetNNonz(), SCIProwGetRank(), SCIProwGetRhs(), SCIProwGetVals(), SCIPvarGetCol(), SCIPvarGetLbLocal(), SCIPvarGetName(), SCIPvarGetNLocksDownType(), SCIPvarGetNLocksUpType(), SCIPvarGetObj(), SCIPvarGetProbindex(), SCIPvarGetStatus(), SCIPvarGetType(), SCIPvarGetUbLocal(), TRUE, and w.

Referenced by applyVbounds(), and SCIP_DECL_HEUREXEC().

◆ SCIP_DECL_HEUREXEC()

static SCIP_DECL_HEUREXEC ( heurExecLocks )

static

execution method of primal heuristic

Definition at line 698 of file heur_locks.c.

References createNewSol(), FALSE, HEUR_NAME, MIN, NULL, SCIP_Bool, SCIP_CALL, SCIP_CALL_ABORT, SCIP_DIDNOTFIND, SCIP_FOUNDSOL, SCIP_Longint, SCIP_LONGINT_FORMAT, SCIP_LPSOLSTAT_INFEASIBLE, SCIP_LPSOLSTAT_OBJLIMIT, SCIP_LPSOLSTAT_OPTIMAL, SCIP_OKAY, SCIP_PARAMSETTING_FAST, SCIP_PARAMSETTING_OFF, SCIP_Real, SCIPallocBufferArray, SCIPapplyLockFixings(), SCIPblkmem(), SCIPcheckCopyLimits(), SCIPcheckSol(), SCIPconstructLP(), SCIPcopy(), SCIPcopyCuts(), SCIPcopyLimits(), SCIPcreate(), SCIPcreateSol(), SCIPcutoffNode(), SCIPdebug, SCIPdebugMsg, SCIPenableVarHistory(), SCIPendProbing(), SCIPfindBranchrule(), SCIPfindConshdlr(), SCIPflushLP(), SCIPfree(), SCIPfreeBufferArray, SCIPfreeSol(), SCIPgetBoolParam(), SCIPgetCurrentNode(), SCIPgetLowerbound(), SCIPgetLPObjval(), SCIPgetLPSolstat(), SCIPgetNConss(), SCIPgetNLPIterations(), SCIPgetNLPRows(), SCIPgetNNodes(), SCIPgetNPseudoBranchCands(), SCIPgetNSols(), SCIPgetNVars(), SCIPgetSols(), SCIPgetSolvingTime(), SCIPgetStatus(), SCIPgetUpperbound(), SCIPgetVarsData(), SCIPhashmapCreate(), SCIPhashmapFree(), SCIPhashmapGetImage(), SCIPheurGetData(), SCIPheurGetNBestSolsFound(), SCIPheurGetNCalls(), SCIPincludeHeurLocks(), SCIPisInfinity(), SCIPisParamFixed(), SCIPisStopped(), SCIPlinkLPSol(), SCIPpresolve(), SCIPprintSol(), SCIPprintStatistics(), SCIProundSol(), SCIPsetBoolParam(), SCIPsetIntParam(), SCIPsetLongintParam(), SCIPsetObjlimit(), SCIPsetPresolving(), SCIPsetSeparating(), SCIPsetSubscipsOff(), SCIPsolve(), SCIPsolveProbingLP(), SCIPstartProbing(), SCIPsumepsilon(), SCIPtrySol(), SCIPwarningMessage(), and TRUE.

Referenced by SCIPapplyLockFixings().

SCIP

Detailed Description

Macros

Functions

Macro Definition Documentation

◆ HEUR_NAME

◆ HEUR_DESC

◆ HEUR_DISPCHAR

◆ HEUR_PRIORITY

◆ HEUR_FREQ

◆ HEUR_FREQOFS

◆ HEUR_MAXDEPTH

◆ HEUR_TIMING

◆ HEUR_USESSUBSCIP

◆ DEFAULT_MAXNODES

◆ DEFAULT_ROUNDUPPROBABILITY

◆ DEFAULT_MINFIXINGRATE

◆ DEFAULT_MINIMPROVE

◆ DEFAULT_MINNODES

◆ DEFAULT_NODESOFS

◆ DEFAULT_NODESQUOT

◆ DEFAULT_MAXPROPROUNDS

◆ DEFAULT_UPDATELOCKS

◆ DEFAULT_COPYCUTS

◆ DEFAULT_USEFINALSUBMIP

◆ DEFAULT_RANDSEED

◆ heurInitsolLocks

◆ heurExitsolLocks

Function Documentation

◆ createNewSol()

◆ SCIP_DECL_HEURCOPY()

◆ SCIP_DECL_HEURFREE()

◆ SCIP_DECL_HEURINIT()

◆ SCIP_DECL_HEUREXIT()

◆ SCIPapplyLockFixings()

◆ SCIP_DECL_HEUREXEC()