Scippy

SCIP

Solving Constraint Integer Programs

Detailed Description

heuristic that tries to solve the problem without objective. In Gurobi, this heuristic is known as "Hail Mary"

Author: Timo Berthold

Definition in file heur_zeroobj.h.

#include "scip/scip.h"

Go to the source code of this file.

Functions
SCIP_RETCODE	SCIPapplyZeroobj (SCIP scip, SCIP_HEUR heur, SCIP_RESULT *result, SCIP_Real minimprove, SCIP_Longint nnodes)

SCIP_RETCODE	SCIPincludeHeurZeroobj (SCIP *scip)

Function Documentation

SCIP_RETCODE SCIPapplyZeroobj	(	SCIP *	scip,
		SCIP_HEUR *	heur,
		SCIP_RESULT *	result,
		SCIP_Real	minimprove,
		SCIP_Longint	nnodes
	)

main procedure of the zeroobj heuristic, creates and solves a sub-SCIP

Parameters

scip	original SCIP data structure
heur	heuristic data structure
result	result data structure
minimprove	factor by which zeroobj should at least improve the incumbent
nnodes	node limit for the subproblem

Definition at line 264 of file heur_zeroobj.c.

References createNewSol(), EVENTHDLR_DESC, EVENTHDLR_NAME, FALSE, HEUR_NAME, MAX, MIN, NULL, SCIP_Bool, SCIP_CALL, SCIP_DIDNOTFIND, SCIP_DIDNOTRUN, SCIP_EVENTTYPE_NODESOLVED, SCIP_FOUNDSOL, SCIP_OKAY, SCIP_PARAMSETTING_FAST, SCIP_PARAMSETTING_OFF, SCIP_PLUGINNOTFOUND, SCIP_Real, SCIPaddCoefLinear(), SCIPaddCons(), SCIPallocBufferArray, SCIPblkmem(), SCIPcalcHashtableSize(), SCIPcatchEvent(), SCIPchgVarLbGlobal(), SCIPchgVarObj(), SCIPchgVarUbGlobal(), SCIPcopy(), SCIPcreate(), SCIPcreateConsLinear(), SCIPdebugMessage, SCIPdropEvent(), SCIPerrorMessage, SCIPfeastol(), SCIPfindBranchrule(), SCIPfindConshdlr(), SCIPfindNodesel(), SCIPfree(), SCIPfreeBufferArray, SCIPgetDepth(), SCIPgetLowerbound(), SCIPgetMemExternEstim(), SCIPgetMemUsed(), SCIPgetNObjVars(), SCIPgetNSols(), SCIPgetNSolsFound(), SCIPgetRealParam(), SCIPgetSols(), SCIPgetSolvingTime(), SCIPgetUpperbound(), SCIPgetVarsData(), SCIPhashmapCreate(), SCIPhashmapFree(), SCIPhashmapGetImage(), SCIPheurGetData(), SCIPheurGetNCalls(), SCIPincludeEventhdlrBasic(), SCIPinfinity(), SCIPisFeasZero(), SCIPisInfinity(), SCIPisParamFixed(), SCIPprintStatistics(), SCIPreleaseCons(), SCIPsetBoolParam(), SCIPsetIntParam(), SCIPsetLongintParam(), SCIPsetPresolving(), SCIPsetRealParam(), SCIPsetSeparating(), SCIPsetSubscipsOff(), SCIPsolve(), SCIPsumepsilon(), SCIPtransformProb(), SCIPvarGetLbGlobal(), SCIPvarGetObj(), SCIPvarGetUbGlobal(), SCIPwarningMessage(), and TRUE.

Referenced by SCIP_DECL_HEUREXEC().

SCIP_RETCODE SCIPincludeHeurZeroobj ( SCIP * scip )

creates the zeroobj primal heuristic and includes it in SCIP

Parameters

scip	SCIP data structure

Definition at line 566 of file heur_zeroobj.c.

References DEFAULT_ADDALLSOLS, DEFAULT_MAXLPITERS, DEFAULT_MAXNODES, DEFAULT_MINIMPROVE, DEFAULT_MINNODES, DEFAULT_NODESOFS, DEFAULT_NODESQUOT, DEFAULT_ONLYWITHOUTSOL, FALSE, HEUR_DESC, HEUR_DISPCHAR, HEUR_FREQ, HEUR_FREQOFS, HEUR_MAXDEPTH, HEUR_NAME, HEUR_PRIORITY, HEUR_TIMING, HEUR_USESSUBSCIP, NULL, SCIP_CALL, SCIP_LONGINT_MAX, SCIP_OKAY, SCIPaddBoolParam(), SCIPaddLongintParam(), SCIPaddRealParam(), SCIPallocMemory, SCIPincludeHeurBasic(), SCIPsetHeurCopy(), SCIPsetHeurFree(), SCIPsetHeurInit(), and TRUE.

Referenced by SCIP_DECL_HEURCOPY(), and SCIPincludeDefaultPlugins().