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LNS heuristic that finds the optimal rounding to a given point.
- Author
- Timo Berthold
RENS is a large neighborhood search start heuristic, i.e., unlike other LNS heuristics, it does not need a known feasible solution. It solves a sub-SCIP that is created by fixing variables which take an integral value in a given LP or NLP solution. For the remaining integer variables, the bounds get tightened to the two nearest integral values.
Definition in file heur_rens.h.
Go to the source code of this file.
creates RENS primal heuristic and includes it in SCIP
creates the rens primal heuristic and includes it in SCIP
- Parameters
-
Definition at line 875 of file heur_rens.c.
References DEFAULT_ADDALLSOLS, DEFAULT_BINARYBOUNDS, DEFAULT_COPYCUTS, DEFAULT_EXTRATIME, DEFAULT_FULLSCALE, DEFAULT_LPLIMFAC, DEFAULT_MAXNODES, DEFAULT_MINFIXINGRATE, DEFAULT_MINIMPROVE, DEFAULT_MINNODES, DEFAULT_NODESOFS, DEFAULT_NODESQUOT, DEFAULT_STARTSOL, DEFAULT_USELPROWS, 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, SCIP_REAL_MAX, SCIPaddBoolParam(), SCIPaddCharParam(), SCIPaddLongintParam(), SCIPaddRealParam(), SCIPallocMemory, SCIPincludeHeurBasic(), SCIPsetHeurCopy(), SCIPsetHeurFree(), SCIPsetHeurInit(), STARTSOL_CHOICES, and TRUE.
Referenced by SCIP_DECL_HEURCOPY(), and SCIPincludeDefaultPlugins().
main procedure of the RENS heuristic, creates and solves a sub-SCIP
- Parameters
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| scip | original SCIP data structure |
| heur | heuristic data structure |
| result | result data structure |
| minfixingrate | minimum percentage of integer variables that have to be fixed |
| minimprove | factor by which RENS should at least improve the incumbent |
| maxnodes | maximum number of nodes for the subproblem |
| nstallnodes | number of stalling nodes for the subproblem |
| startsol | solution used for fixing values ('l'p relaxation, 'n'lp relaxation) |
| binarybounds | should general integers get binary bounds [floor(.),ceil(.)]? |
| uselprows | should subproblem be created out of the rows in the LP rows? |
Definition at line 405 of file heur_rens.c.
References computeFixingrate(), createNewSol(), createSubproblem(), EVENTHDLR_DESC, EVENTHDLR_NAME, FALSE, HEUR_NAME, MAX, MIN, NULL, SCIP_Bool, SCIP_CALL, SCIP_DIDNOTFIND, SCIP_DIDNOTRUN, SCIP_EVENTTYPE_LPSOLVED, SCIP_FOUNDSOL, SCIP_MAXSTRLEN, SCIP_OKAY, SCIP_PARAMSETTING_FAST, SCIP_PARAMSETTING_OFF, SCIP_PLUGINNOTFOUND, SCIP_Real, SCIPallocBufferArray, SCIPblkmem(), SCIPcalcHashtableSize(), SCIPcatchEvent(), SCIPcopy(), SCIPcopyCuts(), SCIPcopyVars(), SCIPcreate(), SCIPcreateProb(), SCIPdebug, SCIPdebugMessage, SCIPdropEvent(), SCIPerrorMessage, SCIPfindBranchrule(), SCIPfindConshdlr(), SCIPfindNodesel(), SCIPfree(), SCIPfreeBufferArray, SCIPgetBestSol(), SCIPgetLowerbound(), SCIPgetMemExternEstim(), SCIPgetMemUsed(), SCIPgetNConss(), SCIPgetNNodes(), SCIPgetNOrigVars(), SCIPgetNSols(), SCIPgetNVars(), SCIPgetPrimalbound(), SCIPgetProbName(), SCIPgetRealParam(), SCIPgetSols(), SCIPgetSolvingTime(), SCIPgetUpperbound(), SCIPgetVarsData(), SCIPhashmapCreate(), SCIPhashmapFree(), SCIPhashmapGetImage(), SCIPheurGetData(), SCIPincludeDefaultPlugins(), SCIPincludeEventhdlrBasic(), SCIPinfinity(), SCIPisInfinity(), SCIPisParamFixed(), SCIPmergeVariableStatistics(), SCIPpresolve(), SCIPprintStatistics(), SCIPsetBoolParam(), SCIPsetIntParam(), SCIPsetLongintParam(), SCIPsetObjlimit(), SCIPsetPresolving(), SCIPsetRealParam(), SCIPsetSeparating(), SCIPsetSubscipsOff(), SCIPsnprintf(), SCIPsolGetNodenum(), SCIPsolve(), SCIPstatisticPrintf, SCIPsumepsilon(), SCIPtransformProb(), SCIPwarningMessage(), and TRUE.
Referenced by SCIP_DECL_HEUREXEC().
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