heur_rens.h File Reference

Detailed Description

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.

#include "scip/scip.h"

Go to the source code of this file.

Functions
SCIP_RETCODE	SCIPincludeHeurRens (SCIP *scip)
SCIP_RETCODE	SCIPapplyRens (SCIP *scip, SCIP_HEUR *heur, SCIP_RESULT *result, SCIP_Real minfixingrate, SCIP_Real minimprove, SCIP_Longint maxnodes, SCIP_Longint nstallnodes, char startsol, SCIP_Bool binarybounds, SCIP_Bool uselprows)

Function Documentation

SCIP_RETCODE SCIPincludeHeurRens

(

SCIP *

scip

)

creates RENS primal heuristic and includes it in SCIP

Parameters

scip	SCIP data structure

SCIP_RETCODE SCIPapplyRens	(	SCIP *	scip,
		SCIP_HEUR *	heur,
		SCIP_RESULT *	result,
		SCIP_Real	minfixingrate,
		SCIP_Real	minimprove,
		SCIP_Longint	maxnodes,
		SCIP_Longint	nstallnodes,
		char	startsol,
		SCIP_Bool	binarybounds,
		SCIP_Bool	uselprows
	)

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

Parameters

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?