Scippy

SCIP

Solving Constraint Integer Programs

heur_rens.h
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1 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
2 /* */
3 /* This file is part of the program and library */
4 /* SCIP --- Solving Constraint Integer Programs */
5 /* */
6 /* Copyright (C) 2002-2016 Konrad-Zuse-Zentrum */
7 /* fuer Informationstechnik Berlin */
8 /* */
9 /* SCIP is distributed under the terms of the ZIB Academic License. */
10 /* */
11 /* You should have received a copy of the ZIB Academic License */
12 /* along with SCIP; see the file COPYING. If not email to scip@zib.de. */
13 /* */
14 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
15 
16 /**@file heur_rens.h
17  * @ingroup PRIMALHEURISTICS
18  * @brief LNS heuristic that finds the optimal rounding to a given point
19  * @author Timo Berthold
20  *
21  * RENS is a large neighborhood search start heuristic, i.e., unlike other LNS heuristics, it does not need a known
22  * feasible solution. It solves a sub-SCIP that is created by fixing variables which take an integral value in a given
23  * LP or NLP solution. For the remaining integer variables, the bounds get tightened to the two nearest integral values.
24  */
25 
26 /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/
27 
28 #ifndef __SCIP_HEUR_RENS_H__
29 #define __SCIP_HEUR_RENS_H__
30 
31 #include "scip/scip.h"
32 
33 #ifdef __cplusplus
34 extern "C" {
35 #endif
36 
37 /** creates RENS primal heuristic and includes it in SCIP */
38 extern
40  SCIP* scip /**< SCIP data structure */
41  );
42 
43 /** main procedure of the RENS heuristic, creates and solves a sub-SCIP */
45  SCIP* scip, /**< original SCIP data structure */
46  SCIP_HEUR* heur, /**< heuristic data structure */
47  SCIP_RESULT* result, /**< result data structure */
48  SCIP_Real minfixingrate, /**< minimum percentage of integer variables that have to be fixed */
49  SCIP_Real minimprove, /**< factor by which RENS should at least improve the incumbent */
50  SCIP_Longint maxnodes, /**< maximum number of nodes for the subproblem */
51  SCIP_Longint nstallnodes, /**< number of stalling nodes for the subproblem */
52  char startsol, /**< solution used for fixing values ('l'p relaxation, 'n'lp relaxation) */
53  SCIP_Bool binarybounds, /**< should general integers get binary bounds [floor(.),ceil(.)]? */
54  SCIP_Bool uselprows /**< should subproblem be created out of the rows in the LP rows? */
55  );
56 
57 #ifdef __cplusplus
58 }
59 #endif
60 
61 #endif
enum SCIP_Result SCIP_RESULT
Definition: type_result.h:51
struct SCIP_Heur SCIP_HEUR
Definition: type_heur.h:50
enum SCIP_Retcode SCIP_RETCODE
Definition: type_retcode.h:53
struct Scip SCIP
Definition: type_scip.h:30
SCIP_RETCODE SCIPincludeHeurRens(SCIP *scip)
#define SCIP_Bool
Definition: def.h:53
#define SCIP_Real
Definition: def.h:127
#define SCIP_Longint
Definition: def.h:112
SCIP callable library.
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)