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 2002-2022 Zuse Institute Berlin */
7 /* */
8 /* Licensed under the Apache License, Version 2.0 (the "License"); */
9 /* you may not use this file except in compliance with the License. */
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19 /* */
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21 /* along with SCIP; see the file LICENSE. If not visit scipopt.org. */
22 /* */
23 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
24 
25 /**@file heur_rens.h
26  * @ingroup PRIMALHEURISTICS
27  * @brief LNS heuristic that finds the optimal rounding to a given point
28  * @author Timo Berthold
29  *
30  * RENS is a large neighborhood search start heuristic, i.e., unlike other LNS heuristics, it does not need a known
31  * feasible solution. It solves a sub-SCIP that is created by fixing variables which take an integral value in a given
32  * LP or NLP solution. For the remaining integer variables, the bounds get tightened to the two nearest integral values.
33  */
34 
35 /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/
36 
37 #ifndef __SCIP_HEUR_RENS_H__
38 #define __SCIP_HEUR_RENS_H__
39 
40 #include "scip/def.h"
41 #include "scip/type_heur.h"
42 #include "scip/type_result.h"
43 #include "scip/type_retcode.h"
44 #include "scip/type_scip.h"
45 
46 #ifdef __cplusplus
47 extern "C" {
48 #endif
49 
50 /** creates RENS primal heuristic and includes it in SCIP
51  *
52  * @ingroup PrimalHeuristicIncludes
53  */
54 SCIP_EXPORT
56  SCIP* scip /**< SCIP data structure */
57  );
58 
59 /**@addtogroup PRIMALHEURISTICS
60  *
61  * @{
62  */
63 
64 /** main procedure of the RNS heuristic, creates and solves a sub-SCIP */
65 SCIP_EXPORT
67  SCIP* scip, /**< original SCIP data structure */
68  SCIP_HEUR* heur, /**< heuristic data structure */
69  SCIP_RESULT* result, /**< result data structure */
70  SCIP_Real minfixingrate, /**< minimum percentage of integer variables that have to be fixed */
71  SCIP_Real minimprove, /**< factor by which RENS should at least improve the incumbent */
72  SCIP_Longint maxnodes, /**< maximum number of nodes for the subproblem */
73  SCIP_Longint nstallnodes, /**< number of stalling nodes for the subproblem */
74  char startsol, /**< solution used for fixing values ('l'p relaxation, 'n'lp relaxation) */
75  SCIP_Bool binarybounds, /**< should general integers get binary bounds [floor(.),ceil(.)]? */
76  SCIP_Bool uselprows /**< should subproblem be created out of the rows in the LP rows? */
77  );
78 
79 /** @} */
80 
81 #ifdef __cplusplus
82 }
83 #endif
84 
85 #endif
enum SCIP_Result SCIP_RESULT
Definition: type_result.h:61
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)
Definition: heur_rens.c:603
enum SCIP_Retcode SCIP_RETCODE
Definition: type_retcode.h:63
type definitions for return codes for SCIP methods
SCIP_RETCODE SCIPincludeHeurRens(SCIP *scip)
Definition: heur_rens.c:819
type definitions for primal heuristics
type definitions for SCIP&#39;s main datastructure
#define SCIP_Bool
Definition: def.h:93
#define SCIP_Real
Definition: def.h:186
result codes for SCIP callback methods
#define SCIP_Longint
Definition: def.h:171
common defines and data types used in all packages of SCIP