Scippy

SCIP

Solving Constraint Integer Programs

branch_fullstrong.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) 2002-2017 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 branch_fullstrong.h
17  * @ingroup BRANCHINGRULES
18  * @brief full strong LP branching rule
19  * @author Tobias Achterberg
20  *
21  * The full strong branching rule applies strong branching to every fractional variable of the LP solution
22  * at the current node of the branch-and-bound search. The rule selects the candidate
23  * which will cause the highest gain of the dual bound in the created sub-tree among all branching variables.
24  *
25  * For calculating the gain, a look-ahead is performed by solving the child node LPs which will result
26  * from branching on a variable.
27  *
28  * For a more mathematical description and a comparison between the strong branching rule and other branching rules
29  * in SCIP, we refer to
30  *
31  * @par
32  * Tobias Achterberg@n
33  * Constraint Integer Programming@n
34  * PhD Thesis, Technische Universität Berlin, 2007@n
35  *
36  *
37  */
38 
39 /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/
40 
41 #ifndef __SCIP_BRANCH_FULLSTRONG_H__
42 #define __SCIP_BRANCH_FULLSTRONG_H__
43 
44 
45 #include "scip/scip.h"
46 
47 #ifdef __cplusplus
48 extern "C" {
49 #endif
50 
51 /** creates the full strong LP branching rule and includes it in SCIP
52  *
53  * @ingroup BranchingRuleIncludes
54  */
55 extern
57  SCIP* scip /**< SCIP data structure */
58  );
59 
60 /**@addtogroup BRANCHINGRULES
61  *
62  * @{
63  */
64 
65 /**
66  * Selects a variable from a set of candidates by strong branching
67  *
68  * @return \ref SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See \ref
69  * SCIP_Retcode "SCIP_RETCODE" for a complete list of error codes.
70  *
71  * @note The variables in the lpcands array must have a fractional value in the current LP solution
72  */
73 extern
75  SCIP* scip, /**< original SCIP data structure */
76  SCIP_VAR** lpcands, /**< branching candidates */
77  SCIP_Real* lpcandssol, /**< solution values of the branching candidates */
78  SCIP_Real* lpcandsfrac, /**< fractional values of the branching candidates */
79  SCIP_Bool* skipdown, /**< should down branchings be skipped? */
80  SCIP_Bool* skipup, /**< should up branchings be skipped? */
81  int nlpcands, /**< number of branching candidates */
82  int npriolpcands, /**< number of priority branching candidates */
83  int ncomplete, /**< number of branching candidates without skip */
84  int* start, /**< starting index in lpcands */
85  SCIP_Bool allowaddcons, /**< is the branching rule allowed to add constraints? */
86  int maxproprounds, /**< maximum number of propagation rounds to be performed during strong
87  * branching before solving the LP (-1: no limit, -2: parameter settings) */
88  SCIP_Bool probingbounds, /**< should valid bounds be identified in a probing-like fashion during
89  * strong branching (only with propagation)? */
90  SCIP_Bool forcestrongbranch, /**< should strong branching be applied even if there is just a single candidate? */
91  int* bestcand, /**< best candidate for branching */
92  SCIP_Real* bestdown, /**< objective value of the down branch for bestcand */
93  SCIP_Real* bestup, /**< objective value of the up branch for bestcand */
94  SCIP_Real* bestscore, /**< score for bestcand */
95  SCIP_Bool* bestdownvalid, /**< is bestdown a valid dual bound for the down branch? */
96  SCIP_Bool* bestupvalid, /**< is bestup a valid dual bound for the up branch? */
97  SCIP_Real* provedbound, /**< proved dual bound for current subtree */
98  SCIP_RESULT* result /**< result pointer */
99  );
100 
101 /* @} */
102 
103 #ifdef __cplusplus
104 }
105 #endif
106 
107 #endif
enum SCIP_Result SCIP_RESULT
Definition: type_result.h:52
enum SCIP_Retcode SCIP_RETCODE
Definition: type_retcode.h:53
#define SCIP_Bool
Definition: def.h:61
SCIP_RETCODE SCIPincludeBranchruleFullstrong(SCIP *scip)
SCIP_RETCODE SCIPselectVarStrongBranching(SCIP *scip, SCIP_VAR **lpcands, SCIP_Real *lpcandssol, SCIP_Real *lpcandsfrac, SCIP_Bool *skipdown, SCIP_Bool *skipup, int nlpcands, int npriolpcands, int ncomplete, int *start, SCIP_Bool allowaddcons, int maxproprounds, SCIP_Bool probingbounds, SCIP_Bool forcestrongbranch, int *bestcand, SCIP_Real *bestdown, SCIP_Real *bestup, SCIP_Real *bestscore, SCIP_Bool *bestdownvalid, SCIP_Bool *bestupvalid, SCIP_Real *provedbound, SCIP_RESULT *result)
#define SCIP_Real
Definition: def.h:135
SCIP callable library.