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) 2002-2021 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 visit scipopt.org. */
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 Universit├Ąt 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/def.h"
46 #include "scip/type_result.h"
47 #include "scip/type_retcode.h"
48 #include "scip/type_scip.h"
49 #include "scip/type_var.h"
50 
51 #ifdef __cplusplus
52 extern "C" {
53 #endif
54 
55 /** creates the full strong LP branching rule and includes it in SCIP
56  *
57  * @ingroup BranchingRuleIncludes
58  */
61  SCIP* scip /**< SCIP data structure */
62  );
63 
64 /**@addtogroup BRANCHINGRULES
65  *
66  * @{
67  */
68 
69 /**
70  * Selects a variable from a set of candidates by strong branching
71  *
72  * @return \ref SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See \ref
73  * SCIP_Retcode "SCIP_RETCODE" for a complete list of error codes.
74  *
75  * @note The variables in the lpcands array must have a fractional value in the current LP solution
76  */
79  SCIP* scip, /**< original SCIP data structure */
80  SCIP_VAR** lpcands, /**< branching candidates */
81  SCIP_Real* lpcandssol, /**< solution values of the branching candidates */
82  SCIP_Real* lpcandsfrac, /**< fractional values of the branching candidates */
83  SCIP_Bool* skipdown, /**< should down branchings be skipped? */
84  SCIP_Bool* skipup, /**< should up branchings be skipped? */
85  int nlpcands, /**< number of branching candidates */
86  int npriolpcands, /**< number of priority branching candidates */
87  int ncomplete, /**< number of branching candidates without skip */
88  int* start, /**< starting index in lpcands */
89  int maxproprounds, /**< maximum number of propagation rounds to be performed during strong
90  * branching before solving the LP (-1: no limit, -2: parameter settings) */
91  SCIP_Bool probingbounds, /**< should valid bounds be identified in a probing-like fashion during
92  * strong branching (only with propagation)? */
93  SCIP_Bool forcestrongbranch, /**< should strong branching be applied even if there is just a single candidate? */
94  int* bestcand, /**< best candidate for branching */
95  SCIP_Real* bestdown, /**< objective value of the down branch for bestcand */
96  SCIP_Real* bestup, /**< objective value of the up branch for bestcand */
97  SCIP_Real* bestscore, /**< score for bestcand */
98  SCIP_Bool* bestdownvalid, /**< is bestdown a valid dual bound for the down branch? */
99  SCIP_Bool* bestupvalid, /**< is bestup a valid dual bound for the up branch? */
100  SCIP_Real* provedbound, /**< proved dual bound for current subtree */
101  SCIP_RESULT* result /**< result pointer */
102  );
103 
104 /** @} */
105 
106 #ifdef __cplusplus
107 }
108 #endif
109 
110 #endif
enum SCIP_Result SCIP_RESULT
Definition: type_result.h:52
SCIP_EXPORT 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, 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_EXPORT
Definition: def.h:100
enum SCIP_Retcode SCIP_RETCODE
Definition: type_retcode.h:54
type definitions for return codes for SCIP methods
type definitions for SCIP&#39;s main datastructure
type definitions for problem variables
SCIP_EXPORT SCIP_RETCODE SCIPincludeBranchruleFullstrong(SCIP *scip)
#define SCIP_Bool
Definition: def.h:70
#define SCIP_Real
Definition: def.h:163
result codes for SCIP callback methods
common defines and data types used in all packages of SCIP