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) 2002-2014 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 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/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 extern
54  SCIP* scip /**< SCIP data structure */
55  );
56 
57 /**
58  * Selects a variable from a set of candidates by strong branching
59  *
60  * @return \ref SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See \ref
61  * SCIP_Retcode "SCIP_RETCODE" for a complete list of error codes.
62  *
63  * @note The variables in the lpcands array must have a fractional value in the current LP solution
64  */
65 extern
67  SCIP* scip, /**< original SCIP data structure */
68  SCIP_VAR** lpcands, /**< branching candidates */
69  SCIP_Real* lpcandssol, /**< solution values of the branching candidates */
70  SCIP_Real* lpcandsfrac, /**< fractional values of the branching candidates */
71  SCIP_Bool* skipdown, /**< should down branchings be skipped? */
72  SCIP_Bool* skipup, /**< should up branchings be skipped? */
73  int nlpcands, /**< number of branching candidates */
74  int npriolpcands, /**< number of priority branching candidates */
75  int ncomplete, /**< number of branching candidates without skip */
76  int* start, /**< starting index in lpcands */
77  SCIP_Bool allowaddcons, /**< is the branching rule allowed to add constraints? */
78  int maxproprounds, /**< maximum number of propagation rounds to be performed during strong
79  * branching before solving the LP (-1: no limit, -2: parameter settings) */
80  SCIP_Bool probingbounds, /**< should valid bounds be identified in a probing-like fashion during
81  * strong branching (only with propagation)? */
82  int* bestcand, /**< best candidate for branching */
83  SCIP_Real* bestdown, /**< objective value of the down branch for bestcand */
84  SCIP_Real* bestup, /**< objective value of the up branch for bestcand */
85  SCIP_Real* bestscore, /**< score for bestcand */
86  SCIP_Bool* bestdownvalid, /**< is bestdown a valid dual bound for the down branch? */
87  SCIP_Bool* bestupvalid, /**< is bestup a valid dual bound for the up branch? */
88  SCIP_Real* provedbound, /**< proved dual bound for current subtree */
89  SCIP_RESULT* result /**< result pointer */
90  );
91 
92 #ifdef __cplusplus
93 }
94 #endif
95 
96 #endif
97