Scippy

SCIP

Solving Constraint Integer Programs

branch_pscost.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_pscost.h
17  * @ingroup BRANCHINGRULES
18  * @brief pseudo costs branching rule
19  * @author Tobias Achterberg
20  *
21  * The pseudo costs branching rule selects the branching variable with respect to the so-called pseudo costs
22  * of the variables. Pseudo costs measure the average gain per unit in the objective function when the variable
23  * was branched on upwards or downwards, resp. The required information is updated at every node of
24  * the solving process.
25  *
26  * The selected variable maximizes the expected gain of the dual bound in the created subtree.
27  *
28  * For a more mathematical description and a comparison between the pseudo costs branching rule
29  * and other branching rules 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 /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/
38 
39 #ifndef __SCIP_BRANCH_PSCOST_H__
40 #define __SCIP_BRANCH_PSCOST_H__
41 
42 
43 #include "scip/scip.h"
44 
45 #ifdef __cplusplus
46 extern "C" {
47 #endif
48 
49 /** creates the pseudo cost branching rule and includes it in SCIP */
50 extern
52  SCIP* scip /**< SCIP data structure */
53  );
54 
55 /** selects a branching variable, due to pseudo cost, from the given candidate array and returns this variable together
56  * with a branching point */
57 extern
59  SCIP* scip, /**< SCIP data structure */
60  SCIP_VAR** branchcands, /**< branching candidates */
61  SCIP_Real* branchcandssol, /**< solution value for the branching candidates */
62  SCIP_Real* branchcandsscore, /**< array of candidate scores */
63  int nbranchcands, /**< number of branching candidates */
64  SCIP_VAR** var, /**< pointer to store the variable to branch on, or NULL if none */
65  SCIP_Real* brpoint /**< pointer to store the branching point for the branching variable, will be fractional for a discrete variable */
66  );
67 
68 #ifdef __cplusplus
69 }
70 #endif
71 
72 #endif
73