Scippy

SCIP

Solving Constraint Integer Programs

sepa_mcf.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 sepa_mcf.h
17  * @ingroup SEPARATORS
18  * @brief multi-commodity-flow network cut separator
19  * @author Tobias Achterberg
20  * @author Christian Raack
21  *
22  * We try to identify a multi-commodity flow structure in the LP relaxation of the
23  * following type:
24  *
25  * (1) sum_{a in delta^+(v)} f_a^k - sum_{a in delta^-(v)} f_a^k <= -d_v^k for all v in V and k in K
26  * (2) sum_{k in K} f_a^k - c_a x_a <= 0 for all a in A
27  *
28  * Constraints (1) are flow conservation constraints, which say that for each commodity k and node v the
29  * outflow (delta^+(v)) minus the inflow (delta^-(v)) of a node v must not exceed the negative of the demand of
30  * node v in commodity k. To say it the other way around, inflow minus outflow must be at least equal to the demand.
31  * Constraints (2) are the arc capacity constraints, which say that the sum of all flow over an arc a must not
32  * exceed its capacity c_a x_a, with x being a binary or integer variable.
33  * c_a x_a does not need to be a single product of a capacity and an integer variable; we also accept general scalar
34  * products.
35  */
36 
37 /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/
38 
39 #ifndef __SCIP_SEPA_MCF_H__
40 #define __SCIP_SEPA_MCF_H__
41 
42 #include "scip/scip.h"
43 
44 #ifdef __cplusplus
45 extern "C" {
46 #endif
47 
48 /** creates the mcf separator and includes it in SCIP */
49 extern
51  SCIP* scip /**< SCIP data structure */
52  );
53 
54 #ifdef __cplusplus
55 }
56 #endif
57 
58 #endif
59