# SCIP

Solving Constraint Integer Programs

presol_implics.h
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1 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
2 /* */
3 /* This file is part of the program and library */
4 /* SCIP --- Solving Constraint Integer Programs */
5 /* */
7 /* fuer Informationstechnik Berlin */
8 /* */
10 /* */
12 /* along with SCIP; see the file COPYING. If not visit scipopt.org. */
13 /* */
14 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
15
16 /**@file presol_implics.h
17  * @ingroup PRESOLVERS
18  * @brief implication graph presolver which checks for aggregations
19  * @author Tobias Achterberg
20  *
21  * This presolver looks for variable implications in \f$x == 0\f$ and \f$x == 1\f$ with the same implied variable.
22  * There are four possible cases:
23  * \f[
24  * x = 0 \Rightarrow y = lb,\; \mathrm{and}\; x = 1 \Rightarrow y = lb:\; \mathrm{fix}\; y\; \mathrm{to}\; lb
25  * \f]
26  * \f[
27  * x = 0 \Rightarrow y = lb,\; \mathrm{and}\; x = 1 \Rightarrow y = ub:\; \mathrm{aggregate}\; y == lb + (ub-lb)x
28  * \f]
29  * \f[
30  * x = 0 \Rightarrow y = ub,\; \mathrm{and}\; x = 1 \Rightarrow y = lb:\; \mathrm{aggregate}\; y == ub - (ub-lb)x
31  * \f]
32  * \f[
33  * x = 0 \Rightarrow y = ub,\; \mathrm{and}\; x = 1 \Rightarrow y = ub:\; \mathrm{fix}\; y\; \mathrm{to}\; ub
34  * \f]
35  */
36
37 /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/
38
39 #ifndef __SCIP_PRESOL_IMPLICS_H__
40 #define __SCIP_PRESOL_IMPLICS_H__
41
42 #include "scip/def.h"
43 #include "scip/type_retcode.h"
44 #include "scip/type_scip.h"
45
46 #ifdef __cplusplus
47 extern "C" {
48 #endif
49
50 /** creates the implics presolver and includes it in SCIP
51  *
52  * @ingroup PresolverIncludes
53  */
56  SCIP* scip /**< SCIP data structure */
57  );
58
59 #ifdef __cplusplus
60 }
61 #endif
62
63 #endif
#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
SCIP_EXPORT SCIP_RETCODE SCIPincludePresolImplics(SCIP *scip)
common defines and data types used in all packages of SCIP