Scippy

SCIP

Solving Constraint Integer Programs

cons_orbitope.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) 2002-2018 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 cons_orbitope.h
17  * @ingroup CONSHDLRS
18  * @brief constraint handler for (partitioning/packing/full) orbitope constraints w.r.t. the full symmetric group
19  * @author Timo Berthold
20  * @author Marc Pfetsch
21  * @author Christopher Hojny
22  */
23 
24 /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/
25 
26 #ifndef __SCIP_CONS_ORBITOPE_H__
27 #define __SCIP_CONS_ORBITOPE_H__
28 
29 #include "scip/scip.h"
30 
31 #ifdef __cplusplus
32 extern "C" {
33 #endif
34 
35 
36 /** creates the handler for orbitope constraints and includes it in SCIP
37  *
38  * @ingroup ConshdlrIncludes
39  */
40 extern
41 SCIP_RETCODE SCIPincludeConshdlrOrbitope(
42  SCIP* scip /**< SCIP data structure */
43  );
44 
45 /**@addtogroup CONSHDLRS
46  *
47  * @{
48  *
49  * @name Orbitope Constraints
50  *
51  * @{
52  *
53  * This constraint handler can be used to handle symmetries in certain 0/1-programs. The principle
54  * structure is that some variables can be ordered in matrix form, such that permuting columns does
55  * not change the validity and objective function value of a solution. That is, the symmetry group
56  * of the program contains the full symmetric group obtained by permuting the columns of this
57  * matrix. These symmetries can be handled by so-called full orbitopes.
58  *
59  * Moreover, if the variables in each row are contained in set packing or partitioning
60  * constraint, these symmetries can be handled by specialized packing or partitioning orbitopes.
61  *
62  * In more mathematical terms the structure has to be as follows: There are 0/1-variables
63  * \f$x_{ij}\f$, \f$i \in \{1, \dots, p\}\f$, \f$j \in \{1, \dots, q\}\f$. The variables may be coupled
64  * through set packing or partitioning constraints:
65  * \f[
66  * \sum_{j = 1}^q x_{ij} \leq 1 \quad \mbox{or} \quad \sum_{j = 1}^q x_{ij} = 1 \quad \mbox{for all }i = 1, \ldots, p.
67  * \f]
68  * Permuting columns of \f$x\f$ does not change the validity and objective function value of any feasible solution.
69  */
70 
71 /** type of orbitope constraint: full, packing, or partitioning orbitope */
72 enum SCIP_OrbitopeType
73 {
74  SCIP_ORBITOPETYPE_FULL = 0, /**< constraint is a full orbitope constraint: rowsum(x) unrestricted */
75  SCIP_ORBITOPETYPE_PARTITIONING = 1, /**< constraint is a partitioning orbitope constraint: rowsum(x) == 1 */
76  SCIP_ORBITOPETYPE_PACKING = 2 /**< constraint is a packing orbitope constraint: rowsum(x) <= 1 */
77 };
78 typedef enum SCIP_OrbitopeType SCIP_ORBITOPETYPE;
79 
80 /** creates and captures a orbitope constraint
81  *
82  * @note the constraint gets captured, hence at one point you have to release it using the method SCIPreleaseCons()
83  */
84 extern
85 SCIP_RETCODE SCIPcreateConsOrbitope(
86  SCIP* scip, /**< SCIP data structure */
87  SCIP_CONS** cons, /**< pointer to hold the created constraint */
88  const char* name, /**< name of constraint */
89  SCIP_VAR*** vars, /**< matrix of variables on which the symmetry acts */
90  SCIP_ORBITOPETYPE orbitopetype, /**< type of orbitope constraint */
91  int nspcons, /**< number of set partitioning/packing constraints <=> p */
92  int nblocks, /**< number of symmetric variable blocks <=> q */
93  SCIP_Bool resolveprop, /**< should propagation be resolved? */
94  SCIP_Bool initial, /**< should the LP relaxation of constraint be in the initial LP?
95  * Usually set to TRUE. Set to FALSE for 'lazy constraints'. */
96  SCIP_Bool separate, /**< should the constraint be separated during LP processing?
97  * Usually set to TRUE. */
98  SCIP_Bool enforce, /**< should the constraint be enforced during node processing?
99  * TRUE for model constraints, FALSE for additional, redundant constraints. */
100  SCIP_Bool check, /**< should the constraint be checked for feasibility?
101  * TRUE for model constraints, FALSE for additional, redundant constraints. */
102  SCIP_Bool propagate, /**< should the constraint be propagated during node processing?
103  * Usually set to TRUE. */
104  SCIP_Bool local, /**< is constraint only valid locally?
105  * Usually set to FALSE. Has to be set to TRUE, e.g., for branching constraints. */
106  SCIP_Bool modifiable, /**< is constraint modifiable (subject to column generation)?
107  * Usually set to FALSE. In column generation applications, set to TRUE if pricing
108  * adds coefficients to this constraint. */
109  SCIP_Bool dynamic, /**< is constraint subject to aging?
110  * Usually set to FALSE. Set to TRUE for own cuts which
111  * are separated as constraints. */
112  SCIP_Bool removable, /**< should the relaxation be removed from the LP due to aging or cleanup?
113  * Usually set to FALSE. Set to TRUE for 'lazy constraints' and 'user cuts'. */
114  SCIP_Bool stickingatnode /**< should the constraint always be kept at the node where it was added, even
115  * if it may be moved to a more global node?
116  * Usually set to FALSE. Set to TRUE to for constraints that represent node data. */
117  );
118 
119 /** creates and captures an orbitope constraint
120  * in its most basic variant, i. e., with all constraint flags set to their default values, which can be set
121  * afterwards using SCIPsetConsFLAGNAME() in scip.h
122  *
123  * @see SCIPcreateConsOrbitope() for the default constraint flag configuration
124  *
125  * @note the constraint gets captured, hence at one point you have to release it using the method SCIPreleaseCons()
126  */
127 extern
128 SCIP_RETCODE SCIPcreateConsBasicOrbitope(
129  SCIP* scip, /**< SCIP data structure */
130  SCIP_CONS** cons, /**< pointer to hold the created constraint */
131  const char* name, /**< name of constraint */
132  SCIP_VAR*** vars, /**< matrix of variables on which the symmetry acts */
133  SCIP_ORBITOPETYPE orbitopetype, /**< type of orbitope constraint */
134  int nspcons, /**< number of set partitioning/packing constraints <=> p */
135  int nblocks, /**< number of symmetric variable blocks <=> q */
136  SCIP_Bool resolveprop /**< should propagation be resolved? */
137  );
138 
139 /* @} */
140 
141 /* @} */
142 
143 #ifdef __cplusplus
144 }
145 #endif
146 
147 #endif
SCIPcreateConsOrbitope
SCIP_RETCODE SCIPcreateConsOrbitope(SCIP *scip, SCIP_CONS **cons, const char *name, SCIP_VAR ***vars, SCIP_ORBITOPETYPE orbitopetype, int nspcons, int nblocks, SCIP_Bool resolveprop, SCIP_Bool initial, SCIP_Bool separate, SCIP_Bool enforce, SCIP_Bool check, SCIP_Bool propagate, SCIP_Bool local, SCIP_Bool modifiable, SCIP_Bool dynamic, SCIP_Bool removable, SCIP_Bool stickingatnode)
Definition: cons_orbitope.c:3147
SCIP_Var
Definition: struct_var.h:198
SCIP_RETCODE
enum SCIP_Retcode SCIP_RETCODE
Definition: type_retcode.h:53
SCIPincludeConshdlrOrbitope
SCIP_RETCODE SCIPincludeConshdlrOrbitope(SCIP *scip)
Definition: cons_orbitope.c:3087
SCIP_Cons
Definition: struct_cons.h:37
SCIP_ORBITOPETYPE
enum SCIP_OrbitopeType SCIP_ORBITOPETYPE
Definition: cons_orbitope.h:78
SCIP_Bool
#define SCIP_Bool
Definition: def.h:61
SCIP_OrbitopeType
SCIP_OrbitopeType
Definition: cons_orbitope.h:72
SCIP_ORBITOPETYPE_PACKING
Definition: cons_orbitope.h:76
SCIP_ORBITOPETYPE_FULL
Definition: cons_orbitope.h:74
SCIPcreateConsBasicOrbitope
SCIP_RETCODE SCIPcreateConsBasicOrbitope(SCIP *scip, SCIP_CONS **cons, const char *name, SCIP_VAR ***vars, SCIP_ORBITOPETYPE orbitopetype, int nspcons, int nblocks, SCIP_Bool resolveprop)
Definition: cons_orbitope.c:3265
SCIP_ORBITOPETYPE_PARTITIONING
Definition: cons_orbitope.h:75
scip.h
SCIP callable library.