Scippy

SCIP

Solving Constraint Integer Programs

cons_orbitope.h
Go to the documentation of this file.
1 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
2 /* */
3 /* This file is part of the program and library */
4 /* SCIP --- Solving Constraint Integer Programs */
5 /* */
6 /* Copyright 2002-2022 Zuse Institute Berlin */
7 /* */
8 /* Licensed under the Apache License, Version 2.0 (the "License"); */
9 /* you may not use this file except in compliance with the License. */
10 /* You may obtain a copy of the License at */
11 /* */
12 /* http://www.apache.org/licenses/LICENSE-2.0 */
13 /* */
14 /* Unless required by applicable law or agreed to in writing, software */
15 /* distributed under the License is distributed on an "AS IS" BASIS, */
16 /* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. */
17 /* See the License for the specific language governing permissions and */
18 /* limitations under the License. */
19 /* */
20 /* You should have received a copy of the Apache-2.0 license */
21 /* along with SCIP; see the file LICENSE. If not visit scipopt.org. */
22 /* */
23 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
24 
25 /**@file cons_orbitope.h
26  * @ingroup CONSHDLRS
27  * @brief constraint handler for (partitioning/packing/full) orbitope constraints w.r.t. the full symmetric group
28  * @author Timo Berthold
29  * @author Marc Pfetsch
30  * @author Christopher Hojny
31  */
32 
33 /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/
34 
35 #ifndef __SCIP_CONS_ORBITOPE_H__
36 #define __SCIP_CONS_ORBITOPE_H__
37 
38 #include "scip/def.h"
39 #include "scip/type_cons.h"
40 #include "scip/type_retcode.h"
41 #include "scip/type_scip.h"
42 #include "scip/type_var.h"
43 #include "symmetry/type_symmetry.h"
44 
45 #ifdef __cplusplus
46 extern "C" {
47 #endif
48 
49 /** creates the handler for orbitope constraints and includes it in SCIP
50  *
51  * @ingroup ConshdlrIncludes
52  */
53 SCIP_EXPORT
55  SCIP* scip /**< SCIP data structure */
56  );
57 
58 /**@addtogroup CONSHDLRS
59  *
60  * @{
61  *
62  * @name Orbitope Constraints
63  *
64  * @{
65  *
66  * This constraint handler can be used to handle symmetries in certain 0/1-programs. The principle
67  * structure is that some variables can be ordered in matrix form, such that permuting columns does
68  * not change the validity and objective function value of a solution. That is, the symmetry group
69  * of the program contains the full symmetric group obtained by permuting the columns of this
70  * matrix. These symmetries can be handled by so-called full orbitopes.
71  *
72  * Moreover, if the variables in each row are contained in set packing or partitioning
73  * constraint, these symmetries can be handled by specialized packing or partitioning orbitopes.
74  *
75  * In more mathematical terms the structure has to be as follows: There are 0/1-variables
76  * \f$x_{ij}\f$, \f$i \in \{1, \dots, p\}\f$, \f$j \in \{1, \dots, q\}\f$. The variables may be coupled
77  * through set packing or partitioning constraints:
78  * \f[
79  * \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.
80  * \f]
81  * Permuting columns of \f$x\f$ does not change the validity and objective function value of any feasible solution.
82  *
83  * We distinguish whether an orbitope is a model constraint or not. If it is a model constraint, then
84  * its information are copied to subSCIPs. Otherwise, the constraint was added just for the purpose of
85  * symmetry handling and we do not copy its information to subSCIPs.
86  */
87 
88 /** creates and captures a orbitope constraint
89  *
90  * @note the constraint gets captured, hence at one point you have to release it using the method SCIPreleaseCons()
91  */
92 SCIP_EXPORT
94  SCIP* scip, /**< SCIP data structure */
95  SCIP_CONS** cons, /**< pointer to hold the created constraint */
96  const char* name, /**< name of constraint */
97  SCIP_VAR*** vars, /**< matrix of variables on which the symmetry acts */
98  SCIP_ORBITOPETYPE orbitopetype, /**< type of orbitope constraint */
99  int nspcons, /**< number of set partitioning/packing constraints <=> p */
100  int nblocks, /**< number of symmetric variable blocks <=> q */
101  SCIP_Bool usedynamicprop, /**< whether dynamic propagation should be used */
102  SCIP_Bool mayinteract, /**< whether symmetries corresponding to orbitope might interact
103  * with symmetries handled by other routines */
104  SCIP_Bool resolveprop, /**< should propagation be resolved? */
105  SCIP_Bool ismodelcons, /**< whether the orbitope is a model constraint */
106  SCIP_Bool initial, /**< should the LP relaxation of constraint be in the initial LP?
107  * Usually set to TRUE. Set to FALSE for 'lazy constraints'. */
108  SCIP_Bool separate, /**< should the constraint be separated during LP processing?
109  * Usually set to TRUE. */
110  SCIP_Bool enforce, /**< should the constraint be enforced during node processing?
111  * TRUE for model constraints, FALSE for additional, redundant constraints. */
112  SCIP_Bool check, /**< should the constraint be checked for feasibility?
113  * TRUE for model constraints, FALSE for additional, redundant constraints. */
114  SCIP_Bool propagate, /**< should the constraint be propagated during node processing?
115  * Usually set to TRUE. */
116  SCIP_Bool local, /**< is constraint only valid locally?
117  * Usually set to FALSE. Has to be set to TRUE, e.g., for branching constraints. */
118  SCIP_Bool modifiable, /**< is constraint modifiable (subject to column generation)?
119  * Usually set to FALSE. In column generation applications, set to TRUE if pricing
120  * adds coefficients to this constraint. */
121  SCIP_Bool dynamic, /**< is constraint subject to aging?
122  * Usually set to FALSE. Set to TRUE for own cuts which
123  * are separated as constraints. */
124  SCIP_Bool removable, /**< should the relaxation be removed from the LP due to aging or cleanup?
125  * Usually set to FALSE. Set to TRUE for 'lazy constraints' and 'user cuts'. */
126  SCIP_Bool stickingatnode /**< should the constraint always be kept at the node where it was added, even
127  * if it may be moved to a more global node?
128  * Usually set to FALSE. Set to TRUE to for constraints that represent node data. */
129  );
130 
131 /** creates and captures an orbitope constraint
132  * in its most basic variant, i. e., with all constraint flags set to their default values, which can be set
133  * afterwards using SCIPsetConsFLAGNAME() in scip.h
134  *
135  * @see SCIPcreateConsOrbitope() for the default constraint flag configuration
136  *
137  * @note the constraint gets captured, hence at one point you have to release it using the method SCIPreleaseCons()
138  */
139 SCIP_EXPORT
141  SCIP* scip, /**< SCIP data structure */
142  SCIP_CONS** cons, /**< pointer to hold the created constraint */
143  const char* name, /**< name of constraint */
144  SCIP_VAR*** vars, /**< matrix of variables on which the symmetry acts */
145  SCIP_ORBITOPETYPE orbitopetype, /**< type of orbitope constraint */
146  int nspcons, /**< number of set partitioning/packing constraints <=> p */
147  int nblocks, /**< number of symmetric variable blocks <=> q */
148  SCIP_Bool usedynamicprop, /**< whether dynamic propagation should be used */
149  SCIP_Bool resolveprop, /**< should propagation be resolved? */
150  SCIP_Bool ismodelcons, /**< whether the orbitope is a model constraint */
151  SCIP_Bool mayinteract /**< whether symmetries corresponding to orbitope might interact
152  * with symmetries handled by other routines */
153  );
154 
155 /** @} */
156 
157 /** @} */
158 
159 #ifdef __cplusplus
160 }
161 #endif
162 
163 #endif
enum SCIP_OrbitopeType SCIP_ORBITOPETYPE
SCIP_RETCODE SCIPcreateConsBasicOrbitope(SCIP *scip, SCIP_CONS **cons, const char *name, SCIP_VAR ***vars, SCIP_ORBITOPETYPE orbitopetype, int nspcons, int nblocks, SCIP_Bool usedynamicprop, SCIP_Bool resolveprop, SCIP_Bool ismodelcons, SCIP_Bool mayinteract)
enum SCIP_Retcode SCIP_RETCODE
Definition: type_retcode.h:63
type definitions for return codes for SCIP methods
SCIP_RETCODE SCIPincludeConshdlrOrbitope(SCIP *scip)
type definitions for SCIP&#39;s main datastructure
type definitions for problem variables
#define SCIP_Bool
Definition: def.h:93
type definitions for symmetry computations
SCIP_RETCODE SCIPcreateConsOrbitope(SCIP *scip, SCIP_CONS **cons, const char *name, SCIP_VAR ***vars, SCIP_ORBITOPETYPE orbitopetype, int nspcons, int nblocks, SCIP_Bool usedynamicprop, SCIP_Bool mayinteract, SCIP_Bool resolveprop, SCIP_Bool ismodelcons, 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)
common defines and data types used in all packages of SCIP
type definitions for constraints and constraint handlers