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/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/* */
/* This file is part of the program and library */
/* SCIP --- Solving Constraint Integer Programs */
/* */
/* Copyright 2002-2022 Zuse Institute Berlin */
/* */
/* Licensed under the Apache License, Version 2.0 (the "License"); */
/* you may not use this file except in compliance with the License. */
/* You may obtain a copy of the License at */
/* */
/* http://www.apache.org/licenses/LICENSE-2.0 */
/* */
/* Unless required by applicable law or agreed to in writing, software */
/* distributed under the License is distributed on an "AS IS" BASIS, */
/* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. */
/* See the License for the specific language governing permissions and */
/* limitations under the License. */
/* */
/* You should have received a copy of the Apache-2.0 license */
/* along with SCIP; see the file LICENSE. If not visit scipopt.org. */
/* */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/**@file cons_orbitope.h
* @ingroup CONSHDLRS
* @brief constraint handler for (partitioning/packing/full) orbitope constraints w.r.t. the full symmetric group
* @author Timo Berthold
* @author Marc Pfetsch
* @author Christopher Hojny
*/
/*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/
#ifndef __SCIP_CONS_ORBITOPE_H__
#define __SCIP_CONS_ORBITOPE_H__
#include "scip/def.h"
#include "scip/type_cons.h"
#include "scip/type_retcode.h"
#include "scip/type_scip.h"
#include "scip/type_var.h"
#include "symmetry/type_symmetry.h"
#ifdef __cplusplus
extern "C" {
#endif
/** creates the handler for orbitope constraints and includes it in SCIP
*
* @ingroup ConshdlrIncludes
*/
SCIP_EXPORT
SCIP_RETCODE SCIPincludeConshdlrOrbitope(
SCIP* scip /**< SCIP data structure */
);
/**@addtogroup CONSHDLRS
*
* @{
*
* @name Orbitope Constraints
*
* @{
*
* This constraint handler can be used to handle symmetries in certain 0/1-programs. The principle
* structure is that some variables can be ordered in matrix form, such that permuting columns does
* not change the validity and objective function value of a solution. That is, the symmetry group
* of the program contains the full symmetric group obtained by permuting the columns of this
* matrix. These symmetries can be handled by so-called full orbitopes.
*
* Moreover, if the variables in each row are contained in set packing or partitioning
* constraint, these symmetries can be handled by specialized packing or partitioning orbitopes.
*
* In more mathematical terms the structure has to be as follows: There are 0/1-variables
* \f$x_{ij}\f$, \f$i \in \{1, \dots, p\}\f$, \f$j \in \{1, \dots, q\}\f$. The variables may be coupled
* through set packing or partitioning constraints:
* \f[
* \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.
* \f]
* Permuting columns of \f$x\f$ does not change the validity and objective function value of any feasible solution.
*
* We distinguish whether an orbitope is a model constraint or not. If it is a model constraint, then
* its information are copied to subSCIPs. Otherwise, the constraint was added just for the purpose of
* symmetry handling and we do not copy its information to subSCIPs.
*/
/** creates and captures a orbitope constraint
*
* @note the constraint gets captured, hence at one point you have to release it using the method SCIPreleaseCons()
*/
SCIP_EXPORT
SCIP_RETCODE SCIPcreateConsOrbitope(
SCIP* scip, /**< SCIP data structure */
SCIP_CONS** cons, /**< pointer to hold the created constraint */
const char* name, /**< name of constraint */
SCIP_VAR*** vars, /**< matrix of variables on which the symmetry acts */
SCIP_ORBITOPETYPE orbitopetype, /**< type of orbitope constraint */
int nspcons, /**< number of set partitioning/packing constraints <=> p */
int nblocks, /**< number of symmetric variable blocks <=> q */
SCIP_Bool usedynamicprop, /**< whether dynamic propagation should be used */
SCIP_Bool mayinteract, /**< whether symmetries corresponding to orbitope might interact
* with symmetries handled by other routines */
SCIP_Bool resolveprop, /**< should propagation be resolved? */
SCIP_Bool ismodelcons, /**< whether the orbitope is a model constraint */
SCIP_Bool initial, /**< should the LP relaxation of constraint be in the initial LP?
* Usually set to TRUE. Set to FALSE for 'lazy constraints'. */
SCIP_Bool separate, /**< should the constraint be separated during LP processing?
* Usually set to TRUE. */
SCIP_Bool enforce, /**< should the constraint be enforced during node processing?
* TRUE for model constraints, FALSE for additional, redundant constraints. */
SCIP_Bool check, /**< should the constraint be checked for feasibility?
* TRUE for model constraints, FALSE for additional, redundant constraints. */
SCIP_Bool propagate, /**< should the constraint be propagated during node processing?
* Usually set to TRUE. */
SCIP_Bool local, /**< is constraint only valid locally?
* Usually set to FALSE. Has to be set to TRUE, e.g., for branching constraints. */
SCIP_Bool modifiable, /**< is constraint modifiable (subject to column generation)?
* Usually set to FALSE. In column generation applications, set to TRUE if pricing
* adds coefficients to this constraint. */
SCIP_Bool dynamic, /**< is constraint subject to aging?
* Usually set to FALSE. Set to TRUE for own cuts which
* are separated as constraints. */
SCIP_Bool removable, /**< should the relaxation be removed from the LP due to aging or cleanup?
* Usually set to FALSE. Set to TRUE for 'lazy constraints' and 'user cuts'. */
SCIP_Bool stickingatnode /**< should the constraint always be kept at the node where it was added, even
* if it may be moved to a more global node?
* Usually set to FALSE. Set to TRUE to for constraints that represent node data. */
);
/** creates and captures an orbitope constraint
* in its most basic variant, i. e., with all constraint flags set to their default values, which can be set
* afterwards using SCIPsetConsFLAGNAME() in scip.h
*
* @see SCIPcreateConsOrbitope() for the default constraint flag configuration
*
* @note the constraint gets captured, hence at one point you have to release it using the method SCIPreleaseCons()
*/
SCIP_EXPORT
SCIP_RETCODE SCIPcreateConsBasicOrbitope(
SCIP* scip, /**< SCIP data structure */
SCIP_CONS** cons, /**< pointer to hold the created constraint */
const char* name, /**< name of constraint */
SCIP_VAR*** vars, /**< matrix of variables on which the symmetry acts */
SCIP_ORBITOPETYPE orbitopetype, /**< type of orbitope constraint */
int nspcons, /**< number of set partitioning/packing constraints <=> p */
int nblocks, /**< number of symmetric variable blocks <=> q */
SCIP_Bool usedynamicprop, /**< whether dynamic propagation should be used */
SCIP_Bool resolveprop, /**< should propagation be resolved? */
SCIP_Bool ismodelcons, /**< whether the orbitope is a model constraint */
SCIP_Bool mayinteract /**< whether symmetries corresponding to orbitope might interact
* with symmetries handled by other routines */
);
/** @} */
/** @} */
#ifdef __cplusplus
}
#endif
#endif