presol_symbreak.h

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/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/*                                                                           */
/*                  This file is part of the program and library             */
/*         SCIP --- Solving Constraint Integer Programs                      */
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/*    Copyright (C) 2002-2019 Konrad-Zuse-Zentrum                            */
/*                            fuer Informationstechnik Berlin                */
/*                                                                           */
/*  SCIP is distributed under the terms of the ZIB Academic License.         */
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/*  You should have received a copy of the ZIB Academic License              */
/*  along with SCIP; see the file COPYING. If not visit scip.zib.de.         */
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/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/**@file   presol_symbreak.h
 * @ingroup PRESOLVERS
 * @brief  presolver for adding symmetry breaking constraints
 * @author Marc Pfetsch
 * @author Thomas Rehn
 */

/*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/

#ifndef __SCIP_PRESOL_SYMBREAK_H__
#define __SCIP_PRESOL_SYMBREAK_H__

#include "scip/def.h"
#include "scip/type_retcode.h"
#include "scip/type_scip.h"
#include "scip/type_var.h"

#ifdef __cplusplus
extern "C" {
#endif

/** creates the symmetry breaking presolver and includes it in SCIP */
SCIP_EXPORT
SCIP_RETCODE SCIPincludePresolSymbreak(
   SCIP*                 scip                /**< SCIP data structure */
   );

/** compute non-trivial orbits of symmetry group
 *
 *  The non-tivial orbits of the group action are stored in the array orbits of length npermvars. This array contains
 *  the indices of variables from the permvars array such that variables that are contained in the same orbit appear
 *  consecutively in the orbits array. The variables of the i-th orbit have indices
 *  orbits[orbitbegins[i]], ... , orbits[orbitbegins[i + 1] - 1].
 *  Note that the description of the orbits ends at orbitbegins[norbits] - 1.
 */
SCIP_EXPORT
SCIP_RETCODE SCIPcomputeGroupOrbitsSymbreak(
   SCIP*                 scip,               /**< SCIP instance */
   SCIP_VAR**            permvars,           /**< variables considered by symbreak presolver */
   int                   npermvars,          /**< length of a permutation array */
   int**                 perms,              /**< matrix containing in each row a permutation of the symmetry group */
   int                   nperms,             /**< number of permutations encoded in perms */
   SCIP_Shortbool*       activeperms,        /**< array for marking active permutations (or NULL) */
   int*                  orbits,             /**< array of non-trivial orbits */
   int*                  orbitbegins,        /**< array containing begin positions of new orbits in orbits array */
   int*                  norbits             /**< pointer to number of orbits currently stored in orbits */
   );

#ifdef __cplusplus
}
#endif

#endif