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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 presol_gateextraction.h
* @ingroup PRESOLVERS
* @brief gateextraction presolver
* @author Michael Winkler
*/
/* This presolver tries to extract gate-constraints meaning and-constraints and set-partitioning constraints (and could
* be expanded to find xor-constraints too). This is done by detecting linearizations or systems of inequalities which
* form an and-constraint or a set-partitioning constraint. An example:
*
* we have a logicor constraint of the form: x + y + z >= 1
*
* and we also have the following set-packing constraints: (x + y <= 1 and x + z <= 1) <=> (~x + ~y >= 1 and ~x + ~z >= 1)
*
* - these three constraints form an and-constraint: x = ~y * ~z (x = AND(~y,~z))
*
* if an additional set-packing constraint exists: y + z <= 1
*
* - these four constraints form a set-partitioning cons.: x + y + z = 1
*
* some information can be found:
*
* http://www.cs.ubc.ca/~hutter/earg/papers07/cnf-structure.pdf
* http://www.cadence.com/cn/cadence/cadence_labs/Documents/niklas_SAT_2005_Effective.pdf
*
* We also do some check for logicor and set-packing/-partitioning constraint with the same variables to upgrade these
* both constraints into one. For example:
*
* x + y + z >= 1 and x + y + z <= 1 form x + y + z = 1
*
*/
/*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/
#ifndef __SCIP_PRESOL_GATEEXTRACTION_H__
#define __SCIP_PRESOL_GATEEXTRACTION_H__
#include "scip/def.h"
#include "scip/type_retcode.h"
#include "scip/type_scip.h"
#ifdef __cplusplus
extern "C" {
#endif
/** creates the gateextraction presolver and includes it in SCIP
*
* @ingroup PresolverIncludes
*/
SCIP_EXPORT
SCIP_RETCODE SCIPincludePresolGateextraction(
SCIP* scip /**< SCIP data structure */
);
#ifdef __cplusplus
}
#endif
#endif