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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 heur_twoopt.h
* @ingroup PRIMALHEURISTICS
* @brief Primal heuristic to improve incumbent solution by flipping pairs of variables
* @author Timo Berthold
* @author Gregor Hendel
*
* The Twoopt heuristic attempts to improve a feasible MIP solution by altering the solution values of pairs of
* variables. Only variables which share a pre-defined ratio of LP rows are considered as pairs. Each step of the
* heuristic consists of improving the objective value by shifting one variable, and then compensating the resulting
* infeasibilities by shifting a second variable, without completely losing the objective improvement. Similarly to
* Oneopt (see @ref heur_oneopt.h), pairs are processed in non-decreasing order of their impact on the objective.
*/
/*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/
#ifndef __SCIP_HEUR_TWOOPT_H__
#define __SCIP_HEUR_TWOOPT_H__
#include "scip/def.h"
#include "scip/type_retcode.h"
#include "scip/type_scip.h"
#ifdef __cplusplus
extern "C" {
#endif
/** creates the twoopt primal heuristic and includes it in SCIP
*
* @ingroup PrimalHeuristicIncludes
*/
SCIP_EXPORT
SCIP_RETCODE SCIPincludeHeurTwoopt(
SCIP* scip /**< SCIP data structure */
);
#ifdef __cplusplus
}
#endif
#endif