heur_local.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) 2002-2015 Konrad-Zuse-Zentrum                            */
/*                            fuer Informationstechnik Berlin                */
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/*  SCIP is distributed under the terms of the ZIB Academic License.         */
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/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/**@file   heur_local.h
 * @brief  Improvement heuristic for Steiner problems
 * @author Daniel Rehfeldt
 *
 * This file implements three local heuristics, namely vertex insertion, key-path exchange and key-vertex elimination,
 * see "Fast Local Search for Steiner Trees in Graphs" by Uchoa and Werneck.
 *
 */

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

#ifndef __SCIP_HEUR_LOCAL_H__
#define __SCIP_HEUR_LOCAL_H__


#include "scip/scip.h"
#include "grph.h"
#ifdef __cplusplus
extern "C" {
#endif

/** creates the local primal heuristic and includes it in SCIP */
extern
SCIP_RETCODE SCIPincludeHeurLocal(
   SCIP*                 scip                /**< SCIP data structure */
   );

/** perform local heuristics on a given Steiner tree */
extern
SCIP_RETCODE SCIPheurImproveSteinerTree(
   SCIP*                 scip,               /**< SCIP data structure */
   GRAPH*                graph,              /**< graph data structure */
   SCIP_Real*            cost,               /**< arc cost array */
   SCIP_Real*            costrev,            /**< reversed arc cost array */
   int*                  best_result         /**< array indicating whether an arc is part of the solution (CONNECTED/UNKNOWN) */
   );

/** local heuristic for (R)PC and MW */
extern
SCIP_RETCODE extendSteinerTreePcMw(
   SCIP*                 scip,               /**< SCIP data structure */
   const GRAPH*          graph,              /**< graph data structure */
   PATH*                 vnoi,               /**< Voronoi data structure array */
   SCIP_Real*            costrev,            /**< reversed edge costs */
   int*                  vbase,              /**< array to store Voronoi bases to each vertex */
   int*                  stedge,             /**< array to indicate whether an edge is part of the Steiner tree */
   char*                 stvertex,           /**< uninitialized array to indicate whether an edge is part of the Steiner tree */
   int*                  adds                /**< pointer to store number of added vertices */
);

#ifdef __cplusplus
}
#endif

#endif