Heur2opt.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) 2002-2022 Konrad-Zuse-Zentrum                            */
/*                            fuer Informationstechnik Berlin                */
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/**@file   Heur2opt.h
 * @brief  2-Optimum - combinatorial improvement heuristic for TSP
 * @author Timo Berthold
 */

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

#ifndef __HEUR2OPT_H__
#define __HEUR2OPT_H__

#include "objscip/objscip.h"

namespace tsp
{

/** C++ wrapper */
class Heur2opt : public scip::ObjHeur
{
   GRAPH*                graph_;             /**< the underlying graph of the TSP */
   int                   ncalls_;            /**< number of calls of the heuristic since the last solution was found */
   SCIP_SOL*             sol_;               /**< current solution */
   GRAPHEDGE**           tour_;              /**< tour induced by sol */

public:

   /** default constructor */
   Heur2opt(
      SCIP* scip
      )
      : ObjHeur(scip, "2opt", "2-Opt heuristic for TSPs", 'K',-1000000, 1, 0, -1, SCIP_HEURTIMING_AFTERNODE, FALSE),
      graph_(0),
      ncalls_(0),
      sol_(NULL),
      tour_(NULL)
   {
   }

   /** destructor */
   virtual ~Heur2opt()
   {
   } /*lint !e1540*/

   /** destructor of primal heuristic to free user data (called when SCIP is exiting) */
   virtual SCIP_DECL_HEURFREE(scip_free);

   /** initialization method of primal heuristic (called after problem was transformed) */
   virtual SCIP_DECL_HEURINIT(scip_init);

   /** deinitialization method of primal heuristic (called before transformed problem is freed) */
   virtual SCIP_DECL_HEUREXIT(scip_exit);

   /** solving process initialization method of primal heuristic (called when branch and bound process is about to begin)
    *
    *  This method is called when the presolving was finished and the branch and bound process is about to begin.
    *  The primal heuristic may use this call to initialize its branch and bound specific data.
    *
    */
   virtual SCIP_DECL_HEURINITSOL(scip_initsol);

   /** solving process deinitialization method of primal heuristic (called before branch and bound process data is freed)
    *
    *  This method is called before the branch and bound process is freed.
    *  The primal heuristic should use this call to clean up its branch and bound data.
    */
   virtual SCIP_DECL_HEUREXITSOL(scip_exitsol);

   /** execution method of primal heuristic
    *
    *  Searches for feasible primal solutions. The method is called in the node processing loop.
    *
    *  possible return values for *result:
    *  - SCIP_FOUNDSOL   : at least one feasible primal solution was found
    *  - SCIP_DIDNOTFIND : the heuristic searched, but did not find a feasible solution
    *  - SCIP_DIDNOTRUN  : the heuristic was skipped
    *  - SCIP_DELAYED    : the heuristic was skipped, but should be called again as soon as possible, disregarding
    *                      its frequency
    */
   virtual SCIP_DECL_HEUREXEC(scip_exec);

   /** clone method which will be used to copy a objective plugin */
   virtual SCIP_DECL_HEURCLONE(ObjCloneable* clone); /*lint !e665*/

   /** returns whether the objective plugin is copyable */
   virtual SCIP_DECL_HEURISCLONEABLE(iscloneable)
   {
      return TRUE;
   }
}; /*lint !e1712*/

}

#endif