Heur2opt.h

Go to the documentation of this file.

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/*                                                                           */
/*                  This file is part of the program and library             */
/*         SCIP --- Solving Constraint Integer Programs                      */
/*                                                                           */
/*  Copyright (c) 2002-2025 Zuse Institute Berlin (ZIB)                      */
/*                                                                           */
/*  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   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 /*lint --e{3713}*/
{
   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