1  #region License Information


2  /* HeuristicLab


3  * Copyright (C) 20022015 Heuristic and Evolutionary Algorithms Laboratory (HEAL)


4  *


5  * This file is part of HeuristicLab.


6  *


7  * HeuristicLab is free software: you can redistribute it and/or modify


8  * it under the terms of the GNU General Public License as published by


9  * the Free Software Foundation, either version 3 of the License, or


10  * (at your option) any later version.


11  *


12  * HeuristicLab is distributed in the hope that it will be useful,


13  * but WITHOUT ANY WARRANTY; without even the implied warranty of


14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the


15  * GNU General Public License for more details.


16  *


17  * You should have received a copy of the GNU General Public License


18  * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.


19  */


20  #endregion


21 


22  using System;


23  using System.Collections.Generic;


24  using HeuristicLab.Common;


25  using HeuristicLab.Core;


26  using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;


27 


28  namespace HeuristicLab.Encodings.LinearLinkageEncoding {


29  [Item("Group Crossover", "The Group Crossover is implemented as described in Korkmaz, E.E. 2010. Multiobjective Genetic Algorithms for grouping problems. Applied Intelligence 33(2), pp. 179192.")]


30  [StorableClass]


31  public sealed class GroupCrossover : LinearLinkageCrossover {


32 


33  [StorableConstructor]


34  private GroupCrossover(bool deserializing) : base(deserializing) { }


35  private GroupCrossover(GroupCrossover original, Cloner cloner) : base(original, cloner) { }


36  public GroupCrossover() { }


37 


38  public override IDeepCloneable Clone(Cloner cloner) {


39  return new GroupCrossover(this, cloner);


40  }


41 


42  public static LinearLinkage Apply(IRandom random, LinearLinkage p1, LinearLinkage p2) {


43  var length = p1.Length;


44  var child = new LinearLinkage(length);


45  var endNodes = new HashSet<int>();


46  for (var i = 0; i < length; i++) {


47  if ((p1[i] == i && p2[i] == i)


48   ((p1[i] == i  p2[i] == i) && random.NextDouble() < 0.5)) {


49  child[i] = i;


50  endNodes.Add(i);


51  }


52  }


53  for (var i = 0; i < length; i++) {


54  if (endNodes.Contains(i)) continue;


55  var p1End = endNodes.Contains(p1[i]);


56  var p2End = endNodes.Contains(p2[i]);


57  if ((p1End && p2End)  (!p1End && !p2End)) {


58  child[i] = random.NextDouble() < 0.5 ? p1[i] : p2[i];


59  } else if (p1End) {


60  child[i] = p1[i];


61  } else {


62  child[i] = p2[i];


63  }


64  }


65  child.LinearizeTreeStructures();


66  return child;


67  }


68 


69  protected override LinearLinkage Cross(IRandom random, ItemArray<LinearLinkage> parents) {


70  if (parents.Length != 2) throw new InvalidOperationException(Name + ": Can only cross exactly two parents.");


71  return Apply(random, parents[0], parents[1]);


72  }


73  }


74  }

