1  #region License Information


2  /* HeuristicLab


3  * Copyright (C) 20022013 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 HeuristicLab.Common;


24  using HeuristicLab.Core;


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


26 


27  namespace HeuristicLab.Encodings.RealVectorEncoding {


28  /// <summary>


29  /// Single point crossover for real vectors. The implementation is similar to the single point crossover for binary vectors.


30  /// After a breakpoint is randomly chosen in the interval [1,N1) with N = length of the vector, the first part is copied from parent1 the other part copied from parent2.


31  /// The interval is chosen such that at least one position is taken from a different parent.


32  /// </summary>


33  /// <remarks>


34  /// It is implemented as described in Michalewicz, Z. 1999. Genetic Algorithms + Data Structures = Evolution Programs. Third, Revised and Extended Edition, SpringVerlag Berlin Heidelberg.


35  /// </remarks>


36  [Item("SinglePointCrossover", "Breaks both parent chromosomes at a randomly chosen point and assembles a child by taking one part of the first parent and the other part of the second pard. It is implemented as described in Michalewicz, Z. 1999. Genetic Algorithms + Data Structures = Evolution Programs. Third, Revised and Extended Edition, SpringVerlag Berlin Heidelberg.")]


37  [StorableClass]


38  public class SinglePointCrossover : RealVectorCrossover {


39  [StorableConstructor]


40  protected SinglePointCrossover(bool deserializing) : base(deserializing) { }


41  protected SinglePointCrossover(SinglePointCrossover original, Cloner cloner) : base(original, cloner) { }


42  public SinglePointCrossover() : base() { }


43 


44  public override IDeepCloneable Clone(Cloner cloner) {


45  return new SinglePointCrossover(this, cloner);


46  }


47 


48  /// <summary>


49  /// Performs the single point crossover for real vectors. The implementation is similar to the single point crossover for binary vectors.


50  /// After a breakpoint is randomly chosen in the interval [1,N1) with N = length of the vector, the first part is copied from parent1 the other part copied from parent2.


51  /// </summary>


52  /// <exception cref="ArgumentException">Thrown when the length of the vector is not the same in both parents.</exception>


53  /// <param name="random">A random number generator.</param>


54  /// <param name="parent1">The first parent for crossover.</param>


55  /// <param name="parent2">The second parent for crossover.</param>


56  /// <returns>The newly created real vector, resulting from the single point crossover.</returns>


57  public static RealVector Apply(IRandom random, RealVector parent1, RealVector parent2) {


58  if (parent1.Length != parent2.Length) throw new ArgumentException("SinglePointCrossover: Parents are of unequal length");


59  if (parent1.Length < 2) throw new ArgumentException("SinglePointCrossover: Cannot be applied to vectors with just one dimension.");


60  int length = parent1.Length;


61  RealVector result = new RealVector(length);


62  int breakPoint;


63  if (length == 2) breakPoint = 1;


64  else breakPoint = random.Next(1, length  1);


65 


66  for (int i = 0; i < breakPoint; i++)


67  result[i] = parent1[i];


68  for (int i = breakPoint; i < length; i++)


69  result[i] = parent2[i];


70 


71  return result;


72  }


73 


74  /// <summary>


75  /// Checks number of parents and forwards the call to <see cref="Apply(IRandom, RealVector, RealVector)"/>.


76  /// </summary>


77  /// <exception cref="ArgumentException">Thrown when the parents' vectors are of unequal length or when <paramref name="contiguity"/> is smaller than 0.</exception>


78  /// <param name="random">The pseudo random number generator to use.</param>


79  /// <param name="parents">The list of parents.</param>


80  /// <returns>A new real vector.</returns>


81  protected override RealVector Cross(IRandom random, ItemArray<RealVector> parents) {


82  if (parents.Length != 2) throw new ArgumentException("SinglePointCrossover: The number of parents is not equal to 2");


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


84  }


85  }


86  }

