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source: branches/Scheduling/HeuristicLab.Encodings.RealVectorEncoding/3.3/Crossovers/SinglePointCrossover.cs @ 6319

Last change on this file since 6319 was 5445, checked in by swagner, 14 years ago

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1#region License Information
2/* HeuristicLab
3 * Copyright (C) 2002-2011 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
22using System;
23using HeuristicLab.Common;
24using HeuristicLab.Core;
25using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
26
27namespace 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,N-1) 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, Spring-Verlag 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, Spring-Verlag 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,N-1) 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}
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