source: branches/2520_PersistenceReintegration/HeuristicLab.Encodings.RealVectorEncoding/3.3/Crossovers/AverageCrossover.cs @ 16453

Last change on this file since 16453 was 16453, checked in by jkarder, 12 months ago

#2520: updated year of copyrights

File size: 3.9 KB
Line 
1#region License Information
2/* HeuristicLab
3 * Copyright (C) 2002-2019 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  /// The average crossover (intermediate recombination) calculates the average or centroid of a number of parent vectors.
30  /// </summary>
31  /// <remarks>
32  /// It is implemented as described by Beyer, H.-G. and Schwefel, H.-P. 2002. Evolution Strategies - A Comprehensive Introduction Natural Computing, 1, pp. 3-52.
33  /// </remarks>
34  [Item("AverageCrossover", "The average crossover (intermediate recombination) produces a new offspring by calculating in each position the average of a number of parents. It is implemented as described by Beyer, H.-G. and Schwefel, H.-P. 2002. Evolution Strategies - A Comprehensive Introduction Natural Computing, 1, pp. 3-52.")]
35  [StorableClass]
36  public class AverageCrossover : RealVectorCrossover {
37    [StorableConstructor]
38    protected AverageCrossover(bool deserializing) : base(deserializing) { }
39    protected AverageCrossover(AverageCrossover original, Cloner cloner) : base(original, cloner) { }
40    public AverageCrossover() : base() { }
41
42    public override IDeepCloneable Clone(Cloner cloner) {
43      return new AverageCrossover(this, cloner);
44    }
45   
46    /// <summary>
47    /// Performs the average crossover (intermediate recombination) on a list of parents.
48    /// </summary>
49    /// <exception cref="ArgumentException">Thrown when there is just one parent or when the parent vectors are of different length.</exception>
50    /// <remarks>
51    /// There can be more than two parents.
52    /// </remarks>
53    /// <param name="random">The random number generator.</param>
54    /// <param name="parents">The list of parents.</param>
55    /// <returns>The child vector (average) of the parents.</returns>
56    public static RealVector Apply(IRandom random, ItemArray<RealVector> parents) {
57      int length = parents[0].Length, parentsCount = parents.Length;
58      if (parents.Length < 2) throw new ArgumentException("AverageCrossover: The number of parents is less than 2.", "parents");
59      RealVector result = new RealVector(length);
60      try {
61        double avg;
62        for (int i = 0; i < length; i++) {
63          avg = 0;
64          for (int j = 0; j < parentsCount; j++)
65            avg += parents[j][i];
66          result[i] = avg / (double)parentsCount;
67        }
68      }
69      catch (IndexOutOfRangeException) {
70        throw new ArgumentException("AverageCrossover: The parents' vectors are of different length.", "parents");
71      }
72
73      return result;
74    }
75
76    /// <summary>
77    /// Forwards the call to <see cref="Apply(IRandom, ItemArray<RealVector>)"/>.
78    /// </summary>
79    /// <param name="random">The random number generator.</param>
80    /// <param name="parents">The list of parents.</param>
81    /// <returns>The child vector (average) of the parents.</returns>
82    protected override RealVector Cross(IRandom random, ItemArray<RealVector> parents) {
83      return Apply(random, parents);
84    }
85  }
86}
Note: See TracBrowser for help on using the repository browser.