1 | #region License Information
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2 | /* HeuristicLab
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3 | * Copyright (C) 2002-2012 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
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4 | *
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5 | * This file is part of HeuristicLab.
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6 | *
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7 | * HeuristicLab is free software: you can redistribute it and/or modify
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8 | * it under the terms of the GNU General Public License as published by
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9 | * the Free Software Foundation, either version 3 of the License, or
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10 | * (at your option) any later version.
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11 | *
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12 | * HeuristicLab is distributed in the hope that it will be useful,
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13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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15 | * GNU General Public License for more details.
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16 | *
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17 | * You should have received a copy of the GNU General Public License
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18 | * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
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19 | */
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20 | #endregion
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21 |
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22 | using System;
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23 | using HeuristicLab.Common;
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24 | using HeuristicLab.Core;
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25 | using HeuristicLab.Data;
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26 | using HeuristicLab.Parameters;
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27 | using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
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28 |
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29 | namespace HeuristicLab.Encodings.IntegerVectorEncoding {
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30 | /// <summary>
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31 | /// Average crossover for integer vectors.
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32 | /// </summary>
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33 | [Item("AverageCrossover", "Average crossover for integer vectors.")]
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34 | [StorableClass]
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35 | public class AverageCrossover : IntegerVectorCrossover, IBoundedIntegerVectorOperator {
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36 |
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37 | public IValueLookupParameter<IntMatrix> BoundsParameter {
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38 | get { return (IValueLookupParameter<IntMatrix>)Parameters["Bounds"]; }
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39 | }
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40 |
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41 | [StorableConstructor]
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42 | protected AverageCrossover(bool deserializing) : base(deserializing) { }
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43 | protected AverageCrossover(AverageCrossover original, Cloner cloner) : base(original, cloner) { }
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44 | public AverageCrossover()
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45 | : base() {
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46 | Parameters.Add(new ValueLookupParameter<IntMatrix>("Bounds", "The bounds matrix can contain one row for each dimension with three columns specifying minimum (inclusive), maximum (exclusive), and step size. If less rows are given the matrix is cycled."));
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47 | }
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48 |
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49 | public override IDeepCloneable Clone(Cloner cloner) {
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50 | return new AverageCrossover(this, cloner);
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51 | }
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52 |
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53 | /// <summary>
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54 | /// Performs an average crossover of the two given parent integer vectors.
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55 | /// The average is rounded and mapped to the nearest valid value (e.g. if step size is > 1)
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56 | /// </summary>
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57 | /// <param name="random">A random number generator.</param>
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58 | /// <param name="parents">The parents for crossover.</param>
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59 | /// <param name="bounds">The bounds matrix that contains for each dimension one row with minimum (inclusive), maximum (exclusive), and step size columns.
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60 | /// If the number of rows is smaller than the number of dimensions the matrix is cycled.</param>
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61 | /// <returns>The newly created integer vector, resulting from the single point crossover.</returns>
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62 | public static IntegerVector Apply(IRandom random, ItemArray<IntegerVector> parents, IntMatrix bounds) {
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63 | int length = parents[0].Length, parentsCount = parents.Length;
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64 | if (parents.Length < 2) throw new ArgumentException("AverageCrossover: The number of parents is less than 2.", "parents");
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65 | if (bounds == null || bounds.Rows < 1 || bounds.Columns < 2) throw new ArgumentException("AverageCrossover: Invalid bounds specified.", "bounds");
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66 |
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67 | var result = new IntegerVector(length);
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68 | try {
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69 | double avg;
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70 | for (int i = 0; i < length; i++) {
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71 | avg = 0;
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72 | for (int j = 0; j < parentsCount; j++)
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73 | avg += parents[j][i];
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74 | avg /= parentsCount;
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75 | int min = bounds[i % bounds.Rows, 0], max = bounds[i % bounds.Rows, 1], step = 1;
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76 | if (bounds.Columns > 2) step = bounds[i % bounds.Rows, 2];
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77 | result[i] = (int)Math.Round((avg - min) / step) * step + min;
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78 | }
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79 | } catch (IndexOutOfRangeException) {
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80 | throw new ArgumentException("AverageCrossover: The parents' vectors are of different length.", "parents");
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81 | }
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82 |
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83 | return result;
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84 | }
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85 |
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86 | /// <summary>
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87 | /// Performs a single point crossover at a randomly chosen position of two
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88 | /// given parent integer vectors.
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89 | /// </summary>
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90 | /// <exception cref="ArgumentException">Thrown if there are not exactly two parents.</exception>
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91 | /// <param name="random">A random number generator.</param>
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92 | /// <param name="parents">An array containing the two integer vectors that should be crossed.</param>
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93 | /// <returns>The newly created integer vector, resulting from the single point crossover.</returns>
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94 | protected override IntegerVector Cross(IRandom random, ItemArray<IntegerVector> parents) {
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95 | return Apply(random, parents, BoundsParameter.ActualValue);
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96 | }
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97 | }
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98 | }
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