1 | #region License Information |
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2 | /* HeuristicLab |
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3 | * Copyright (C) 2002-2019 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.Persistence.Default.CompositeSerializers.Storable; |
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26 | |
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27 | namespace HeuristicLab.Encodings.PermutationEncoding { |
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28 | /// <summary> |
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29 | /// An operator which performs the order crossover on two permutations. |
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30 | /// </summary> |
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31 | /// <remarks> |
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32 | /// It is implemented as described in Eiben, A.E. and Smith, J.E. 2003. Introduction to Evolutionary Computation. Natural Computing Series, Springer-Verlag Berlin Heidelberg.<br /> |
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33 | /// Crosses two permutations by copying a randomly chosen interval from the first permutation, preserving |
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34 | /// the positions. Then, starting from the end of the copied interval, copies the missing values from the second permutation |
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35 | /// in the order they occur. |
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36 | /// </remarks> |
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37 | [Item("OrderCrossover", "An operator which performs an order crossover of two permutations. It is implemented as described in Eiben, A.E. and Smith, J.E. 2003. Introduction to Evolutionary Computation. Natural Computing Series, Springer-Verlag Berlin Heidelberg.")] |
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38 | [StorableClass] |
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39 | public class OrderCrossover : PermutationCrossover { |
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40 | [StorableConstructor] |
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41 | protected OrderCrossover(bool deserializing) : base(deserializing) { } |
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42 | protected OrderCrossover(OrderCrossover original, Cloner cloner) : base(original, cloner) { } |
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43 | public OrderCrossover() : base() { } |
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44 | |
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45 | public override IDeepCloneable Clone(Cloner cloner) { |
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46 | return new OrderCrossover(this, cloner); |
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47 | } |
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48 | |
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49 | /// <summary> |
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50 | /// Performs the order crossover of two permutations. |
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51 | /// </summary> |
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52 | /// <exception cref="ArgumentException">Thrown when <paramref name="parent1"/> and <paramref name="parent2"/> are not of equal length.</exception> |
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53 | /// <exception cref="InvalidOperationException">Thrown if the numbers in the permutation elements are not in the range [0,N) with N = length of the permutation.</exception> |
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54 | /// <remarks> |
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55 | /// Crosses two permutations by copying a randomly chosen interval from the first permutation, preserving |
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56 | /// the positions. Then, starting from the end of the copied interval, copies the missing values from the second permutation |
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57 | /// in the order they occur. |
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58 | /// </remarks> |
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59 | /// <param name="random">A random number generator.</param> |
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60 | /// <param name="parent1">The first parent permutation to cross.</param> |
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61 | /// <param name="parent2">The second parent permutation to cross.</param> |
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62 | /// <returns>The new permutation resulting from the crossover.</returns> |
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63 | public static Permutation Apply(IRandom random, Permutation parent1, Permutation parent2) { |
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64 | if (parent1.Length != parent2.Length) throw new ArgumentException("OrderCrossover: The parent permutations are of unequal length."); |
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65 | int length = parent1.Length; |
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66 | int[] result = new int[length]; |
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67 | bool[] copied = new bool[length]; |
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68 | |
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69 | int breakPoint1 = random.Next(length - 1); |
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70 | int breakPoint2 = random.Next(breakPoint1 + 1, length); |
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71 | |
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72 | try { |
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73 | for (int j = breakPoint1; j <= breakPoint2; j++) { // copy part of first permutation |
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74 | result[j] = parent1[j]; |
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75 | copied[parent1[j]] = true; |
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76 | } |
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77 | |
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78 | int index = ((breakPoint2 + 1 >= length) ? (0) : (breakPoint2 + 1)); |
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79 | int i = index; // for moving in parent2 |
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80 | while (index != breakPoint1) { |
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81 | if (!copied[parent2[i]]) { |
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82 | result[index] = parent2[i]; |
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83 | index++; |
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84 | if (index >= length) index = 0; |
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85 | } |
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86 | i++; |
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87 | if (i >= length) i = 0; |
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88 | } |
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89 | } |
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90 | catch (IndexOutOfRangeException) { |
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91 | throw new InvalidOperationException("OrderCrossover: The permutation must consist of numbers in the interval [0;N) with N = length of the permutation."); |
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92 | } |
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93 | return new Permutation(parent1.PermutationType, result); |
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94 | } |
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95 | |
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96 | /// <summary> |
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97 | /// Checks number of parents and calls <see cref="Apply(IRandom, Permutation, Permutation)"/>. |
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98 | /// </summary> |
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99 | /// <exception cref="InvalidOperationException">Thrown if there are not exactly two parents.</exception> |
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100 | /// <param name="random">A random number generator.</param> |
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101 | /// <param name="parents">An array containing the two permutations that should be crossed.</param> |
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102 | /// <returns>The new permutation resulting from the crossover.</returns> |
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103 | protected override Permutation Cross(IRandom random, ItemArray<Permutation> parents) { |
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104 | if (parents.Length != 2) throw new InvalidOperationException("OrderCrossover: Number of parents is not equal to 2."); |
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105 | return Apply(random, parents[0], parents[1]); |
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106 | } |
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107 | } |
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108 | } |
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