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 System.Collections.Generic;
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24 | using System.Linq;
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25 | using HeuristicLab.Common;
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26 | using HeuristicLab.Core;
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27 | using HeuristicLab.Parameters;
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28 | using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
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29 |
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30 | namespace HeuristicLab.Encodings.SymbolicExpressionTreeEncoding {
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31 | /// <summary>
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32 | /// A base class for operators that manipulate real-valued vectors.
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33 | /// </summary>
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34 | [Item("TracingSymbolicExpressionTreeManipulator", "A base class for operators that manipulate symbolic expression trees.")]
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35 | [StorableClass]
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36 | public abstract class TracingSymbolicExpressionTreeManipulator : TracingSymbolicExpressionTreeOperator, ISymbolicExpressionTreeManipulator {
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37 | private const string SymbolicExpressionTreeParameterName = "SymbolicExpressionTree";
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38 | [Storable]
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39 | private readonly Dictionary<Type, byte> manipulationTypes = new Dictionary<Type, byte>();
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40 |
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41 | #region Parameter Properties
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42 | public ILookupParameter<ISymbolicExpressionTree> SymbolicExpressionTreeParameter {
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43 | get { return (ILookupParameter<ISymbolicExpressionTree>)Parameters[SymbolicExpressionTreeParameterName]; }
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44 | }
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45 | #endregion
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46 |
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47 | #region Properties
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48 | public ISymbolicExpressionTree SymbolicExpressionTree {
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49 | get { return SymbolicExpressionTreeParameter.ActualValue; }
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50 | }
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51 | #endregion
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52 |
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53 | [StorableConstructor]
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54 | protected TracingSymbolicExpressionTreeManipulator(bool deserializing) : base(deserializing) { }
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55 | protected TracingSymbolicExpressionTreeManipulator(TracingSymbolicExpressionTreeManipulator original, Cloner cloner)
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56 | : base(original, cloner) {
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57 | this.manipulationTypes = new Dictionary<Type, byte>(original.manipulationTypes);
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58 | }
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59 | public TracingSymbolicExpressionTreeManipulator()
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60 | : base() {
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61 | Parameters.Add(new LookupParameter<ISymbolicExpressionTree>(SymbolicExpressionTreeParameterName, "The symbolic expression tree on which the operator should be applied."));
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62 |
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63 | manipulationTypes.Add(typeof(FullTreeShaker), ManipulationType.FullTreeShaker);
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64 | manipulationTypes.Add(typeof(OnePointShaker), ManipulationType.OnePointShaker);
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65 | manipulationTypes.Add(typeof(ChangeNodeTypeManipulation), ManipulationType.ChangeNodeTypeManipulation);
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66 | manipulationTypes.Add(typeof(ReplaceBranchManipulation), ManipulationType.ReplaceBranchManipulation);
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67 | }
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68 |
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69 | public sealed override IOperation Apply() {
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70 | ISymbolicExpressionTree tree = SymbolicExpressionTreeParameter.ActualValue;
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71 |
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72 | AddTracingVariablesToGlobalScope();
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73 |
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74 | /* The following block needs to be explained in more detail;
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75 | * If the tree was already affected by crossover (before mutation), then:
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76 | * - it will already be contained in the GlobalTraceMap
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77 | * - In order to preserve information, a clone of the tree is created
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78 | * - The clone represents the intermediate stage of the tree, before mutation is applied
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79 | * - The clone therefore represents the child after crossover so GlobalTraceMap[clone] will get tree's parents
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80 | * and GlobalFragmentMap[clone] will get the subtree from clone that represents the cloned fragment
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81 | * - After tree is mutated, we set GlobalTraceMap[tree] = clone and GlobalFragmentMap[tree] = modified node from tree
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82 | */
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83 | Fragment fragment = null;
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84 | if (GlobalTraceMap.ContainsKey(tree)) {
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85 | var clone = (IItem)tree.Clone();
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86 | GlobalCloneMap[clone] = GlobalCloneMap[tree];
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87 | GlobalCloneMap[tree] = clone;
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88 | GlobalTraceMap[clone] = GlobalTraceMap[tree]; // clone gets parents of tree
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89 | GlobalTraceMap[tree] = new ItemList<IItem> { clone }; // tree gets clone as parent
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90 | fragment = (Fragment)GlobalFragmentMap[tree];
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91 | int index = tree.IterateNodesBreadth().ToList().IndexOf(fragment.Root); // returns -1 if fragment is not present in tree (can happen if fragment is null)
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92 | GlobalFragmentMap[clone] = new Fragment(index == -1 ? null : ((ISymbolicExpressionTree)clone).IterateNodesBreadth().ElementAt(index));
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93 | } else {
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94 | GlobalTraceMap[tree] = new ItemList<IItem> { GlobalCloneMap[tree] };
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95 | }
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96 |
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97 | var concreteType = this.GetType();
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98 |
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99 | if (!manipulationTypes.ContainsKey(concreteType))
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100 | throw new Exception(this.Name + ": Unknown manipulation type (key not found in the dictionary).");
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101 |
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102 | var nodes0 = tree.IterateNodesBreadth().ToList(); // list of nodes before manipulation
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103 | Manipulate(RandomParameter.ActualValue, tree);
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104 | var nodes1 = tree.IterateNodesBreadth().ToList(); // list of nodes after manipulation
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105 | int min = Math.Min(nodes0.Count, nodes1.Count);
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106 |
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107 | switch (manipulationTypes[concreteType]) {
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108 | case ManipulationType.FullTreeShaker: {
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109 | // the FullTreeShaker changes the local parameters of all the nodes in the tree
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110 | // therefore, the whole tree is considered to be the fragment
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111 | fragment = new Fragment(tree.Root.GetSubtree(0).GetSubtree(0));
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112 | break;
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113 | }
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114 | case ManipulationType.OnePointShaker: {
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115 | var original = (ISymbolicExpressionTree)GlobalCloneMap[tree];
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116 | var nodesOriginal = original.IterateNodesBreadth().ToList();
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117 | int i = 0;
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118 | var comparer = SymbolicExpressionTreeNodeComparer;
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119 | while (i != min && comparer.Equals(nodesOriginal[i], nodes1[i])) ++i;
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120 | fragment = new Fragment(i == min ? null : nodes1[i], 1);
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121 | break;
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122 | }
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123 | case ManipulationType.ChangeNodeTypeManipulation: {
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124 | int i = 0;
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125 | while (i != min && ReferenceEquals(nodes0[i], nodes1[i])) ++i;
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126 | fragment = new Fragment(i == min ? null : nodes1[i], 1);
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127 | break;
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128 | }
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129 | case ManipulationType.ReplaceBranchManipulation: {
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130 | int i = 0;
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131 | while (i != min && ReferenceEquals(nodes0[i], nodes1[i])) ++i;
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132 | fragment = new Fragment(i == min ? null : nodes1[i]);
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133 | break;
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134 | }
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135 | default:
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136 | throw new Exception(Name + ": Unknown manipulaton type.");
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137 | }
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138 |
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139 | GlobalFragmentMap[tree] = fragment;
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140 | return base.Apply();
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141 | }
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142 |
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143 | protected abstract void Manipulate(IRandom random, ISymbolicExpressionTree symbolicExpressionTree);
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144 |
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145 | private struct ManipulationType {
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146 | public const byte FullTreeShaker = 1;
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147 | public const byte OnePointShaker = 2;
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148 | public const byte ChangeNodeTypeManipulation = 3;
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149 | public const byte ReplaceBranchManipulation = 4;
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150 | }
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151 | }
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152 | }
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