1 | #region License Information
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2 | /* HeuristicLab
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3 | * Copyright (C) 2002-2008 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.Collections.Generic;
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23 | using System.Linq;
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24 | using HeuristicLab.Core;
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25 | using HeuristicLab.Data;
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26 | using HeuristicLab.Operators;
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27 | using HeuristicLab.Random;
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28 | using System;
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29 | using HeuristicLab.Functions;
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30 |
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31 | namespace HeuristicLab.StructureIdentification {
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32 | public class CutOutNodeManipulation : OperatorBase {
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33 | public override string Description {
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34 | get {
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35 | return @"Takes a tree, selects a random node of the tree and then tries to replace a random sub-tree
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36 | of that node with one of the childs of the selected child.
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37 |
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38 | O O
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39 | / \ / \
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40 | O X O 2
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41 | / \ 2 is selected => / \
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42 | 1 2 4 5
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43 | / / \
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44 | 3 4 5
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45 | ";
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46 | }
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47 | }
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48 |
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49 | public CutOutNodeManipulation()
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50 | : base() {
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51 | AddVariableInfo(new VariableInfo("Random", "Uniform random number generator", typeof(MersenneTwister), VariableKind.In));
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52 | AddVariableInfo(new VariableInfo("OperatorLibrary", "The operator library containing all available operators", typeof(GPOperatorLibrary), VariableKind.In));
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53 | AddVariableInfo(new VariableInfo("MaxTreeHeight", "The maximal allowed height of the tree", typeof(IntData), VariableKind.In));
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54 | AddVariableInfo(new VariableInfo("MaxTreeSize", "The maximal allowed size (number of nodes) of the tree", typeof(IntData), VariableKind.In));
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55 | AddVariableInfo(new VariableInfo("BalancedTreesRate", "Determines how many trees should be balanced", typeof(DoubleData), VariableKind.In));
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56 | AddVariableInfo(new VariableInfo("FunctionTree", "The tree to mutate", typeof(IFunctionTree), VariableKind.In | VariableKind.Out));
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57 | AddVariableInfo(new VariableInfo("TreeSize", "The size (number of nodes) of the tree", typeof(IntData), VariableKind.In | VariableKind.Out));
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58 | AddVariableInfo(new VariableInfo("TreeHeight", "The height of the tree", typeof(IntData), VariableKind.In | VariableKind.Out));
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59 | }
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60 |
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61 |
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62 | public override IOperation Apply(IScope scope) {
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63 | IFunctionTree root = GetVariableValue<IFunctionTree>("FunctionTree", scope, true);
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64 | MersenneTwister random = GetVariableValue<MersenneTwister>("Random", scope, true);
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65 | GPOperatorLibrary library = GetVariableValue<GPOperatorLibrary>("OperatorLibrary", scope, true);
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66 | int maxTreeHeight = GetVariableValue<IntData>("MaxTreeHeight", scope, true).Data;
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67 | int maxTreeSize = GetVariableValue<IntData>("MaxTreeSize", scope, true).Data;
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68 | double balancedTreesRate = GetVariableValue<DoubleData>("BalancedTreesRate", scope, true).Data;
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69 |
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70 | TreeGardener gardener = new TreeGardener(random, library);
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71 | IFunctionTree parent = gardener.GetRandomParentNode(root);
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72 | // parent == null means we should cut out the root node
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73 | // => return a random sub-tree of the root
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74 | if (parent == null) {
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75 | // when there are sub-trees then replace the old tree with a random sub-tree
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76 | if (root.SubTrees.Count > 0) {
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77 | root = root.SubTrees[random.Next(root.SubTrees.Count)];
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78 |
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79 | GetVariableValue<IntData>("TreeSize", scope, true).Data = gardener.GetTreeSize(root);
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80 | GetVariableValue<IntData>("TreeHeight", scope, true).Data = gardener.GetTreeHeight(root);
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81 |
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82 | // this is not really necessary (we can leave it in until the tree is stable)
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83 | if (!gardener.IsValidTree(root)) {
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84 | throw new InvalidProgramException();
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85 | }
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86 |
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87 | // update the variable
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88 | scope.GetVariable(scope.TranslateName("FunctionTree")).Value = root;
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89 | if (!gardener.IsValidTree(root)) {
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90 | throw new InvalidProgramException();
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91 | }
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92 | // the tree is already initialized so we don't have to schedule initialization operations
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93 | return null;
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94 | } else {
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95 | // create a new random tree
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96 | IFunctionTree newTree;
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97 | if(random.NextDouble() <= balancedTreesRate) {
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98 | newTree = gardener.CreateRandomTree(gardener.AllFunctions, maxTreeSize, maxTreeHeight, true);
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99 | } else {
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100 | newTree = gardener.CreateRandomTree(gardener.AllFunctions, maxTreeSize, maxTreeHeight, false);
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101 | }
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102 |
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103 | GetVariableValue<IntData>("TreeSize", scope, true).Data = gardener.GetTreeSize(newTree);
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104 | GetVariableValue<IntData>("TreeHeight", scope, true).Data = gardener.GetTreeHeight(newTree);
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105 |
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106 | // update the variable
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107 | scope.GetVariable(scope.TranslateName("FunctionTree")).Value = newTree;
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108 |
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109 | if (!gardener.IsValidTree(newTree)) {
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110 | throw new InvalidProgramException();
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111 | }
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112 |
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113 | // schedule an operation to initialize the whole tree
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114 | return gardener.CreateInitializationOperation(gardener.GetAllSubTrees(newTree), scope);
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115 | }
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116 | }
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117 |
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118 | int childIndex = random.Next(parent.SubTrees.Count);
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119 | IFunctionTree child = parent.SubTrees[childIndex];
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120 |
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121 | // match the sub-trees of the child with the allowed sub-trees of the parent
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122 | IFunction[] possibleChilds = gardener.GetAllowedSubFunctions(parent.Function, childIndex).SelectMany(allowedFun => child.SubTrees
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123 | .Where(subTree => allowedFun == subTree.Function)).Select(t=>t.Function).ToArray(); // Actually we should probably use OperatorEqualityComparer here (gkronber 21.04.08)
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124 |
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125 | if (possibleChilds.Length > 0) {
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126 | // replace child with a random child of the child
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127 | // make a clone to simplify removing obsolete branches from the function-tree
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128 | IFunction selectedChild = possibleChilds[random.Next(possibleChilds.Length)];
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129 | parent.RemoveSubTree(childIndex);
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130 | parent.InsertSubTree(childIndex, new FunctionTree(selectedChild));
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131 |
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132 | if (!gardener.IsValidTree(root)) {
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133 | throw new InvalidProgramException();
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134 | }
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135 |
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136 | // update the size and height of our tree
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137 | GetVariableValue<IntData>("TreeSize", scope, true).Data = gardener.GetTreeSize(root);
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138 | GetVariableValue<IntData>("TreeHeight", scope, true).Data = gardener.GetTreeHeight(root);
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139 | // don't need to schedule initialization operations
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140 | return null;
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141 | } else {
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142 | // determine the level of the parent
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143 | int parentLevel = gardener.GetBranchLevel(root, parent);
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144 |
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145 | // first remove the old child (first step essential!)
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146 | parent.RemoveSubTree(childIndex);
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147 | // then determine the number of nodes left over after the child has been removed!
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148 | int remainingNodes = gardener.GetTreeSize(root);
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149 |
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150 | IList<IFunction> allowedFunctions = gardener.GetAllowedSubFunctions(parent.Function, childIndex);
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151 | IFunctionTree newFunctionTree = gardener.CreateRandomTree(allowedFunctions, maxTreeSize - remainingNodes, maxTreeHeight - parentLevel, true);
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152 |
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153 | parent.InsertSubTree(childIndex, newFunctionTree);
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154 |
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155 | GetVariableValue<IntData>("TreeSize", scope, true).Data = gardener.GetTreeSize(root);
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156 | GetVariableValue<IntData>("TreeHeight", scope, true).Data = gardener.GetTreeHeight(root);
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157 |
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158 | if (!gardener.IsValidTree(root)) {
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159 | throw new InvalidProgramException();
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160 | }
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161 |
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162 | // schedule an initialization operation for the new function-tree
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163 | return gardener.CreateInitializationOperation(gardener.GetAllSubTrees(newFunctionTree), scope);
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164 | }
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165 | }
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166 | }
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167 | }
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