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;
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23 | using System.Collections.Generic;
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24 | using System.Linq;
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25 | using HeuristicLab.Core;
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26 | using HeuristicLab.Data;
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27 | using HeuristicLab.Operators;
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28 | using HeuristicLab.Random;
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29 | using HeuristicLab.Functions;
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30 | using System.Diagnostics;
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31 |
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32 | namespace HeuristicLab.StructureIdentification {
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33 | public class SubstituteSubTreeManipulation : OperatorBase {
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34 |
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35 | public override string Description {
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36 | get { return "Selects a random node of the tree and replaces it with randomly initialized subtree."; }
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37 | }
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38 |
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39 | public SubstituteSubTreeManipulation()
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40 | : base() {
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41 | AddVariableInfo(new VariableInfo("Random", "Uniform random number generator", typeof(MersenneTwister), VariableKind.In));
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42 | AddVariableInfo(new VariableInfo("OperatorLibrary", "The operator library containing all available operators", typeof(GPOperatorLibrary), VariableKind.In));
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43 | AddVariableInfo(new VariableInfo("MaxTreeHeight", "The maximal allowed height of the tree", typeof(IntData), VariableKind.In));
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44 | AddVariableInfo(new VariableInfo("MaxTreeSize", "The maximal allowed size (number of nodes) of the tree", typeof(IntData), VariableKind.In));
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45 | AddVariableInfo(new VariableInfo("FunctionTree", "The tree to manipulate", typeof(IFunctionTree), VariableKind.In | VariableKind.Out));
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46 | AddVariableInfo(new VariableInfo("TreeSize", "The size (number of nodes) of the tree", typeof(IntData), VariableKind.In | VariableKind.Out));
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47 | AddVariableInfo(new VariableInfo("TreeHeight", "The height of the tree", typeof(IntData), VariableKind.In | VariableKind.Out));
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48 | }
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49 |
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50 | public override IOperation Apply(IScope scope) {
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51 | IFunctionTree root = GetVariableValue<IFunctionTree>("FunctionTree", scope, true);
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52 | MersenneTwister random = GetVariableValue<MersenneTwister>("Random", scope, true);
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53 | GPOperatorLibrary library = GetVariableValue<GPOperatorLibrary>("OperatorLibrary", scope, true);
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54 | int maxTreeHeight = GetVariableValue<IntData>("MaxTreeHeight", scope, true).Data;
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55 | int maxTreeSize = GetVariableValue<IntData>("MaxTreeSize", scope, true).Data;
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56 | int treeSize = GetVariableValue<IntData>("TreeSize", scope, true).Data;
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57 | int treeHeight = GetVariableValue<IntData>("TreeHeight", scope, true).Data;
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58 | TreeGardener gardener = new TreeGardener(random, library);
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59 | IFunctionTree parent = gardener.GetRandomParentNode(root);
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60 | if(parent == null) {
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61 | // parent == null means we should subsitute the whole tree
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62 | // => create a new random tree
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63 | IFunctionTree newTree = gardener.CreateRandomTree(gardener.AllFunctions, maxTreeSize, maxTreeHeight);
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64 | Debug.Assert(gardener.IsValidTree(newTree));
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65 |
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66 | // update the variables in the scope with the new values
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67 | GetVariableValue<IntData>("TreeSize", scope, true).Data = gardener.GetTreeSize(newTree);
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68 | GetVariableValue<IntData>("TreeHeight", scope, true).Data = gardener.GetTreeHeight(newTree);
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69 | scope.GetVariable(scope.TranslateName("FunctionTree")).Value = newTree;
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70 |
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71 | // return a CompositeOperation that randomly initializes the new tree
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72 | return gardener.CreateInitializationOperation(gardener.GetAllSubTrees(newTree), scope);
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73 | } else {
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74 | // determine a random child of the parent to be replaced
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75 | int childIndex = random.Next(parent.SubTrees.Count);
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76 | // get the list of allowed functions for the new sub-tree
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77 | ICollection<IFunction> allowedFunctions = gardener.GetAllowedSubFunctions(parent.Function, childIndex);
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78 | if(allowedFunctions.Count == 0) {
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79 | // don't change anything
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80 | // this shouldn't happen
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81 | throw new InvalidProgramException();
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82 | }
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83 |
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84 | // calculate the maximum size and height of the new sub-tree based on the location where
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85 | // it will be inserted
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86 | int parentLevel = gardener.GetBranchLevel(root, parent);
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87 | int maxSubTreeHeight = maxTreeHeight - parentLevel;
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88 | int maxSubTreeSize = maxTreeSize - (treeSize - gardener.GetTreeSize(parent.SubTrees[childIndex]));
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89 |
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90 | // create a random function tree
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91 | IFunctionTree newTree = gardener.CreateRandomTree(allowedFunctions, maxSubTreeSize, maxSubTreeHeight);
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92 | parent.RemoveSubTree(childIndex);
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93 | parent.InsertSubTree(childIndex, newTree);
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94 |
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95 | Debug.Assert(gardener.IsValidTree(root));
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96 | // update the values of treeSize and treeHeight
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97 | GetVariableValue<IntData>("TreeSize", scope, true).Data = gardener.GetTreeSize(root);
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98 | GetVariableValue<IntData>("TreeHeight", scope, true).Data = gardener.GetTreeHeight(root);
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99 | // the root hasn't changed so we don't need to update
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100 | // return a CompositeOperation that randomly initializes all nodes of the new subtree
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101 | return gardener.CreateInitializationOperation(gardener.GetAllSubTrees(newTree), scope);
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102 | }
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103 | }
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104 | }
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105 | }
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