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source: tags/3.3.8/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/SymbolicDataAnalysisModel.cs

Last change on this file was 9456, checked in by swagner, 11 years ago

Updated copyright year and added some missing license headers (#1889)

File size: 6.3 KB
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1#region License Information
2/* HeuristicLab
3 * Copyright (C) 2002-2013 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
4 *
5 * This file is part of HeuristicLab.
6 *
7 * HeuristicLab is free software: you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation, either version 3 of the License, or
10 * (at your option) any later version.
11 *
12 * HeuristicLab is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
19 */
20#endregion
21
22using System;
23using System.Drawing;
24using HeuristicLab.Common;
25using HeuristicLab.Core;
26using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
27using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
28
29namespace HeuristicLab.Problems.DataAnalysis.Symbolic {
30  /// <summary>
31  /// Abstract base class for symbolic data analysis models
32  /// </summary>
33  [StorableClass]
34  public abstract class SymbolicDataAnalysisModel : NamedItem, ISymbolicDataAnalysisModel {
35    public static new Image StaticItemImage {
36      get { return HeuristicLab.Common.Resources.VSImageLibrary.Function; }
37    }
38
39    #region properties
40
41    [Storable]
42    private ISymbolicExpressionTree symbolicExpressionTree;
43    public ISymbolicExpressionTree SymbolicExpressionTree {
44      get { return symbolicExpressionTree; }
45    }
46
47    [Storable]
48    private ISymbolicDataAnalysisExpressionTreeInterpreter interpreter;
49    public ISymbolicDataAnalysisExpressionTreeInterpreter Interpreter {
50      get { return interpreter; }
51    }
52
53    #endregion
54
55    [StorableConstructor]
56    protected SymbolicDataAnalysisModel(bool deserializing) : base(deserializing) { }
57    protected SymbolicDataAnalysisModel(SymbolicDataAnalysisModel original, Cloner cloner)
58      : base(original, cloner) {
59      this.symbolicExpressionTree = cloner.Clone(original.symbolicExpressionTree);
60      this.interpreter = cloner.Clone(original.interpreter);
61    }
62    public SymbolicDataAnalysisModel(ISymbolicExpressionTree tree, ISymbolicDataAnalysisExpressionTreeInterpreter interpreter)
63      : base() {
64      this.name = ItemName;
65      this.description = ItemDescription;
66      this.symbolicExpressionTree = tree;
67      this.interpreter = interpreter;
68    }
69
70    #region Scaling
71    protected void Scale(IDataAnalysisProblemData problemData, string targetVariable) {
72      var dataset = problemData.Dataset;
73      var rows = problemData.TrainingIndices;
74      var estimatedValues = Interpreter.GetSymbolicExpressionTreeValues(SymbolicExpressionTree, dataset, rows);
75      var targetValues = dataset.GetDoubleValues(targetVariable, rows);
76
77      var linearScalingCalculator = new OnlineLinearScalingParameterCalculator();
78      var targetValuesEnumerator = targetValues.GetEnumerator();
79      var estimatedValuesEnumerator = estimatedValues.GetEnumerator();
80      while (targetValuesEnumerator.MoveNext() & estimatedValuesEnumerator.MoveNext()) {
81        double target = targetValuesEnumerator.Current;
82        double estimated = estimatedValuesEnumerator.Current;
83        if (!double.IsNaN(estimated) && !double.IsInfinity(estimated))
84          linearScalingCalculator.Add(estimated, target);
85      }
86      if (linearScalingCalculator.ErrorState == OnlineCalculatorError.None && (targetValuesEnumerator.MoveNext() || estimatedValuesEnumerator.MoveNext()))
87        throw new ArgumentException("Number of elements in target and estimated values enumeration do not match.");
88
89      double alpha = linearScalingCalculator.Alpha;
90      double beta = linearScalingCalculator.Beta;
91      if (linearScalingCalculator.ErrorState != OnlineCalculatorError.None) return;
92
93      ConstantTreeNode alphaTreeNode = null;
94      ConstantTreeNode betaTreeNode = null;
95      // check if model has been scaled previously by analyzing the structure of the tree
96      var startNode = SymbolicExpressionTree.Root.GetSubtree(0);
97      if (startNode.GetSubtree(0).Symbol is Addition) {
98        var addNode = startNode.GetSubtree(0);
99        if (addNode.SubtreeCount == 2 && addNode.GetSubtree(0).Symbol is Multiplication && addNode.GetSubtree(1).Symbol is Constant) {
100          alphaTreeNode = addNode.GetSubtree(1) as ConstantTreeNode;
101          var mulNode = addNode.GetSubtree(0);
102          if (mulNode.SubtreeCount == 2 && mulNode.GetSubtree(1).Symbol is Constant) {
103            betaTreeNode = mulNode.GetSubtree(1) as ConstantTreeNode;
104          }
105        }
106      }
107      // if tree structure matches the structure necessary for linear scaling then reuse the existing tree nodes
108      if (alphaTreeNode != null && betaTreeNode != null) {
109        betaTreeNode.Value *= beta;
110        alphaTreeNode.Value *= beta;
111        alphaTreeNode.Value += alpha;
112      } else {
113        var mainBranch = startNode.GetSubtree(0);
114        startNode.RemoveSubtree(0);
115        var scaledMainBranch = MakeSum(MakeProduct(mainBranch, beta), alpha);
116        startNode.AddSubtree(scaledMainBranch);
117      }
118    }
119
120    private static ISymbolicExpressionTreeNode MakeSum(ISymbolicExpressionTreeNode treeNode, double alpha) {
121      if (alpha.IsAlmost(0.0)) {
122        return treeNode;
123      } else {
124        var addition = new Addition();
125        var node = addition.CreateTreeNode();
126        var alphaConst = MakeConstant(alpha);
127        node.AddSubtree(treeNode);
128        node.AddSubtree(alphaConst);
129        return node;
130      }
131    }
132
133    private static ISymbolicExpressionTreeNode MakeProduct(ISymbolicExpressionTreeNode treeNode, double beta) {
134      if (beta.IsAlmost(1.0)) {
135        return treeNode;
136      } else {
137        var multipliciation = new Multiplication();
138        var node = multipliciation.CreateTreeNode();
139        var betaConst = MakeConstant(beta);
140        node.AddSubtree(treeNode);
141        node.AddSubtree(betaConst);
142        return node;
143      }
144    }
145
146    private static ISymbolicExpressionTreeNode MakeConstant(double c) {
147      var node = (ConstantTreeNode)(new Constant()).CreateTreeNode();
148      node.Value = c;
149      return node;
150    }
151    #endregion
152  }
153}
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