1 | #region License Information
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2 | /* HeuristicLab
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3 | * Copyright (C) 2002-2010 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.Persistence.Default.CompositeSerializers.Storable;
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25 | using HeuristicLab.Core;
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26 | using System.Collections.Generic;
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27 | using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
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28 | using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.GeneralSymbols;
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29 | using HeuristicLab.Problems.DataAnalysis.Regression.Symbolic.Symbols;
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30 |
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31 | namespace HeuristicLab.Problems.DataAnalysis.Regression.Symbolic {
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32 | /// <summary>
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33 | /// Evaluates FunctionTrees recursively by interpretation of the function symbols in each node.
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34 | /// Simple unoptimized code, arithmetic expressions only.
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35 | /// Not thread-safe!
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36 | /// </summary>
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37 | [StorableClass]
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38 | [Item("SimpleArithmeticExpressionEvaluator", "Default evaluator for arithmetic symbolic expression trees.")]
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39 | public class SimpleArithmeticExpressionEvaluator : GeneralSymbolicExpressionTreeEvaluator {
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40 | private Dataset dataset;
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41 | private int row;
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42 | public IEnumerable<double> EstimatedValues(SymbolicExpressionTree tree, Dataset dataset, IEnumerable<int> rows) {
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43 | this.dataset = dataset;
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44 | foreach (var row in rows) {
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45 | this.row = row;
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46 | var estimatedValue = Evaluate(tree.Root.SubTrees[0]);
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47 | if (double.IsNaN(estimatedValue) || double.IsInfinity(estimatedValue)) yield return 0.0;
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48 | else yield return estimatedValue;
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49 | }
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50 | }
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51 |
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52 | public override double Evaluate(SymbolicExpressionTreeNode node) {
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53 | if (node.Symbol is HeuristicLab.Problems.DataAnalysis.Regression.Symbolic.Symbols.Variable) {
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54 | var variableTreeNode = node as VariableTreeNode;
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55 | return dataset[row, dataset.VariableIndex(variableTreeNode.VariableName)] * variableTreeNode.Weight;
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56 | } else if (node.Symbol is Constant) {
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57 | return ((ConstantTreeNode)node).Value;
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58 | } else {
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59 | return base.Evaluate(node);
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60 | }
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61 | }
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62 | }
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63 | }
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