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source: trunk/sources/HeuristicLab.Problems.DataAnalysis.Regression/3.3/Symbolic/SimpleArithmeticExpressionEvaluator.cs @ 3257

Last change on this file since 3257 was 3257, checked in by gkronber, 13 years ago

Moved general set of symbols and evaluator into Encodings.SymbolicExpressionTreeEncoding. #937 (Data types and operators for symbolic expression tree encoding)

File size: 2.7 KB
Line 
1#region License Information
2/* HeuristicLab
3 * Copyright (C) 2002-2010 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 HeuristicLab.Common;
24using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
25using HeuristicLab.Core;
26using System.Collections.Generic;
27using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
28using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.GeneralSymbols;
29using HeuristicLab.Problems.DataAnalysis.Regression.Symbolic.Symbols;
30
31namespace HeuristicLab.Problems.DataAnalysis.Regression.Symbolic {
32  /// <summary>
33  /// Evaluates FunctionTrees recursively by interpretation of the function symbols in each node.
34  /// Simple unoptimized code, arithmetic expressions only.
35  /// Not thread-safe!
36  /// </summary>
37  [StorableClass]
38  [Item("SimpleArithmeticExpressionEvaluator", "Default evaluator for arithmetic symbolic expression trees.")]
39  public class SimpleArithmeticExpressionEvaluator : GeneralSymbolicExpressionTreeEvaluator {
40    private Dataset dataset;
41    private int row;
42    public IEnumerable<double> EstimatedValues(SymbolicExpressionTree tree, Dataset dataset, IEnumerable<int> rows) {
43      this.dataset = dataset;
44      foreach (var row in rows) {
45        this.row = row;
46        var estimatedValue = Evaluate(tree.Root.SubTrees[0]);
47        if (double.IsNaN(estimatedValue) || double.IsInfinity(estimatedValue)) yield return 0.0;
48        else yield return estimatedValue;
49      }
50    }
51
52    public override double Evaluate(SymbolicExpressionTreeNode node) {
53      if (node.Symbol is HeuristicLab.Problems.DataAnalysis.Regression.Symbolic.Symbols.Variable) {
54        var variableTreeNode = node as VariableTreeNode;
55        return dataset[row, 1 /*dataset.VariableIndex(variableTreeNode.VariableName)*/] * 1.0; //variableTreeNode.Weight;
56      } else if (node.Symbol is Constant) {
57        return ((ConstantTreeNode)node).Value;
58      } else {
59        return base.Evaluate(node);
60      }
61    }
62  }
63}
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