1  #region License Information


2  /* HeuristicLab


3  * Copyright (C) 20022010 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 


22  using System;


23  using HeuristicLab.Common;


24  using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;


25  using HeuristicLab.Core;


26  using System.Collections.Generic;


27  using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;


28  using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.GeneralSymbols;


29  using HeuristicLab.Problems.DataAnalysis.Regression.Symbolic.Symbols;


30 


31  namespace 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 threadsafe!


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  }

