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.Persistence.Default.CompositeSerializers.Storable;


24  using HeuristicLab.Core;


25  using System.Collections.Generic;


26  using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;


27  using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding.GeneralSymbols;


28 


29  namespace HeuristicLab.Encodings.SymbolicExpressionTreeEncoding {


30  /// <summary>


31  /// Evaluates FunctionTrees recursively by interpretation of the function symbols in each node.


32  /// Simple unoptimized code, general symbolic expressions only.


33  /// Not threadsafe!


34  /// </summary>


35  [StorableClass]


36  [Item("GeneralSymbolicExpressionTreeEvaluator", "Default evaluator for symbolic expression trees.")]


37  public class GeneralSymbolicExpressionTreeEvaluator : Item {


38  public virtual double Evaluate(SymbolicExpressionTreeNode node) {


39  if (node.Symbol is Addition) {


40  return Evaluate(node.SubTrees[0]) + Evaluate(node.SubTrees[1]);


41  } else if (node.Symbol is Subtraction) {


42  return Evaluate(node.SubTrees[0])  Evaluate(node.SubTrees[1]);


43  } else if (node.Symbol is Multiplication) {


44  return Evaluate(node.SubTrees[0]) * Evaluate(node.SubTrees[1]);


45  } else if (node.Symbol is Division) {


46  return Evaluate(node.SubTrees[0]) / Evaluate(node.SubTrees[1]);


47  } else {


48  throw new NotSupportedException("Tree contains unknown symbol: " + node.Symbol.Name);


49  }


50  }


51  }


52  }

