1  #region License Information


2  /* HeuristicLab


3  * Copyright (C) 20022012 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.Core;


25  using HeuristicLab.Encodings.PermutationEncoding;


26  using HeuristicLab.Optimization.Operators;


27 


28  namespace HeuristicLab.Problems.TravelingSalesman {


29  /// <summary>


30  /// An operator that performs similarity calculation between two traveling salesman solutions.


31  /// </summary>


32  /// <remarks>


33  /// The operator calculates the similarity based on the number of edges the two solutions have in common.


34  /// </remarks>


35  [Item("TSPSimilarityCalculator", "An operator that performs similarity calculation between two traveling salesman solutions. The operator calculates the similarity based on the number of edges the two solutions have in common.")]


36  public sealed class TSPSimilarityCalculator : SingleObjectiveSolutionSimilarityCalculator {


37  private TSPSimilarityCalculator(bool deserializing) : base(deserializing) { }


38  private TSPSimilarityCalculator(TSPSimilarityCalculator original, Cloner cloner) : base(original, cloner) { }


39  public TSPSimilarityCalculator() : base() { }


40 


41  public override IDeepCloneable Clone(Cloner cloner) {


42  return new TSPSimilarityCalculator(this, cloner);


43  }


44 


45  public static double CalculateSimilarity(Permutation left, Permutation right) {


46  if (left == null  right == null)


47  throw new ArgumentException("Cannot calculate similarity because one of the provided solutions or both are null.");


48  if (left.PermutationType != right.PermutationType)


49  throw new ArgumentException("Cannot calculate similarity because the provided solutions have different types.");


50  if (left.Length != right.Length)


51  throw new ArgumentException("Cannot calculate similarity because the provided solutions have different lengths.");


52  if (object.ReferenceEquals(left, right)) return 1.0;


53 


54  switch (left.PermutationType) {


55  case PermutationTypes.Absolute:


56  return CalculateAbsolute(left, right);


57  case PermutationTypes.RelativeDirected:


58  return CalculateRelativeDirected(left, right);


59  case PermutationTypes.RelativeUndirected:


60  return CalculateRelativeUndirected(left, right);


61  default:


62  throw new InvalidOperationException("unknown permutation type");


63  }


64  }


65 


66  private static double CalculateAbsolute(Permutation left, Permutation right) {


67  double similarity = 0.0;


68  for (int i = 0; i < left.Length; i++)


69  if (left[i] == right[i]) similarity++;


70 


71  return similarity / left.Length;


72  }


73 


74  private static double CalculateRelativeDirected(Permutation left, Permutation right) {


75  int[] edges = new int[right.Length];


76  for (int i = 0; i < right.Length; i++)


77  edges[right[i]] = right[(i + 1) % right.Length];


78 


79  double similarity = 0.0;


80  for (int i = 0; i < left.Length; i++)


81  if (left[(i + 1) % left.Length] == edges[left[i]]) similarity++;


82 


83  return similarity / left.Length;


84  }


85 


86  private static double CalculateRelativeUndirected(Permutation left, Permutation right) {


87  int[,] edges = new int[right.Length, 2];


88  for (int i = 0; i < right.Length; i++) {


89  edges[right[i], 0] = right[(i + 1) % right.Length];


90  edges[right[i], 1] = right[(i  1 + right.Length) % right.Length];


91  }


92 


93  double similarity = 0.0;


94  for (int i = 0; i < left.Length; i++) {


95  int targetCity = left[(i + 1) % left.Length];


96  if (targetCity == edges[left[i], 0]  targetCity == edges[left[i], 1])


97  similarity++;


98  }


99 


100  return similarity / left.Length;


101  }


102 


103  public override double CalculateSolutionSimilarity(IScope leftSolution, IScope rightSolution) {


104  var sol1 = leftSolution.Variables[SolutionVariableName].Value as Permutation;


105  var sol2 = rightSolution.Variables[SolutionVariableName].Value as Permutation;


106 


107  return CalculateSimilarity(sol1, sol2);


108  }


109  }


110  }

