1  #region License Information


2  /* HeuristicLab


3  * Copyright (C) 20022015 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 System.Threading;


24  using HeuristicLab.Common;


25  using HeuristicLab.Core;


26  using HeuristicLab.Data;


27  using HeuristicLab.Encodings.PermutationEncoding;


28  using HeuristicLab.Operators;


29  using HeuristicLab.Optimization;


30  using HeuristicLab.Parameters;


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


32 


33  namespace HeuristicLab.Problems.PTSP {


34  /// <summary>


35  /// An operator that improves probabilistic traveling salesman solutions.


36  /// </summary>


37  /// <remarks>


38  /// The operator tries to improve the probabilistic traveling salesman solution by swapping two randomly chosen edges for a certain number of times.


39  /// </remarks>


40  [Item("PTSPExhaustiveInversionLocalImprovement", "An operator that improves probabilistic traveling salesman solutions. The operator tries to improve the probabilistic traveling salesman solution by swapping two randomly chosen edges for a certain number of times.")]


41  [StorableClass]


42  public sealed class PTSPExhaustiveInversionLocalImprovement : SingleSuccessorOperator, IEstimatedPTSPOperator, ILocalImprovementOperator {


43 


44  public ILookupParameter<IntValue> LocalIterationsParameter {


45  get { return (ILookupParameter<IntValue>)Parameters["LocalIterations"]; }


46  }


47 


48  public IValueLookupParameter<IntValue> MaximumIterationsParameter {


49  get { return (IValueLookupParameter<IntValue>)Parameters["MaximumIterations"]; }


50  }


51 


52  public ILookupParameter<IntValue> EvaluatedSolutionsParameter {


53  get { return (ILookupParameter<IntValue>)Parameters["EvaluatedSolutions"]; }


54  }


55 


56  public ILookupParameter<ResultCollection> ResultsParameter {


57  get { return (ILookupParameter<ResultCollection>)Parameters["Results"]; }


58  }


59 


60  public ILookupParameter<Permutation> PermutationParameter {


61  get { return (ILookupParameter<Permutation>)Parameters["Permutation"]; }


62  }


63 


64  public ILookupParameter<DoubleValue> QualityParameter {


65  get { return (ILookupParameter<DoubleValue>)Parameters["Quality"]; }


66  }


67 


68  public ILookupParameter<BoolValue> MaximizationParameter {


69  get { return (ILookupParameter<BoolValue>)Parameters["Maximization"]; }


70  }


71 


72  public ILookupParameter<DistanceMatrix> DistanceMatrixParameter {


73  get { return (ILookupParameter<DistanceMatrix>)Parameters["DistanceMatrix"]; }


74  }


75 


76  public ILookupParameter<ItemList<BoolArray>> RealizationsParameter {


77  get { return (ILookupParameter<ItemList<BoolArray>>)Parameters["Realizations"]; }


78  }


79 


80  [StorableConstructor]


81  private PTSPExhaustiveInversionLocalImprovement(bool deserializing) : base(deserializing) { }


82  private PTSPExhaustiveInversionLocalImprovement(PTSPExhaustiveInversionLocalImprovement original, Cloner cloner) : base(original, cloner) { }


83  public PTSPExhaustiveInversionLocalImprovement()


84  : base() {


85  Parameters.Add(new LookupParameter<Permutation>("Permutation", "The solution as permutation."));


86  Parameters.Add(new LookupParameter<IntValue>("LocalIterations", "The number of iterations that have already been performed."));


87  Parameters.Add(new ValueLookupParameter<IntValue>("MaximumIterations", "The maximum amount of iterations that should be performed (note that this operator will abort earlier when a local optimum is reached).", new IntValue(10000)));


88  Parameters.Add(new LookupParameter<IntValue>("EvaluatedSolutions", "The amount of evaluated solutions (here a move is counted only as 4/n evaluated solutions with n being the length of the permutation)."));


89  Parameters.Add(new LookupParameter<ResultCollection>("Results", "The collection where to store results."));


90  Parameters.Add(new LookupParameter<DoubleValue>("Quality", "The quality value of the assignment."));


91  Parameters.Add(new LookupParameter<BoolValue>("Maximization", "True if the problem should be maximized or minimized."));


92  Parameters.Add(new LookupParameter<DistanceMatrix>("DistanceMatrix", "The matrix which contains the distances between the cities."));


93  Parameters.Add(new LookupParameter<ItemList<BoolArray>>("Realizations", "The list of samples drawn from all possible stochastic instances."));


94  }


95 


96  public override IDeepCloneable Clone(Cloner cloner) {


97  return new PTSPExhaustiveInversionLocalImprovement(this, cloner);


98  }


99 


100  public static void Improve(Permutation assignment, DoubleMatrix distances, DoubleValue quality, IntValue localIterations, IntValue evaluatedSolutions, bool maximization, int maxIterations, CancellationToken cancellation, ItemList<BoolArray> realizations) {


101  var distanceM = (DistanceMatrix)distances;


102  for (var i = localIterations.Value; i < maxIterations; i++) {


103  InversionMove bestMove = null;


104  double bestQuality = 0; // we have to make an improvement, so 0 is the baseline


105  double evaluations = 0.0;


106  foreach (var move in ExhaustiveInversionMoveGenerator.Generate(assignment)) {


107  double moveQuality = PTSPEstimatedInversionMoveEvaluator.EvaluateByDistanceMatrix(assignment, move, distanceM, realizations);


108  evaluations += 2 * (move.Index2  move.Index1 + 1) / (double)assignment.Length;


109  if (maximization && moveQuality > bestQuality


110   !maximization && moveQuality < bestQuality) {


111  bestQuality = moveQuality;


112  bestMove = move;


113  }


114  }


115  evaluatedSolutions.Value += (int)Math.Ceiling(evaluations);


116  if (bestMove == null) break;


117  InversionManipulator.Apply(assignment, bestMove.Index1, bestMove.Index2);


118  quality.Value += bestQuality;


119  localIterations.Value++;


120  cancellation.ThrowIfCancellationRequested();


121  }


122  }


123 


124  public override IOperation Apply() {


125  var maxIterations = MaximumIterationsParameter.ActualValue.Value;


126  var assignment = PermutationParameter.ActualValue;


127  var maximization = MaximizationParameter.ActualValue.Value;


128  var distances = DistanceMatrixParameter.ActualValue;


129  var quality = QualityParameter.ActualValue;


130  var localIterations = LocalIterationsParameter.ActualValue;


131  var evaluations = EvaluatedSolutionsParameter.ActualValue;


132  var realizations = RealizationsParameter.ActualValue;


133  if (localIterations == null) {


134  localIterations = new IntValue(0);


135  LocalIterationsParameter.ActualValue = localIterations;


136  }


137 


138  Improve(assignment, distances, quality, localIterations, evaluations, maximization, maxIterations, CancellationToken, realizations);


139 


140  localIterations.Value = 0;


141  return base.Apply();


142  }


143  }


144  }

