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 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.QuadraticAssignment {


34  [Item("QAPExhaustiveSwap2LocalImprovement", "Takes a solution and finds the local optimum with respect to the swap2 neighborhood by decending along the steepest gradient.")]


35  [StorableClass]


36  public class QAPExhaustiveSwap2LocalImprovement : SingleSuccessorOperator, ILocalImprovementOperator {


37 


38  public Type ProblemType {


39  get { return typeof(QuadraticAssignmentProblem); }


40  }


41 


42  [Storable]


43  private QuadraticAssignmentProblem problem;


44  public IProblem Problem {


45  get { return problem; }


46  set { problem = (QuadraticAssignmentProblem)value; }


47  }


48 


49  public ILookupParameter<IntValue> LocalIterationsParameter {


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


51  }


52 


53  public IValueLookupParameter<IntValue> MaximumIterationsParameter {


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


55  }


56 


57  public ILookupParameter<IntValue> EvaluatedSolutionsParameter {


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


59  }


60 


61  public ILookupParameter<ResultCollection> ResultsParameter {


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


63  }


64 


65  public ILookupParameter<Permutation> AssignmentParameter {


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


67  }


68 


69  public ILookupParameter<DoubleValue> QualityParameter {


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


71  }


72 


73  public ILookupParameter<BoolValue> MaximizationParameter {


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


75  }


76 


77  public ILookupParameter<DoubleMatrix> WeightsParameter {


78  get { return (ILookupParameter<DoubleMatrix>)Parameters["Weights"]; }


79  }


80 


81  public ILookupParameter<DoubleMatrix> DistancesParameter {


82  get { return (ILookupParameter<DoubleMatrix>)Parameters["Distances"]; }


83  }


84 


85  [StorableConstructor]


86  protected QAPExhaustiveSwap2LocalImprovement(bool deserializing) : base(deserializing) { }


87  protected QAPExhaustiveSwap2LocalImprovement(QAPExhaustiveSwap2LocalImprovement original, Cloner cloner)


88  : base(original, cloner) {


89  this.problem = cloner.Clone(original.problem);


90  }


91  public QAPExhaustiveSwap2LocalImprovement()


92  : base() {


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


94  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)));


95  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)."));


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


97  Parameters.Add(new LookupParameter<Permutation>("Assignment", "The permutation that is to be locally optimized."));


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


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


100  Parameters.Add(new LookupParameter<DoubleMatrix>("Weights", "The weights matrix."));


101  Parameters.Add(new LookupParameter<DoubleMatrix>("Distances", "The distances matrix."));


102  }


103 


104  public override IDeepCloneable Clone(Cloner cloner) {


105  return new QAPExhaustiveSwap2LocalImprovement(this, cloner);


106  }


107 


108  // BackwardsCompatibility3.3


109  #region Backwards compatible code, remove with 3.4


110  [StorableHook(HookType.AfterDeserialization)]


111  private void AfterDeserialization() {


112  if (!Parameters.ContainsKey("LocalIterations"))


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


114  }


115  #endregion


116 


117  public static void Improve(Permutation assignment, DoubleMatrix weights, DoubleMatrix distances, DoubleValue quality, IntValue localIterations, IntValue evaluatedSolutions, bool maximization, int maxIterations, CancellationToken cancellation) {


118  double evalSolPerMove = 4.0 / assignment.Length;


119 


120  for (int i = localIterations.Value; i < maxIterations; i++) {


121  Swap2Move bestMove = null;


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


123  double evaluations = 0.0;


124  foreach (Swap2Move move in ExhaustiveSwap2MoveGenerator.Generate(assignment)) {


125  double moveQuality = QAPSwap2MoveEvaluator.Apply(assignment, move, weights, distances);


126  evaluations += evalSolPerMove;


127  if (maximization && moveQuality > bestQuality


128   !maximization && moveQuality < bestQuality) {


129  bestQuality = moveQuality;


130  bestMove = move;


131  }


132  }


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


134  if (bestMove == null) break;


135  Swap2Manipulator.Apply(assignment, bestMove.Index1, bestMove.Index2);


136  quality.Value += bestQuality;


137  localIterations.Value++;


138  cancellation.ThrowIfCancellationRequested();


139  }


140  }


141 


142  public override IOperation Apply() {


143  var maxIterations = MaximumIterationsParameter.ActualValue.Value;


144  var assignment = AssignmentParameter.ActualValue;


145  var maximization = MaximizationParameter.ActualValue.Value;


146  var weights = WeightsParameter.ActualValue;


147  var distances = DistancesParameter.ActualValue;


148  var quality = QualityParameter.ActualValue;


149  var localIterations = LocalIterationsParameter.ActualValue;


150  var evaluations = EvaluatedSolutionsParameter.ActualValue;


151  if (localIterations == null) {


152  localIterations = new IntValue(0);


153  LocalIterationsParameter.ActualValue = localIterations;


154  }


155 


156  Improve(assignment, weights, distances, quality, localIterations, evaluations, maximization, maxIterations, CancellationToken);


157  return base.Apply();


158  }


159  }


160  }

