1  #region License Information


2  /* HeuristicLab


3  * Copyright (C) 20022011 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.Collections.Generic;


24  using System.Linq;


25  using HeuristicLab.Common;


26  using HeuristicLab.Core;


27  using HeuristicLab.Data;


28  using HeuristicLab.Optimization;


29  using HeuristicLab.Parameters;


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


31  using HeuristicLab.PluginInfrastructure;


32 


33  namespace HeuristicLab.Selection {


34  /// <summary>


35  /// The generalized rank selection operator selects qualities by rank with a varying focus on better qualities. It is implemented as described in Tate, D. M. and Smith, A. E. 1995. A genetic approach to the quadratic assignment problem. Computers & Operations Research, vol. 22, pp. 7383.


36  /// </summary>


37  [Item("GeneralizedRankSelector", "The generalized rank selection operator selects qualities by rank with a varying focus on better qualities. It is implemented as described in Tate, D. M. and Smith, A. E. 1995. A genetic approach to the quadratic assignment problem. Computers & Operations Research, vol. 22, pp. 7383.")]


38  [StorableClass]


39  public sealed class GeneralizedRankSelector : StochasticSingleObjectiveSelector, ISelector {


40 


41  public IValueLookupParameter<DoubleValue> PressureParameter {


42  get { return (IValueLookupParameter<DoubleValue>)Parameters["Pressure"]; }


43  }


44 


45  [StorableConstructor]


46  private GeneralizedRankSelector(bool deserializing) : base(deserializing) { }


47  private GeneralizedRankSelector(GeneralizedRankSelector original, Cloner cloner) : base(original, cloner) { }


48  public GeneralizedRankSelector()


49  : base() {


50  Parameters.Add(new ValueLookupParameter<DoubleValue>("Pressure", "The selection pressure that is applied, must lie in the interval [1;infinity). A pressure of 1 equals random selection, higher pressure values focus on selecting better qualities.", new DoubleValue(2)));


51  }


52 


53  public override IDeepCloneable Clone(Cloner cloner) {


54  return new GeneralizedRankSelector(this, cloner);


55  }


56 


57  protected override IScope[] Select(List<IScope> scopes) {


58  int count = NumberOfSelectedSubScopesParameter.ActualValue.Value;


59  bool copy = CopySelectedParameter.Value.Value;


60  IRandom random = RandomParameter.ActualValue;


61  bool maximization = MaximizationParameter.ActualValue.Value;


62  ItemArray<DoubleValue> qualities = QualityParameter.ActualValue;


63  IScope[] selected = new IScope[count];


64  double pressure = PressureParameter.ActualValue.Value;


65 


66  var ordered = qualities.Select((x, index) => new IndexValuePair(index, x.Value)).OrderBy(x => x.Value).ToList();


67  if (maximization) ordered.Reverse();


68 


69  int m = scopes.Count;


70  for (int i = 0; i < count; i++) {


71  double rand = 1 + random.NextDouble() * (Math.Pow(m, 1.0 / pressure)  1);


72  int selIdx = (int)Math.Floor(Math.Pow(rand, pressure)  1);


73 


74  if (copy) {


75  selected[i] = (IScope)scopes[ordered[selIdx].Index].Clone();


76  } else {


77  int idx = ordered[selIdx].Index;


78  selected[i] = scopes[idx];


79  scopes.RemoveAt(idx);


80  ordered.RemoveAt(selIdx);


81  for (int j = 0; j < ordered.Count; j++) {


82  var o = ordered[j];


83  if (o.Index > idx) ordered[j] = o.DecrementIndex();


84  }


85  m;


86  }


87  }


88  return selected;


89  }


90 


91  [NonDiscoverableType]


92  private struct IndexValuePair {


93  private int index;


94  internal int Index { get { return index; } }


95  private double value;


96  internal double Value { get { return value; } }


97 


98  internal IndexValuePair(int index, double value) {


99  this.index = index;


100  this.value = value;


101  }


102 


103  internal IndexValuePair DecrementIndex() {


104  this.index;


105  return this;


106  }


107  }


108  }


109  }

