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.Collections.Generic;


24  using System.Linq;


25  using HeuristicLab.Common;


26  using HeuristicLab.Core;


27  using HeuristicLab.Data;


28  using HeuristicLab.Encodings.BinaryVectorEncoding;


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


30 


31  namespace HeuristicLab.Algorithms.ScatterSearch.Knapsack {


32  /// <summary>


33  /// An operator that relinks paths between knapsack solutions.


34  /// </summary>


35  [Item("KnapsackPathRelinker", "An operator that relinks paths between knapsack solutions.")]


36  [StorableClass]


37  public sealed class KnapsackPathRelinker : PathRelinker {


38  [StorableConstructor]


39  private KnapsackPathRelinker(bool deserializing) : base(deserializing) { }


40  private KnapsackPathRelinker(KnapsackPathRelinker original, Cloner cloner) : base(original, cloner) { }


41  public KnapsackPathRelinker()


42  : base() {


43  ParentsParameter.ActualName = "KnapsackSolution";


44  }


45 


46  public override IDeepCloneable Clone(Cloner cloner) {


47  return new KnapsackPathRelinker(this, cloner);


48  }


49 


50  public static ItemArray<IItem> Apply(IItem initiator, IItem guide, PercentValue n) {


51  if (!(initiator is BinaryVector)  !(guide is BinaryVector))


52  throw new ArgumentException("Cannot relink path because one of the provided solutions or both have the wrong type.");


53  if (n.Value <= 0.0)


54  throw new ArgumentException("RelinkingAccuracy must be greater than 0.");


55 


56  var v1 = initiator.Clone() as BinaryVector;


57  var v2 = guide as BinaryVector;


58 


59  if (v1.Length != v2.Length)


60  throw new ArgumentException("The solutions are of different length.");


61 


62  var solutions = new List<BinaryVector>();


63  for (int i = 0; i < v1.Length; i++)


64  if (v1[i] != v2[i]) {


65  v1[i] = v2[i];


66  solutions.Add(v1.Clone() as BinaryVector);


67  }


68 


69  var selection = new List<IItem>();


70  if (solutions.Count > 0) {


71  var noSol = (int)Math.Round(solutions.Count * n.Value);


72  if (noSol <= 0) noSol++;


73  var stepSize = (double)solutions.Count / (double)noSol;


74  for (int i = 0; i < noSol; i++)


75  selection.Add(solutions.ElementAt((int)Math.Round((i + 1) * stepSize  stepSize * 0.5)));


76  }


77 


78  return new ItemArray<IItem>(selection);


79  }


80 


81  protected override ItemArray<IItem> Relink(ItemArray<IItem> parents, PercentValue n) {


82  if (parents.Length != 2)


83  throw new ArgumentException("The number of parents is not equal to 2.");


84  return Apply(parents[0], parents[1], n);


85  }


86  }


87  }

