source: branches/HeuristicLab.BinPacking/HeuristicLab.Problems.BinPacking/3.3/Encodings/MultiComponentVector/SequenceBasedMultiComponentVectorCrossover.cs @ 16003

#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2015 Joseph Helm and Heuristic and Evolutionary Algorithms Laboratory (HEAL)
 *
 * This file is part of HeuristicLab.
 *
 * HeuristicLab is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * HeuristicLab is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
 */
#endregion

using System;
using HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;

namespace HeuristicLab.Encodings.PackingEncoding.MultiComponentVector {
  [Item("Sequence Based Multi Component Vector Crossover", "An operator which crosses two MultiComponentVector representations. The applied strategy is based on the SBX crossover proposed by Potvin.")]
  [StorableClass]
  public class SequenceBasedMultiComponentVectorCrossover :  MultiComponentVectorCrossover {
    [StorableConstructor]
    protected SequenceBasedMultiComponentVectorCrossover (bool deserializing) : base(deserializing) { }
    protected SequenceBasedMultiComponentVectorCrossover (SequenceBasedMultiComponentVectorCrossover  original, Cloner cloner) : base(original, cloner) { }
    public SequenceBasedMultiComponentVectorCrossover ()
      : base() {
    }
    public override IDeepCloneable Clone(Cloner cloner) {
      return new SequenceBasedMultiComponentVectorCrossover (this, cloner);
    }

    public override MultiComponentVectorEncoding Cross(IRandom random, MultiComponentVectorEncoding parent1, MultiComponentVectorEncoding parent2) {
      MultiComponentVectorEncoding child = new MultiComponentVectorEncoding();
      int nrOfItems = parent1.NrOfItems;
      bool[] itemAlreadyAssigned = new bool[nrOfItems];

      bool useParent2 = false;
      int nrOfBins = parent1.NrOfBins > parent2.NrOfBins ? parent2.NrOfBins : parent1.NrOfBins;


      for (int binNr = 0; binNr < nrOfBins; binNr++) {
        MultiComponentVectorEncoding currentParent1 = useParent2 ? parent2 : parent1;
        MultiComponentVectorEncoding currentParent2 = useParent2 ? parent1 : parent2;


        var newBin = new ItemList<PackingInformation>();
        double crossPointPercent = 0;

        int nrOfItems1 = currentParent1.PackingInformations[binNr].Count;
        if (nrOfItems1 > 0) {
          double crossPoint1 = random.Next(nrOfItems1);
          crossPointPercent = crossPoint1 / nrOfItems1;
          for (int i = 0; i < crossPoint1; i++) {
            PackingInformation pi = new PackingInformation(currentParent1.PackingInformations[binNr][i]);
            if (!itemAlreadyAssigned[pi.ItemID]) {
              itemAlreadyAssigned[pi.ItemID] = true;
              newBin.Add(new PackingInformation(pi));
            }
          }
        }

        int nrOfItems2 = currentParent2.PackingInformations[binNr].Count;
        if (nrOfItems2 > 0) {
          int crossPoint2 = Convert.ToInt32(nrOfItems2 * crossPointPercent);
          for (int i = crossPoint2; i < nrOfItems2; i++) {
            PackingInformation pi = new PackingInformation(currentParent2.PackingInformations[binNr][i]);
            if (!itemAlreadyAssigned[pi.ItemID]) {
              itemAlreadyAssigned[pi.ItemID] = true;
              newBin.Add(new PackingInformation(pi));
            }
          }
        }

        child.PackingInformations[binNr] = newBin;
        useParent2 = !useParent2;
      }

      for (int itemID = 0; itemID < nrOfItems; itemID++) {
        if (!itemAlreadyAssigned[itemID])
          child.PackingInformations[0].Add(new PackingInformation(itemID, random.Next(2) == 0 ? true : false));
      }
      
      return child;
    }       
  }
}