#region License Information
/* HeuristicLab
* Copyright (C) 2002-2015 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 .
*/
#endregion
using System;
using System.Collections.Generic;
using HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
namespace HeuristicLab.Encodings.LinearLinkageEncoding {
[Item("Group Crossover", "The Group Crossover is implemented as described in Korkmaz, E.E. 2010. Multi-objective Genetic Algorithms for grouping problems. Applied Intelligence 33(2), pp. 179-192.")]
[StorableType("BBFBD498-5A5D-4C86-A936-B05E512A46C6")]
public sealed class GroupCrossover : LinearLinkageCrossover {
[StorableConstructor]
private GroupCrossover(bool deserializing) : base(deserializing) { }
private GroupCrossover(GroupCrossover original, Cloner cloner) : base(original, cloner) { }
public GroupCrossover() { }
public override IDeepCloneable Clone(Cloner cloner) {
return new GroupCrossover(this, cloner);
}
public static LinearLinkage Apply(IRandom random, LinearLinkage p1, LinearLinkage p2) {
var length = p1.Length;
var child = new LinearLinkage(length);
var endNodes = new HashSet();
for (var i = 0; i < length; i++) {
if ((p1[i] == i && p2[i] == i)
|| ((p1[i] == i || p2[i] == i) && random.NextDouble() < 0.5)) {
child[i] = i;
endNodes.Add(i);
}
}
for (var i = 0; i < length; i++) {
if (endNodes.Contains(i)) continue;
var p1End = endNodes.Contains(p1[i]);
var p2End = endNodes.Contains(p2[i]);
if ((p1End && p2End) || (!p1End && !p2End)) {
child[i] = random.NextDouble() < 0.5 ? p1[i] : p2[i];
} else if (p1End) {
child[i] = p1[i];
} else {
child[i] = p2[i];
}
}
child.LinearizeTreeStructures();
return child;
}
protected override LinearLinkage Cross(IRandom random, ItemArray parents) {
if (parents.Length != 2) throw new InvalidOperationException(Name + ": Can only cross exactly two parents.");
return Apply(random, parents[0], parents[1]);
}
}
}