#region License Information
/* HeuristicLab
* Copyright (C) 2002-2010 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 HeuristicLab.Core;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
namespace HeuristicLab.Permutation {
///
/// Performs a cross over permutation between two permutation arrays by taking
/// the entries with the same index (starting at position 0) from both parents
/// (minding already inserted values).
///
/// It is implemented as described in Moraglio, A. and Poli, R. 2005. Topological crossover for the permutation representation. In Proceedings of the 2005 Workshops on Genetic and Evolutionary Computation.
///
/// First take the value at position 0 from parent1 then take the value at position 0
/// from parent2 if it has not already been inserted, afterwards take the value at position 1 from
/// parent1 if it has not already been inserted, then from parent2 and so on.
[Item("AbsolutePositionTopologicalCrossover", @"An operator which performs a cross over permutation between two permutation arrays by taking the
entries with the same index (starting at position 0) from both parents
(minding already inserted values).")]
[EmptyStorableClass]
[Creatable("Test")]
public class AbsolutePositionTopologicalCrossover : PermutationCrossover {
///
/// Performs a cross over permutation of and
/// by taking the values from both parents one by one with the same index starting at position 0.
///
/// First take the value at position 0 from parent1 then take the value at position 0
/// from parent2 if it has not already been inserted, afterwards take the value at position 1 from
/// parent1 if it has not already been inserted, then from parent2 and so on.
/// Thrown when and are not of equal length.
/// The random number generator.
/// The parent scope 1 to cross over.
/// The parent scope 2 to cross over.
/// The created cross over permutation as int array.
public static Permutation Apply(IRandom random, Permutation parent1, Permutation parent2) {
if (parent1.Length != parent2.Length) throw new ArgumentException("AbsolutePositionTopologicalCrossover: The parent permutations are of unequal length.");
int length = parent1.Length;
int[] result = new int[length];
bool[] numberCopied = new bool[length];
int index;
index = 0;
for (int i = 0; i < length; i++) { // copy numbers from both parent permutations
if (!numberCopied[parent1[i]]) {
result[index] = parent1[i];
numberCopied[parent1[i]] = true;
index++;
}
if (!numberCopied[parent2[i]]) {
result[index] = parent2[i];
numberCopied[parent2[i]] = true;
index++;
}
}
return new Permutation(result);
}
///
/// Performs an absolute position topological crossover operation for two given parent permutations.
///
/// Thrown if there are not exactly two parents.
/// A random number generator.
/// An array containing the two permutations that should be crossed.
/// The newly created permutation, resulting from the crossover operation.
protected override Permutation Cross(IRandom random, ItemArray parents) {
if (parents.Length != 2) throw new InvalidOperationException("ERROR in AbsolutePositionTopologicalCrossover: The number of parents is not equal to 2");
return Apply(random, parents[0], parents[1]);
}
}
}