#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.Data;
using HeuristicLab.Encodings.RealVectorEncoding;
using HeuristicLab.Parameters;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
namespace HeuristicLab.Problems.TestFunctions {
///
/// The generalized Rastrigin function y = Sum((x_i)^2 + A * (1 - Cos(2pi*x_i))) is a highly multimodal function that has its optimal value 0 at the origin.
/// It is implemented as described in Eiben, A.E. and Smith, J.E. 2003. Introduction to Evolutionary Computation. Natural Computing Series, Springer-Verlag Berlin Heidelberg.
///
/// Returns false as the Rastrigin function is a minimization problem.
///
public override bool Maximization {
get { return false; }
}
///
/// Gets the optimum function value (0).
///
public override double BestKnownQuality {
get { return 0; }
}
///
/// Gets the lower and upper bound of the function.
///
public override DoubleMatrix Bounds {
get { return new DoubleMatrix(new double[,] { { -5.12, 5.12 } }); }
}
///
/// Gets the minimum problem size (1).
///
public override int MinimumProblemSize {
get { return 1; }
}
///
/// Gets the (theoretical) maximum problem size (2^31 - 1).
///
public override int MaximumProblemSize {
get { return int.MaxValue; }
}
///
/// The parameter A is a parameter of the objective function y = Sum((x_i)^2 + A * (1 - Cos(2pi*x_i))). Default is A = 10.
///
public ValueParameter AParameter {
get { return (ValueParameter)Parameters["A"]; }
}
///
/// The parameter A is a parameter of the objective function y = Sum((x_i)^2 + A * (1 - Cos(2pi*x_i))). Default is A = 10.
///
public DoubleValue A {
get { return AParameter.Value; }
set { if (value != null) AParameter.Value = value; }
}
public override RealVector GetBestKnownSolution(int dimension) {
return new RealVector(dimension);
}
///
/// Initializes a new instance of the RastriginEvaluator with one parameter (A).
///
public RastriginEvaluator()
: base() {
Parameters.Add(new ValueParameter("A", "The parameter A is a parameter of the objective function y = Sum((x_i)^2 + A * (1 - Cos(2pi*x_i))). Default is A = 10.", new DoubleValue(10)));
}
///
/// Evaluates the test function for a specific .
///
/// N-dimensional point for which the test function should be evaluated.
/// The result value of the Rastrigin function at the given point.
public static double Apply(RealVector point, double a) {
double result = a * point.Length;
for (int i = 0; i < point.Length; i++) {
result += point[i] * point[i];
result -= a * Math.Cos(2 * Math.PI * point[i]);
}
return (result);
}
///
/// Evaluates the test function for a specific .
///
/// Calls .
/// N-dimensional point for which the test function should be evaluated.
/// The result value of the Rastrigin function at the given point.
protected override double EvaluateFunction(RealVector point) {
return Apply(point, A.Value);
}
}
}