1 | #region License Information
|
---|
2 | /* HeuristicLab
|
---|
3 | * Copyright (C) 2002-2010 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 HeuristicLab.Core;
|
---|
24 | using HeuristicLab.Data;
|
---|
25 | using HeuristicLab.Encodings.RealVectorEncoding;
|
---|
26 | using HeuristicLab.Parameters;
|
---|
27 | using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
|
---|
28 |
|
---|
29 | namespace HeuristicLab.Problems.TestFunctions {
|
---|
30 | /// <summary>
|
---|
31 | /// 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.
|
---|
32 | /// 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.
|
---|
33 | /// </summary
|
---|
34 | [Item("RastriginEvaluator", "Evaluates the generalized Rastrigin function y = Sum((x_i)^2 + A * (1 - Cos(2pi*x_i))) on a given point. The optimum of this function is 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.")]
|
---|
35 | [StorableClass]
|
---|
36 | public class RastriginEvaluator : SingleObjectiveTestFunctionProblemEvaluator {
|
---|
37 | /// <summary>
|
---|
38 | /// Returns false as the Rastrigin function is a minimization problem.
|
---|
39 | /// </summary>
|
---|
40 | public override bool Maximization {
|
---|
41 | get { return false; }
|
---|
42 | }
|
---|
43 | /// <summary>
|
---|
44 | /// Gets the optimum function value (0).
|
---|
45 | /// </summary>
|
---|
46 | public override double BestKnownQuality {
|
---|
47 | get { return 0; }
|
---|
48 | }
|
---|
49 | /// <summary>
|
---|
50 | /// Gets the lower and upper bound of the function.
|
---|
51 | /// </summary>
|
---|
52 | public override DoubleMatrix Bounds {
|
---|
53 | get { return new DoubleMatrix(new double[,] { { -5.12, 5.12 } }); }
|
---|
54 | }
|
---|
55 | /// <summary>
|
---|
56 | /// Gets the minimum problem size (1).
|
---|
57 | /// </summary>
|
---|
58 | public override int MinimumProblemSize {
|
---|
59 | get { return 1; }
|
---|
60 | }
|
---|
61 | /// <summary>
|
---|
62 | /// Gets the (theoretical) maximum problem size (2^31 - 1).
|
---|
63 | /// </summary>
|
---|
64 | public override int MaximumProblemSize {
|
---|
65 | get { return int.MaxValue; }
|
---|
66 | }
|
---|
67 | /// <summary>
|
---|
68 | /// 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.
|
---|
69 | /// </summary>
|
---|
70 | public ValueParameter<DoubleValue> AParameter {
|
---|
71 | get { return (ValueParameter<DoubleValue>)Parameters["A"]; }
|
---|
72 | }
|
---|
73 | /// <summary>
|
---|
74 | /// 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.
|
---|
75 | /// </summary>
|
---|
76 | public DoubleValue A {
|
---|
77 | get { return AParameter.Value; }
|
---|
78 | set { if (value != null) AParameter.Value = value; }
|
---|
79 | }
|
---|
80 |
|
---|
81 | public override RealVector GetBestKnownSolution(int dimension) {
|
---|
82 | return new RealVector(dimension);
|
---|
83 | }
|
---|
84 |
|
---|
85 | /// <summary>
|
---|
86 | /// Initializes a new instance of the RastriginEvaluator with one parameter (<c>A</c>).
|
---|
87 | /// </summary>
|
---|
88 | public RastriginEvaluator()
|
---|
89 | : base() {
|
---|
90 | Parameters.Add(new ValueParameter<DoubleValue>("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)));
|
---|
91 | }
|
---|
92 |
|
---|
93 | /// <summary>
|
---|
94 | /// Evaluates the test function for a specific <paramref name="point"/>.
|
---|
95 | /// </summary>
|
---|
96 | /// <param name="point">N-dimensional point for which the test function should be evaluated.</param>
|
---|
97 | /// <returns>The result value of the Rastrigin function at the given point.</returns>
|
---|
98 | public static double Apply(RealVector point, double a) {
|
---|
99 | double result = a * point.Length;
|
---|
100 | for (int i = 0; i < point.Length; i++) {
|
---|
101 | result += point[i] * point[i];
|
---|
102 | result -= a * Math.Cos(2 * Math.PI * point[i]);
|
---|
103 | }
|
---|
104 | return (result);
|
---|
105 | }
|
---|
106 |
|
---|
107 | /// <summary>
|
---|
108 | /// Evaluates the test function for a specific <paramref name="point"/>.
|
---|
109 | /// </summary>
|
---|
110 | /// <remarks>Calls <see cref="Apply"/>.</remarks>
|
---|
111 | /// <param name="point">N-dimensional point for which the test function should be evaluated.</param>
|
---|
112 | /// <returns>The result value of the Rastrigin function at the given point.</returns>
|
---|
113 | protected override double EvaluateFunction(RealVector point) {
|
---|
114 | return Apply(point, A.Value);
|
---|
115 | }
|
---|
116 | }
|
---|
117 | }
|
---|