Changeset 13405 for branches/ProblemRefactoring/HeuristicLab.Problems.TestFunctions/3.3/Functions/SchafferF6.cs

Timestamp:

11/26/15 09:56:33 (9 years ago)

Author:

abeham

Message:

#2521: Implemented SchafferF6 test function

File:

• branches/ProblemRefactoring/HeuristicLab.Problems.TestFunctions/3.3/Functions/SchafferF6.cs (copied) (copied from branches/ProblemRefactoring/HeuristicLab.Problems.TestFunctions/3.3/Functions/Rastrigin.cs) (5 diffs)

branches/ProblemRefactoring/HeuristicLab.Problems.TestFunctions/3.3/Functions/SchafferF6.cs

@@ -25 +25 @@
 using HeuristicLab.Data;
 using HeuristicLab.Encodings.RealVectorEncoding;
-using HeuristicLab.Parameters;
 using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
 
 namespace HeuristicLab.Problems.TestFunctions {
   /// <summary>
-  /// 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.
+  /// The generalized Rastrigin function y = 0.5 + (Sin^2(Sqrt(x^2 + y^2)) - 0.5) / (1 + 0.001 * (x^2 + y^2))^2 is a multimodal function that has its optimal value 0 at the origin.
+
   /// </summary
-  [Item("Rastrigin", "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.")]
+  [Item("SchafferF6", "Evaluates the Schaffer F6 function y = 0.5 + (Sin^2(Sqrt(x^2 + y^2)) - 0.5) / (1 + 0.001 * (x^2 + y^2))^2 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.")]
   [StorableClass]
-  public class Rastrigin : SingleObjectiveTestFunction {
+  public class SchafferF6 : SingleObjectiveTestFunction {
     /// <summary>
     /// Returns false as the Rastrigin function is a minimization problem.
@@ -52 +51 @@
     /// </summary>
     public override DoubleMatrix Bounds {
-      get { return new DoubleMatrix(new double[,] { { -5.12, 5.12 } }); }
+      get { return new DoubleMatrix(new double[,] { { -100, 100 } }); }
     }
     /// <summary>
-    /// Gets the minimum problem size (1).
+    /// Gets the minimum problem size (2).
     /// </summary>
     public override int MinimumProblemSize {
-      get { return 1; }
+      get { return 2; }
     }
     /// <summary>
-    /// Gets the (theoretical) maximum problem size (2^31 - 1).
+    /// Gets the maximum problem size (2).
     /// </summary>
     public override int MaximumProblemSize {
-      get { return int.MaxValue; }
-    }
-    /// <summary>
-    /// 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.
-    /// </summary>
-    public ValueParameter<DoubleValue> AParameter {
-      get { return (ValueParameter<DoubleValue>)Parameters["A"]; }
-    }
-    /// <summary>
-    /// 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.
-    /// </summary>
-    public DoubleValue A {
-      get { return AParameter.Value; }
-      set { if (value != null) AParameter.Value = value; }
+      get { return 2; }
     }
 
@@ -85 +71 @@
 
     [StorableConstructor]
-    protected Rastrigin(bool deserializing) : base(deserializing) { }
-    protected Rastrigin(Rastrigin original, Cloner cloner) : base(original, cloner) { }
-    /// <summary>
-    /// Initializes a new instance of the RastriginEvaluator with one parameter (<c>A</c>).
-    /// </summary>
-    public Rastrigin()
-      : base() {
-      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)));
-    }
+    protected SchafferF6(bool deserializing) : base(deserializing) { }
+    protected SchafferF6(SchafferF6 original, Cloner cloner) : base(original, cloner) { }
+    public SchafferF6() : base() { }
 
     public override IDeepCloneable Clone(Cloner cloner) {
-      return new Rastrigin(this, cloner);
+      return new SchafferF6(this, cloner);
     }
 
@@ -104 +84 @@
     /// <param name="point">N-dimensional point for which the test function should be evaluated.</param>
     /// <returns>The result value of the Rastrigin function at the given point.</returns>
-    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);
+    public static double Apply(RealVector point) {
+      if (point.Length != 2) throw new ArgumentException("The SchafferF6 can only be evaluated for two dimenional vectors");
+      var sumSquare = point[0] * point[0] + point[1] * point[1];
+      var sin = Math.Sin(Math.Sqrt(sumSquare));
+      var nom = sin * sin - 0.5;
+      var denom = (1 + 0.001 * sumSquare) * (1 + 0.001 * sumSquare);
+      return 0.5 + nom / denom;
     }
 
@@ -120 +100 @@
     /// <returns>The result value of the Rastrigin function at the given point.</returns>
     public override double Evaluate(RealVector point) {
-      return Apply(point, A.Value);
+      return Apply(point);
     }
   }