Changeset 14883 for branches/RBFRegression/HeuristicLab.Algorithms.DataAnalysis/3.4/RadialBasisFunctions/KernelFunctions/GaussianKernel.cs

Timestamp:

04/24/17 13:17:43 (7 years ago)

Author:

bwerth

Message:

#2699 checked and reformulated gradient functions for kernels

File:

• branches/RBFRegression/HeuristicLab.Algorithms.DataAnalysis/3.4/RadialBasisFunctions/KernelFunctions/GaussianKernel.cs (modified) (1 diff)

branches/RBFRegression/HeuristicLab.Algorithms.DataAnalysis/3.4/RadialBasisFunctions/KernelFunctions/GaussianKernel.cs

@@ -47 +47 @@
 
     protected override double Get(double norm) {
-      if (Math.Abs(Beta) < double.Epsilon) return 0;
-      return Math.Abs(norm) < double.Epsilon ? 1 : Math.Exp(-norm * norm / (Beta * Beta));
+      if (Math.Abs(Beta) < double.Epsilon) return double.NaN;
+      return Math.Exp(-norm * norm / (Beta * Beta));
     }
 
     protected override double GetGradient(double norm) {
       if (Math.Abs(Beta) < double.Epsilon) return double.NaN;
-      norm *= norm;
-      return 2 * norm * Math.Exp(-norm / (Beta * Beta)) / (Beta * Beta * Beta);
+      return 2 * norm * norm / Math.Pow(Beta, 3) * Math.Exp(-norm * norm / (Beta * Beta));
     }
   }