Changeset 8623 for trunk/sources/HeuristicLab.Problems.DataAnalysis/3.4/Implementation/Classification/ThresholdCalculators/NormalDistributionCutPointsThresholdCalculator.cs

Timestamp:

09/10/12 17:13:46 (12 years ago)

Author:

gkronber

Message:

#1902 implemented LS Gaussian Process classification

File:

• trunk/sources/HeuristicLab.Problems.DataAnalysis/3.4/Implementation/Classification/ThresholdCalculators/NormalDistributionCutPointsThresholdCalculator.cs (modified) (2 diffs)

trunk/sources/HeuristicLab.Problems.DataAnalysis/3.4/Implementation/Classification/ThresholdCalculators/NormalDistributionCutPointsThresholdCalculator.cs

@@ -107 +107 @@
         double maxDensityClassValue = -1;
         foreach (var classValue in originalClasses) {
-          double density = NormalDensity(m, classMean[classValue], classStdDev[classValue]);
+          double density = LogNormalDensity(m, classMean[classValue], classStdDev[classValue]);
           if (density > maxDensity) {
             maxDensity = density;
@@ -139 +139 @@
     }
 
-    private static double NormalDensity(double x, double mu, double sigma) {
-      if (sigma.IsAlmost(0.0)) {
-        if (x.IsAlmost(mu)) return 1.0; else return 0.0;
-      } else {
-        return (1.0 / Math.Sqrt(2.0 * Math.PI * sigma * sigma)) * Math.Exp(-((x - mu) * (x - mu)) / (2.0 * sigma * sigma));
-      }
+    private static double LogNormalDensity(double x, double mu, double sigma) {
+      return -0.5 * Math.Log(2.0 * Math.PI * sigma * sigma) - ((x - mu) * (x - mu)) / (2.0 * sigma * sigma);
     }