Changeset 13784 for trunk/sources/HeuristicLab.Algorithms.DataAnalysis/3.4/GaussianProcess/CovarianceFunctions/CovariancePeriodic.cs

Timestamp:

04/22/16 13:47:35 (8 years ago)

Author:

pfleck

Message:

#2591 Made the creation of a GaussianProcessModel faster by avoiding additional iterators during calculation of the hyperparameter gradients.
The gradients of the hyperparameters are now calculated in one sweep and returned as IList, instead of returning an iterator (with yield return).
This avoids a large amount of Move-calls of the iterator, especially for covariance functions with a lot of hyperparameters.
Besides, the signature of the CovarianceGradientFunctionDelegate is changed, to return an IList instead of an IEnumerable to avoid unnececary ToList or ToArray calls.

File:

• trunk/sources/HeuristicLab.Algorithms.DataAnalysis/3.4/GaussianProcess/CovarianceFunctions/CovariancePeriodic.cs (modified) (3 diffs)

trunk/sources/HeuristicLab.Algorithms.DataAnalysis/3.4/GaussianProcess/CovarianceFunctions/CovariancePeriodic.cs

@@ -22 +22 @@
 using System;
 using System.Collections.Generic;
-using System.Linq;
 using HeuristicLab.Common;
 using HeuristicLab.Core;
@@ -117 +116 @@
     }
 
-    public ParameterizedCovarianceFunction GetParameterizedCovarianceFunction(double[] p, int[]columnIndices) {
+    public ParameterizedCovarianceFunction GetParameterizedCovarianceFunction(double[] p, int[] columnIndices) {
       double inverseLength, period, scale;
       GetParameterValues(p, out scale, out period, out inverseLength);
@@ -145 +144 @@
     }
 
-
-    private static IEnumerable<double> GetGradient(double[,] x, int i, int j, int[] columnIndices, double scale, double period, double inverseLength,
+    private static IList<double> GetGradient(double[,] x, int i, int j, int[] columnIndices, double scale, double period, double inverseLength,
       bool fixedInverseLength, bool fixedPeriod, bool fixedScale) {
       double k = i == j ? 0.0 : Math.PI * GetDistance(x, x, i, j, columnIndices) / period;
       double gradient = Math.Sin(k) * inverseLength;
       gradient *= gradient;
-      if (!fixedInverseLength) yield return 4.0 * scale * Math.Exp(-2.0 * gradient) * gradient;
+      var g = new List<double>(3);
+      if (!fixedInverseLength) 
+        g.Add(4.0 * scale * Math.Exp(-2.0 * gradient) * gradient);
       if (!fixedPeriod) {
         double r = Math.Sin(k) * inverseLength;
-        yield return 2.0 * k * scale * Math.Exp(-2 * r * r) * Math.Sin(2 * k) * inverseLength * inverseLength;
+        g.Add(2.0 * k * scale * Math.Exp(-2 * r * r) * Math.Sin(2 * k) * inverseLength * inverseLength);
       }
       if (!fixedScale)
-        yield return 2.0 * scale * Math.Exp(-2 * gradient);
-
+        g.Add(2.0 * scale * Math.Exp(-2 * gradient));
+      return g;
     }