Changeset 10109 for branches/HeuristicLab.Analysis.AlgorithmBehavior/HeuristicLab.Analysis.AlgorithmBehavior.Analyzers/3.3/DistanceMatrixToPoints.cs

Timestamp:

11/05/13 23:57:18 (11 years ago)

Author:

ascheibe

Message:

#1886 fixed other MDS and added more unit tests

File:

• branches/HeuristicLab.Analysis.AlgorithmBehavior/HeuristicLab.Analysis.AlgorithmBehavior.Analyzers/3.3/DistanceMatrixToPoints.cs (modified) (2 diffs)

branches/HeuristicLab.Analysis.AlgorithmBehavior/HeuristicLab.Analysis.AlgorithmBehavior.Analyzers/3.3/DistanceMatrixToPoints.cs

@@ -33 +33 @@
      *   
      */
-    public static double[][] ConvertDistanceMatrixToPoints(double[][] dm) {
+    public static double[][] ConvertDistanceMatrixToPoints(double[][] dm, int k = 2) {
       double[][] points = new double[dm.Length][];
       double[,] m = new double[dm.Length, dm.Length];
@@ -45 +45 @@
       }
 
-      //QR decomposition to get the upper part for smatrixevd
-      double[] tau;
-      double[,] r;
-      alglib.rmatrixqr(ref m, dm.Length, dm.Length, out tau);
-      alglib.rmatrixqrunpackr(m, dm.Length, dm.Length, out r);
-
-      bool res = alglib.smatrixevd(r, dm.Length, 1, true, out q, out v);
+      bool res = alglib.smatrixevd(m, dm.Length, 1, true, out q, out v);
       if (!res) throw new Exception("Eigenvalue computation did not converge!");
 
-      int zeroCnt = q.Count(x => x.IsAlmost(0) || x < 0.0);
-      for (int i = 0; i < dm.Length; i++) {
-        points[i] = new double[dm.Length - zeroCnt];
-      }
-
-      int pi = 0;
-      for (int i = 0; i < dm.Length; i++) {
-        if (!q[i].IsAlmost(0.0) && q[i] > 0.0) {
-          for (int j = 0; j < dm.Length; j++) {
-            points[j][pi] = Math.Sqrt(q[i]) * v[j, i];
-          }
-          pi++;
+      //TODO: this should also work without allocating memory for ev and evec
+      double[] ev = new double[k];
+      double[][] evec = new double[dm.Length][];
+      AllocArray(evec, k);
+      Array.Copy(q, q.Length - k, ev, 0, k);
+      for (int i = 0; i < k; i++) {
+        for (int j = 0; j < dm.Length; j++) {
+          evec[j][i] = v[j, i + (q.Length - k)];
         }
       }
 
+      double k1 = SumIfLZero(ev);
+      if (k1 < k) {
+        throw new Exception("Zero-eigenvalues detected. This leads to a degenerate point set. Use constants. ");
+        //TODO: handling of this case; implement adding of constants
+      }
+
+      AllocArray(points, k);
+      for (int i = 0; i < k; i++) {
+        for (int j = 0; j < dm.Length; j++) {
+          points[j][i] = Math.Sqrt(ev[i]) * evec[j][i];
+        }
+      }
       return points;
     }