public static Clustering gaussianMeans()

in samoa-api/src/main/java/org/apache/samoa/moa/clusterers/KMeans.java [134:196]
51 lines of code
13 McCabe index (conditional complexity)

  public static Clustering gaussianMeans(Clustering gtClustering, Clustering clustering) {
    ArrayList<CFCluster> microclusters = new ArrayList<CFCluster>();
    for (int i = 0; i < clustering.size(); i++) {
      if (clustering.get(i) instanceof CFCluster) {
        microclusters.add((CFCluster) clustering.get(i));
      }
      else {
        System.out.println("Unsupported Cluster Type:" + clustering.get(i).getClass()
            + ". Cluster needs to extend moa.cluster.CFCluster");
      }
    }
    Cluster[] centers = new Cluster[gtClustering.size()];
    for (int i = 0; i < centers.length; i++) {
      centers[i] = gtClustering.get(i);

    }

    int k = centers.length;
    if (microclusters.size() < k) {
      return new Clustering(new Cluster[0]);
    }

    Clustering kMeansResult = kMeans(centers, microclusters);

    k = kMeansResult.size();
    CFCluster[] res = new CFCluster[k];

    for (CFCluster microcluster : microclusters) {
      // Find closest kMeans cluster
      double minDistance = Double.MAX_VALUE;
      int closestCluster = 0;
      for (int i = 0; i < k; i++) {
        double distance = distance(kMeansResult.get(i).getCenter(), microcluster.getCenter());
        if (distance < minDistance) {
          closestCluster = i;
          minDistance = distance;
        }
      }

      // Add to cluster
      if (res[closestCluster] == null) {
        res[closestCluster] = (CFCluster) microcluster.copy();
      } else {
        res[closestCluster].add(microcluster);
      }
    }

    // Clean up res
    int count = 0;
    for (int i = 0; i < res.length; i++) {
      if (res[i] != null)
        ++count;
    }

    CFCluster[] cleaned = new CFCluster[count];
    count = 0;
    for (int i = 0; i < res.length; i++) {
      if (res[i] != null)
        cleaned[count++] = res[i];
    }

    return new Clustering(cleaned);
  }