code: public int[][] getClusterLabel() {
          if (y == null) {
             throw new IllegalStateException("Neuron cluster labels are not available. Call partition() first.");
          }
  
          int[][] clusterLabels = new int[height][width];
          for (int i = 0, l = 0; i < height; i++) {
              for (int j = 0; j < width; j++) {
                  clusterLabels[i][j] = y[i*width + j];
              }
          }
          return clusterLabels;
      }
docs: Returns the cluster labels for each neuron.  If the neurons have
  not been clustered, throws an Illegal State Exception.