code: public Assignments cluster(Matrix matrix, int numClusters, 
                                  Method clusterMethod,
                                  Criterion criterionMethod) {
          try {
              String clmethod = clusterMethod.getClutoName();
              String crtmethod = criterionMethod.getClutoName();
              return ClutoWrapper.cluster(matrix, clmethod,
                                          crtmethod, numClusters);
          } catch (IOException ioe) {
              throw new IOError(ioe);
          }
      }
docs: Clusters the set of rows in the given {@code Matrix} into a specified
  number of clusters using the specified CLUTO clustering method.
  
  @param matrix the {@link Matrix} containing data points to cluster
  @param numClusters the number of clusters to generate
  @param clusterMethod the method by which cluto should cluster the rows
  
  @return an array of {@link Assignment} instances that indicate zero or
  more clusters to which each row belongs.