code: public Assignments cluster(Matrix matrix, 
                                 int numClusters,
                                 Properties props) {
          LOGGER.warning("Link clustering does not take a specified number of " +
                         "clusters.  Clustering the matrix anyway.");
          return cluster(matrix, props);
      }
docs: <i>Ignores the specified number of clusters</i> and returns the
  clustering solution according to the partition density.
  
  @param numClusters this parameter is ignored.
  
  @throws IllegalArgumentException if {@code matrix} is not square, or is
  not an instance of {@link SparseMatrix}