# File lib/ai4r/clusterers/single_linkage.rb, line 158
      def build_clusters_from_index_clusters(index_clusters)
        @distance_matrix = nil
        return index_clusters.collect do |index_cluster|
          Ai4r::Data::DataSet.new(:data_labels => @data_set.data_labels,
            :data_items => index_cluster.collect {|i| @data_set.data_items[i]})
        end
      end