# File lib/ai4r/clusterers/diana.rb, line 118
      def max_distance_difference(cluster_to_split, splinter_cluster)
        max_diff = -1.0/0
        max_diff_index = 0
        cluster_to_split.data_items.each_with_index do |item, index|
          dist_a = distance_sum(item, cluster_to_split) / (cluster_to_split.data_items.length-1)
          dist_b = distance_sum(item, splinter_cluster) / (splinter_cluster.data_items.length)
          dist_diff = dist_a - dist_b
          max_diff, max_diff_index = dist_diff, index if dist_diff > max_diff
        end
        return max_diff, max_diff_index
      end