# File lib/ai4r/som/som.rb, line 73
      def find_bmu(input)
        bmu = @nodes.first
        dist = bmu.distance_to_input input
        @nodes[1..-1].each do |node|
          tmp_dist = node.distance_to_input(input)
          if tmp_dist <= dist
            dist = tmp_dist
            bmu = node
          end
        end
        [bmu, dist]
      end