# File narray_ext.rb, line 75
  def rank_total(*ranks)
    if ranks.size>0
      idx = []
      ranks.each{|i| idx.push(*i)}
      # ranks is expected to be, e.g., [1, 3..5, 7]
      a = self.shape
      n = 1
      idx.each{|i| n *= a[i]}
      n
    else
      self.total
    end
  end