# File lib/backports/1.9.1/float/round.rb, line 6
    def round_with_digits(ndigits=0)
      ndigits = Backports::coerce_to_int(ndigits)
      case
      when ndigits == 0
        round_without_digits
      when ndigits < 0
        p = 10 ** -ndigits
        p > abs ? 0 : (self / p).round * p
      else
        p = 10 ** ndigits
        prod = self * p
        prod.infinite? || prod.nan? ? self : prod.round.to_f / p
      end
    end