jd_to_civil

# File lib/date.rb, line 417
    def jd_to_civil(jd, sg=GREGORIAN) # :nodoc:
      if jd < sg
        a = jd
      else
        x = ((jd - 1867216.25) / 36524.25).floor
        a = jd + 1 + x - (x / 4.0).floor
      end
      b = a + 1524
      c = ((b - 122.1) / 365.25).floor
      d = (365.25 * c).floor
      e = ((b - d) / 30.6001).floor
      dom = b - d - (30.6001 * e).floor
      if e <= 13
        m = e - 1
        y = c - 4716
      else
        m = e - 13
        y = c - 4715
      end
      return y, m, dom
    end