mple suppose you simply want to get the
      calendar date associated with a time and not the time of
      day. Then you probably do not want round your output.
      Rounding 1992 Dec 31, 13:12:00 to the nearest day
      produces 1993 Jan 1. Thus in this case rounding is probably
      not appropriate.

      However, if you are producing output for plotting using
      Julian Date, seconds past an 1950 or or seconds past
      2000, you will probably want your output rounded so as
      to produce a sm