Converts from Rata Die (R.D. number) to Gregorian date.
See the footnote on page 384 of ``Calendrical Calculations, Part II:
Three Historical Calendars'' by E. M. Reingold, N. Dershowitz, and S. M.
Clamen, Software--Practice and Experience, Volume 23, Number 4
(April, 1993), pages 383-404 for an explanation.
Converts from Rata Die (R.D. number) to Gregorian date. See the footnote on page 384 of ``Calendrical Calculations, Part II: Three Historical Calendars'' by E. M. Reingold, N. Dershowitz, and S. M. Clamen, Software--Practice and Experience, Volume 23, Number 4 (April, 1993), pages 383-404 for an explanation.