;+
;
; @file_comments
; gives yyyymmdd date equivalent of a Julian day
; This is the inverse of the function <pro>date2jul</pro>.
;
; @categories
; Calendar
;
; @param jday {in}{required} {type=long or double, scalar or array}
; Julian day
;
; @keyword MONTH
; Set this keyword equal to a named variable that will receive a
; longword integer or longword integer array representing the number of
; the desired month (1 = January, ..., 12 = December). 
;
; @keyword DAY
; Set this keyword equal to a named variable that will receive a
; longword integer or longword integer array representing the number of
; the day of the month (1-31).  
;
; @keyword YEAR
; Set this keyword equal to a named variable that will receive a
; longword integer or longword integer array representing the number of
; the desired year (e.g., 1994).  
;
; @keyword HOUR
; Set this keyword equal to a named variable that will receive a
; longword integer or longword integer array representing the number of
; the hour of the day (0-23).  
; 
; @keyword MINUTE
; Set this keyword equal to a named variable that will receive a
; longword integer or longword integer array representing the number of
; the minute of the hour (0-59).  
;  
; @keyword SECOND
; Set this keyword equal to a named variable that will receive a
; double-precision floating-point value or a double-precision
; floating-point array representing the number of the second of the
; minute (0-59).
;
; @returns
; the date: longword integer with yyyymmdd format or double-precision
; floating-point with yyyymmdd.xx where xx is the fraction of the day
; (xx=0 at 0am and 5 at 12am) 
;
; @restrictions
; Input param must be longword integer or double-precision floating-point
; 
; @examples
;
;   IDL> print, jul2date(julday(12,23,1999))
;     19991223
;   IDL> print, jul2date(julday(12,23,1999,12,0,0))
;        19991224.
;   IDL> print, jul2date(julday(12,23,1999,12,0,0)), format='(f11.2)'
; 19991223.50
;   IDL> print, jul2date(julday(12,23,1999,0,0,0)), format='(f11.2)'
; 19991223.00
;
; @history
; Sebastien Masson (smasson\@lodyc.jussieu.fr)
;                       June 2005
;
; @version
; $Id$
;
;-
function jul2date, jday, MONTH=month, DAY=day, YEAR=year $
                 , HOUR=hour, MINUTE=minute, SECOND=second
;
  compile_opt idl2, strictarrsubs
;
  sztype = size(jday, /type)
  IF sztype NE 3 AND sztype NE 5 AND sztype LT 13 THEN BEGIN
    dummy = report('Beware of input type, julian date must be long or double')
    stop
  ENDIF
;
  caldat, jday, month, day, year, hour, minute, second
;
  res = (10000L*year + 100L*month + day)*(year GE 0) $
        +( 10000L*year - 100L*month - day)*(year LT 0)
;
  IF sztype NE 5 THEN return, long(res) $
  ELSE return, double(res) + (hour / 24.0d0) + (minute/1440.0d0) + (second / 86400.0d0)

end