--- trunk/IOIPSL/Calendar/ymds2ju.f	2014/03/26 18:16:05	92
+++ trunk/IOIPSL/Calendar/ymds2ju.f	2014/04/01 15:50:48	93
@@ -6,19 +6,70 @@
 
   SUBROUTINE ymds2ju (year, month, day, sec, julian)
 
-    use calendar, only: un_jour
-    use ymds2ju_internal_m
+    ! Converts year, month, day and seconds into a julian day
+
+    ! In 1968 in a letter to the editor of Communications of the ACM
+    ! (CACM, volume 11, number 10, October 1968, p.657) Henry F. Fliegel
+    ! and Thomas C. Van Flandern presented such an algorithm.
+
+    ! See also: http://www.magnet.ch/serendipity/hermetic/cal_stud/jdn.htm
+
+    ! In the case of the Gregorian calendar we have chosen to use
+    ! the Lilian day numbers. This is the day counter which starts
+    ! on the 15th October 1582.
+    ! This is the day at which Pope Gregory XIII introduced the
+    ! Gregorian calendar.
+    ! Compared to the true Julian calendar, which starts some
+    ! 7980 years ago, the Lilian days are smaler and are dealt with
+    ! easily on 32 bit machines. With the true Julian days you can only
+    ! the fraction of the day in the real part to a precision of
+    ! a 1/4 of a day with 32 bits.
+
+    USE calendar, ONLY: lock_unan, un_jour
+    USE ioconf_calendar_m, ONLY: mon_len, un_an
 
     INTEGER, INTENT(IN):: year, month, day
     REAL, INTENT(IN):: sec
     REAL, INTENT(OUT):: julian
 
+    ! Local:
+
     INTEGER:: julian_day
     REAL:: julian_sec
+    INTEGER:: jd, m, y, d, ml
 
     !--------------------------------------------------------------------
 
-    CALL ymds2ju_internal(year, month, day, sec, julian_day, julian_sec)
+    lock_unan = .TRUE.
+
+    m = month
+    y = year
+    d = day
+
+    ! We deduce the calendar from the length of the year as it
+    ! is faster than an INDEX on the calendar variable.
+
+    ! Gregorian
+    IF ( (un_an > 365.0).AND.(un_an < 366.0) ) THEN
+       jd = (1461*(y+4800+INT(( m-14 )/12)))/4 &
+            &      +(367*(m-2-12*(INT(( m-14 )/12))))/12 &
+            &      -(3*((y+4900+INT((m-14)/12))/100))/4 &
+            &      +d-32075
+       jd = jd-2299160
+       ! No leap or All leap
+    ELSE IF (ABS(un_an-365.0) <= EPSILON(un_an) .OR. &
+         &   ABS(un_an-366.0) <= EPSILON(un_an)) THEN
+       ml = SUM(mon_len(1:m-1))
+       jd = y*INT(un_an)+ml+(d-1)
+       ! Calendar with regular month
+    ELSE
+       ml = INT(un_an)/12
+       jd = y*INT(un_an)+(m-1)*ml+(d-1)
+    ENDIF
+
+    julian_day = jd
+    julian_sec = sec
+
     julian = julian_day + julian_sec / un_jour
 
   END SUBROUTINE ymds2ju