SLA_CLYD - Calendar to Year, Day

ACTION:

Gregorian calendar date to year and day in year, in a Julian calendar aligned to the 20th/21st century Gregorian calendar.

CALL:

CALL sla_CLYD (IY, IM, ID, NY, ND, J)

GIVEN:

IY,IM,ID

I

year, month, day in Gregorian calendar

RETURNED:

NY	I	year (re-aligned Julian calendar)
ND	I	day in year (1 = January 1st)
J	I	status:
		0 = OK
		1 = bad year (before $-4711$)
		2 = bad month
		3 = bad day

NOTES:

1. The purpose of sla_CLYD is to support sla_EARTH, sla_MOON and sla_ECOR.
2. Between 1900 March 1 and 2100 February 28 it returns answers which are consistent with the ordinary Gregorian calendar. Outside this range there will be a discrepancy which increases by one day for every non-leap century year.
3. When an invalid year or month is supplied (status J = 1 or J = 2) the results are not computed. When a day is supplied which is outside the conventional range (status J = 3) the results are computed.