From d54fe7c1f704a63824c5bfa0ece65245572e9b27 Mon Sep 17 00:00:00 2001 From: Joseph Hunkeler Date: Wed, 4 Mar 2015 21:21:30 -0500 Subject: Initial commit --- src/slalib/calyd.f | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) create mode 100644 src/slalib/calyd.f (limited to 'src/slalib/calyd.f') diff --git a/src/slalib/calyd.f b/src/slalib/calyd.f new file mode 100644 index 0000000..240a887 --- /dev/null +++ b/src/slalib/calyd.f @@ -0,0 +1,65 @@ + SUBROUTINE sla_CALYD (IY, IM, ID, NY, ND, J) +*+ +* - - - - - - +* C A L Y D +* - - - - - - +* +* Gregorian calendar date to year and day in year (in a Julian +* calendar aligned to the 20th/21st century Gregorian calendar). +* +* (Includes century default feature: use sla_CLYD for years +* before 100AD.) +* +* Given: +* IY,IM,ID int year, month, day in Gregorian calendar +* (year may optionally omit the century) +* Returned: +* NY int year (re-aligned Julian calendar) +* ND int day in year (1 = January 1st) +* J int status: +* 0 = OK +* 1 = bad year (before -4711) +* 2 = bad month +* 3 = bad day (but conversion performed) +* +* Notes: +* +* 1 This routine exists to support the low-precision routines +* 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 Years in the range 50-99 are interpreted as 1950-1999, and +* years in the range 00-49 are interpreted as 2000-2049. +* +* Called: sla_CLYD +* +* P.T.Wallace Starlink 23 November 1994 +* +* Copyright (C) 1995 Rutherford Appleton Laboratory +*- + + IMPLICIT NONE + + INTEGER IY,IM,ID,NY,ND,J + + INTEGER I + + + +* Default century if appropriate + IF (IY.GE.0.AND.IY.LE.49) THEN + I=IY+2000 + ELSE IF (IY.GE.50.AND.IY.LE.99) THEN + I=IY+1900 + ELSE + I=IY + END IF + +* Perform the conversion + CALL sla_CLYD(I,IM,ID,NY,ND,J) + + END -- cgit