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84 lines
2.1 KiB
Fortran
84 lines
2.1 KiB
Fortran
SUBROUTINE sla_DJCL (DJM, IY, IM, ID, FD, J)
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*+
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* - - - - -
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* D J C L
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* - - - - -
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*
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* Modified Julian Date to Gregorian year, month, day,
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* and fraction of a day.
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*
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* Given:
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* DJM dp modified Julian Date (JD-2400000.5)
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*
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* Returned:
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* IY int year
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* IM int month
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* ID int day
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* FD dp fraction of day
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* J int status:
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* 0 = OK
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* -1 = unacceptable date (before 4701BC March 1)
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*
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* The algorithm is adapted from Hatcher 1984 (QJRAS 25, 53-55).
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*
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* Last revision: 22 July 2004
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*
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* Copyright P.T.Wallace. All rights reserved.
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*
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* License:
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program (see SLA_CONDITIONS); if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place, Suite 330,
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* Boston, MA 02111-1307 USA
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*
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*-
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IMPLICIT NONE
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DOUBLE PRECISION DJM
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INTEGER IY,IM,ID
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DOUBLE PRECISION FD
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INTEGER J
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DOUBLE PRECISION F,D
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INTEGER JD,N4,ND10
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* Check if date is acceptable.
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IF ( DJM.LE.-2395520D0 .OR. DJM.GE.1D9 ) THEN
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J = -1
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ELSE
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J = 0
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* Separate day and fraction.
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F = MOD(DJM,1D0)
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IF (F.LT.0D0) F = F+1D0
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D = ANINT(DJM-F)
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* Express day in Gregorian calendar.
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JD = NINT(D)+2400001
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N4 = 4*(JD+((6*((4*JD-17918)/146097))/4+1)/2-37)
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ND10 = 10*(MOD(N4-237,1461)/4)+5
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IY = N4/1461-4712
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IM = MOD(ND10/306+2,12)+1
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ID = MOD(ND10,306)/10+1
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FD = F
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J=0
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END IF
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END
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