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authorJoe Hunkeler <jhunkeler@gmail.com>2015-08-11 16:51:37 -0400
committerJoe Hunkeler <jhunkeler@gmail.com>2015-08-11 16:51:37 -0400
commit40e5a5811c6ffce9b0974e93cdd927cbcf60c157 (patch)
tree4464880c571602d54f6ae114729bf62a89518057 /math/slalib/dd2tf.f
downloadiraf-osx-40e5a5811c6ffce9b0974e93cdd927cbcf60c157.tar.gz
Repatch (from linux) of OSX IRAF
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+ SUBROUTINE slDDTF (NDP, DAYS, SIGN, IHMSF)
+*+
+* - - - - - -
+* D D T F
+* - - - - - -
+*
+* Convert an interval in days into hours, minutes, seconds
+* (double precision)
+*
+* Given:
+* NDP i number of decimal places of seconds
+* DAYS d interval in days
+*
+* Returned:
+* SIGN c '+' or '-'
+* IHMSF i(4) hours, minutes, seconds, fraction
+*
+* Notes:
+*
+* 1) NDP less than zero is interpreted as zero.
+*
+* 2) The largest useful value for NDP is determined by the size
+* of DAYS, the format of DOUBLE PRECISION floating-point numbers
+* on the target machine, and the risk of overflowing IHMSF(4).
+* On some architectures, for DAYS up to 1D0, the available
+* floating-point precision corresponds roughly to NDP=12.
+* However, the practical limit is NDP=9, set by the capacity of
+* a typical 32-bit IHMSF(4).
+*
+* 3) The absolute value of DAYS may exceed 1D0. In cases where it
+* does not, it is up to the caller to test for and handle the
+* case where DAYS is very nearly 1D0 and rounds up to 24 hours,
+* by testing for IHMSF(1)=24 and setting IHMSF(1-4) to zero.
+*
+* Last revision: 26 December 2004
+*
+* Copyright P.T.Wallace. All rights reserved.
+*
+* License:
+* This program is free software; you can redistribute it and/or modify
+* it under the terms of the GNU General Public License as published by
+* the Free Software Foundation; either version 2 of the License, or
+* (at your option) any later version.
+*
+* This program is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with this program (see SLA_CONDITIONS); if not, write to the
+* Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+* Boston, MA 02110-1301 USA
+*
+* Copyright (C) 1995 Association of Universities for Research in Astronomy Inc.
+*-
+
+ IMPLICIT NONE
+
+ INTEGER NDP
+ DOUBLE PRECISION DAYS
+ CHARACTER SIGN*(*)
+ INTEGER IHMSF(4)
+
+* Days to seconds
+ DOUBLE PRECISION D2S
+ PARAMETER (D2S=86400D0)
+
+ INTEGER NRS,N
+ DOUBLE PRECISION RS,RM,RH,A,AH,AM,AS,AF
+
+
+
+* Handle sign
+ IF (DAYS.GE.0D0) THEN
+ SIGN='+'
+ ELSE
+ SIGN='-'
+ END IF
+
+* Field units in terms of least significant figure
+ NRS=1
+ DO N=1,NDP
+ NRS=NRS*10
+ END DO
+ RS=DBLE(NRS)
+ RM=RS*60D0
+ RH=RM*60D0
+
+* Round interval and express in smallest units required
+ A=ANINT(RS*D2S*ABS(DAYS))
+
+* Separate into fields
+ AH=AINT(A/RH)
+ A=A-AH*RH
+ AM=AINT(A/RM)
+ A=A-AM*RM
+ AS=AINT(A/RS)
+ AF=A-AS*RS
+
+* Return results
+ IHMSF(1)=MAX(NINT(AH),0)
+ IHMSF(2)=MAX(MIN(NINT(AM),59),0)
+ IHMSF(3)=MAX(MIN(NINT(AS),59),0)
+ IHMSF(4)=MAX(NINT(MIN(AF,RS-1D0)),0)
+
+ END