aboutsummaryrefslogtreecommitdiff
path: root/math/slalib/cr2tf.f
blob: b23cbd2edae21c2011a3de813a47d3bdb3a0ef4b (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
SUBROUTINE slCRTF (NDP, ANGLE, SIGN, IHMSF)
*+
*     - - - - - -
*      C R T F
*     - - - - - -
*
*  Convert an angle in radians into hours, minutes, seconds
*  (single precision)
*
*  Given:
*     NDP       int      number of decimal places of seconds
*     ANGLE     real     angle in radians
*
*  Returned:
*     SIGN      char     '+' or '-'
*     IHMSF     int(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
*      ANGLE, the format of REAL floating-point numbers on the target
*      machine, and the risk of overflowing IHMSF(4).  On some
*      architectures, for ANGLE up to 2pi, the available floating-point
*      precision corresponds roughly to NDP=3.  This is well below
*      the ultimate limit of NDP=9 set by the capacity of a typical
*      32-bit IHMSF(4).
*
*  3)  The absolute value of ANGLE may exceed 2pi.  In cases where it
*      does not, it is up to the caller to test for and handle the
*      case where ANGLE is very nearly 2pi and rounds up to 24 hours,
*      by testing for IHMSF(1)=24 and setting IHMSF(1-4) to zero.
*
*  Called:  slCDTF
*
*  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
      REAL ANGLE
      CHARACTER SIGN*(*)
      INTEGER IHMSF(4)

*  Turns to radians
      REAL T2R
      PARAMETER (T2R=6.283185307179586476925287)



*  Scale then use days to h,m,s routine
      CALL slCDTF(NDP,ANGLE/T2R,SIGN,IHMSF)

      END