FACT++  1.0
a2tf.c
Go to the documentation of this file.
1 #include "erfa.h"
2 
3 void eraA2tf(int ndp, double angle, char *sign, int ihmsf[4])
4 /*
5 ** - - - - - - - -
6 ** e r a A 2 t f
7 ** - - - - - - - -
8 **
9 ** Decompose radians into hours, minutes, seconds, fraction.
10 **
11 ** Given:
12 ** ndp int resolution (Note 1)
13 ** angle double angle in radians
14 **
15 ** Returned:
16 ** sign char '+' or '-'
17 ** ihmsf int[4] hours, minutes, seconds, fraction
18 **
19 ** Called:
20 ** eraD2tf decompose days to hms
21 **
22 ** Notes:
23 **
24 ** 1) The argument ndp is interpreted as follows:
25 **
26 ** ndp resolution
27 ** : ...0000 00 00
28 ** -7 1000 00 00
29 ** -6 100 00 00
30 ** -5 10 00 00
31 ** -4 1 00 00
32 ** -3 0 10 00
33 ** -2 0 01 00
34 ** -1 0 00 10
35 ** 0 0 00 01
36 ** 1 0 00 00.1
37 ** 2 0 00 00.01
38 ** 3 0 00 00.001
39 ** : 0 00 00.000...
40 **
41 ** 2) The largest positive useful value for ndp is determined by the
42 ** size of angle, the format of doubles on the target platform, and
43 ** the risk of overflowing ihmsf[3]. On a typical platform, for
44 ** angle up to 2pi, the available floating-point precision might
45 ** correspond to ndp=12. However, the practical limit is typically
46 ** ndp=9, set by the capacity of a 32-bit int, or ndp=4 if int is
47 ** only 16 bits.
48 **
49 ** 3) The absolute value of angle may exceed 2pi. In cases where it
50 ** does not, it is up to the caller to test for and handle the
51 ** case where angle is very nearly 2pi and rounds up to 24 hours,
52 ** by testing for ihmsf[0]=24 and setting ihmsf[0-3] to zero.
53 **
54 ** Copyright (C) 2013-2015, NumFOCUS Foundation.
55 ** Derived, with permission, from the SOFA library. See notes at end of file.
56 */
57 {
58 /* Scale then use days to h,m,s function. */
59  eraD2tf(ndp, angle/ERFA_D2PI, sign, ihmsf);
60 
61  return;
62 
63 }
64 /*----------------------------------------------------------------------
65 **
66 **
67 ** Copyright (C) 2013-2015, NumFOCUS Foundation.
68 ** All rights reserved.
69 **
70 ** This library is derived, with permission, from the International
71 ** Astronomical Union's "Standards of Fundamental Astronomy" library,
72 ** available from http://www.iausofa.org.
73 **
74 ** The ERFA version is intended to retain identical functionality to
75 ** the SOFA library, but made distinct through different function and
76 ** file names, as set out in the SOFA license conditions. The SOFA
77 ** original has a role as a reference standard for the IAU and IERS,
78 ** and consequently redistribution is permitted only in its unaltered
79 ** state. The ERFA version is not subject to this restriction and
80 ** therefore can be included in distributions which do not support the
81 ** concept of "read only" software.
82 **
83 ** Although the intent is to replicate the SOFA API (other than
84 ** replacement of prefix names) and results (with the exception of
85 ** bugs; any that are discovered will be fixed), SOFA is not
86 ** responsible for any errors found in this version of the library.
87 **
88 ** If you wish to acknowledge the SOFA heritage, please acknowledge
89 ** that you are using a library derived from SOFA, rather than SOFA
90 ** itself.
91 **
92 **
93 ** TERMS AND CONDITIONS
94 **
95 ** Redistribution and use in source and binary forms, with or without
96 ** modification, are permitted provided that the following conditions
97 ** are met:
98 **
99 ** 1 Redistributions of source code must retain the above copyright
100 ** notice, this list of conditions and the following disclaimer.
101 **
102 ** 2 Redistributions in binary form must reproduce the above copyright
103 ** notice, this list of conditions and the following disclaimer in
104 ** the documentation and/or other materials provided with the
105 ** distribution.
106 **
107 ** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
108 ** the International Astronomical Union nor the names of its
109 ** contributors may be used to endorse or promote products derived
110 ** from this software without specific prior written permission.
111 **
112 ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
113 ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
114 ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
115 ** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
116 ** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
117 ** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
118 ** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
119 ** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
120 ** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
121 ** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
122 ** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
123 ** POSSIBILITY OF SUCH DAMAGE.
124 **
125 */
ERFA_D2PI
#define ERFA_D2PI
Definition: erfam.h:48
eraA2tf
void eraA2tf(int ndp, double angle, char *sign, int ihmsf[4])
Definition: a2tf.c:3
eraD2tf
void eraD2tf(int ndp, double days, char *sign, int ihmsf[4])
Definition: d2tf.c:3