source: trunk/FACT++/sofa/src/a2tf.c@ 18365

Last change on this file since 18365 was 18346, checked in by tbretz, 10 years ago
File size: 6.2 KB
Line 
1#include "sofa.h"
2
3void iauA2tf(int ndp, double angle, char *sign, int ihmsf[4])
4/*
5** - - - - - - - -
6** i a u A 2 t f
7** - - - - - - - -
8**
9** Decompose radians into hours, minutes, seconds, fraction.
10**
11** This function is part of the International Astronomical Union's
12** SOFA (Standards Of Fundamental Astronomy) software collection.
13**
14** Status: vector/matrix support function.
15**
16** Given:
17** ndp int resolution (Note 1)
18** angle double angle in radians
19**
20** Returned:
21** sign char '+' or '-'
22** ihmsf int[4] hours, minutes, seconds, fraction
23**
24** Called:
25** iauD2tf decompose days to hms
26**
27** Notes:
28**
29** 1) The argument ndp is interpreted as follows:
30**
31** ndp resolution
32** : ...0000 00 00
33** -7 1000 00 00
34** -6 100 00 00
35** -5 10 00 00
36** -4 1 00 00
37** -3 0 10 00
38** -2 0 01 00
39** -1 0 00 10
40** 0 0 00 01
41** 1 0 00 00.1
42** 2 0 00 00.01
43** 3 0 00 00.001
44** : 0 00 00.000...
45**
46** 2) The largest positive useful value for ndp is determined by the
47** size of angle, the format of doubles on the target platform, and
48** the risk of overflowing ihmsf[3]. On a typical platform, for
49** angle up to 2pi, the available floating-point precision might
50** correspond to ndp=12. However, the practical limit is typically
51** ndp=9, set by the capacity of a 32-bit int, or ndp=4 if int is
52** only 16 bits.
53**
54** 3) The absolute value of angle may exceed 2pi. In cases where it
55** does not, it is up to the caller to test for and handle the
56** case where angle is very nearly 2pi and rounds up to 24 hours,
57** by testing for ihmsf[0]=24 and setting ihmsf[0-3] to zero.
58**
59** This revision: 2013 July 31
60**
61** SOFA release 2015-02-09
62**
63** Copyright (C) 2015 IAU SOFA Board. See notes at end.
64*/
65{
66/* Scale then use days to h,m,s function. */
67 iauD2tf(ndp, angle/D2PI, sign, ihmsf);
68
69 return;
70
71/*----------------------------------------------------------------------
72**
73** Copyright (C) 2015
74** Standards Of Fundamental Astronomy Board
75** of the International Astronomical Union.
76**
77** =====================
78** SOFA Software License
79** =====================
80**
81** NOTICE TO USER:
82**
83** BY USING THIS SOFTWARE YOU ACCEPT THE FOLLOWING SIX TERMS AND
84** CONDITIONS WHICH APPLY TO ITS USE.
85**
86** 1. The Software is owned by the IAU SOFA Board ("SOFA").
87**
88** 2. Permission is granted to anyone to use the SOFA software for any
89** purpose, including commercial applications, free of charge and
90** without payment of royalties, subject to the conditions and
91** restrictions listed below.
92**
93** 3. You (the user) may copy and distribute SOFA source code to others,
94** and use and adapt its code and algorithms in your own software,
95** on a world-wide, royalty-free basis. That portion of your
96** distribution that does not consist of intact and unchanged copies
97** of SOFA source code files is a "derived work" that must comply
98** with the following requirements:
99**
100** a) Your work shall be marked or carry a statement that it
101** (i) uses routines and computations derived by you from
102** software provided by SOFA under license to you; and
103** (ii) does not itself constitute software provided by and/or
104** endorsed by SOFA.
105**
106** b) The source code of your derived work must contain descriptions
107** of how the derived work is based upon, contains and/or differs
108** from the original SOFA software.
109**
110** c) The names of all routines in your derived work shall not
111** include the prefix "iau" or "sofa" or trivial modifications
112** thereof such as changes of case.
113**
114** d) The origin of the SOFA components of your derived work must
115** not be misrepresented; you must not claim that you wrote the
116** original software, nor file a patent application for SOFA
117** software or algorithms embedded in the SOFA software.
118**
119** e) These requirements must be reproduced intact in any source
120** distribution and shall apply to anyone to whom you have
121** granted a further right to modify the source code of your
122** derived work.
123**
124** Note that, as originally distributed, the SOFA software is
125** intended to be a definitive implementation of the IAU standards,
126** and consequently third-party modifications are discouraged. All
127** variations, no matter how minor, must be explicitly marked as
128** such, as explained above.
129**
130** 4. You shall not cause the SOFA software to be brought into
131** disrepute, either by misuse, or use for inappropriate tasks, or
132** by inappropriate modification.
133**
134** 5. The SOFA software is provided "as is" and SOFA makes no warranty
135** as to its use or performance. SOFA does not and cannot warrant
136** the performance or results which the user may obtain by using the
137** SOFA software. SOFA makes no warranties, express or implied, as
138** to non-infringement of third party rights, merchantability, or
139** fitness for any particular purpose. In no event will SOFA be
140** liable to the user for any consequential, incidental, or special
141** damages, including any lost profits or lost savings, even if a
142** SOFA representative has been advised of such damages, or for any
143** claim by any third party.
144**
145** 6. The provision of any version of the SOFA software under the terms
146** and conditions specified herein does not imply that future
147** versions will also be made available under the same terms and
148** conditions.
149*
150** In any published work or commercial product which uses the SOFA
151** software directly, acknowledgement (see www.iausofa.org) is
152** appreciated.
153**
154** Correspondence concerning SOFA software should be addressed as
155** follows:
156**
157** By email: sofa@ukho.gov.uk
158** By post: IAU SOFA Center
159** HM Nautical Almanac Office
160** UK Hydrographic Office
161** Admiralty Way, Taunton
162** Somerset, TA1 2DN
163** United Kingdom
164**
165**--------------------------------------------------------------------*/
166}
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