source: branches/FACT++_part_filenames/erfa/src/numat.c@ 20051

Last change on this file since 20051 was 18711, checked in by tbretz, 8 years ago
Updated to ERFA 1.3.0 (no relevant code change except the leap second at the beginning of 2017)
File size: 4.5 KB
Line 
1#include "erfa.h"
2
3void eraNumat(double epsa, double dpsi, double deps, double rmatn[3][3])
4/*
5** - - - - - - - - -
6** e r a N u m a t
7** - - - - - - - - -
8**
9** Form the matrix of nutation.
10**
11** Given:
12** epsa double mean obliquity of date (Note 1)
13** dpsi,deps double nutation (Note 2)
14**
15** Returned:
16** rmatn double[3][3] nutation matrix (Note 3)
17**
18** Notes:
19**
20**
21** 1) The supplied mean obliquity epsa, must be consistent with the
22** precession-nutation models from which dpsi and deps were obtained.
23**
24** 2) The caller is responsible for providing the nutation components;
25** they are in longitude and obliquity, in radians and are with
26** respect to the equinox and ecliptic of date.
27**
28** 3) The matrix operates in the sense V(true) = rmatn * V(mean),
29** where the p-vector V(true) is with respect to the true
30** equatorial triad of date and the p-vector V(mean) is with
31** respect to the mean equatorial triad of date.
32**
33** Called:
34** eraIr initialize r-matrix to identity
35** eraRx rotate around X-axis
36** eraRz rotate around Z-axis
37**
38** Reference:
39**
40** Explanatory Supplement to the Astronomical Almanac,
41** P. Kenneth Seidelmann (ed), University Science Books (1992),
42** Section 3.222-3 (p114).
43**
44** Copyright (C) 2013-2016, NumFOCUS Foundation.
45** Derived, with permission, from the SOFA library. See notes at end of file.
46*/
47{
48/* Build the rotation matrix. */
49 eraIr(rmatn);
50 eraRx(epsa, rmatn);
51 eraRz(-dpsi, rmatn);
52 eraRx(-(epsa + deps), rmatn);
53
54 return;
55
56}
57/*----------------------------------------------------------------------
58**
59**
60** Copyright (C) 2013-2016, NumFOCUS Foundation.
61** All rights reserved.
62**
63** This library is derived, with permission, from the International
64** Astronomical Union's "Standards of Fundamental Astronomy" library,
65** available from http://www.iausofa.org.
66**
67** The ERFA version is intended to retain identical functionality to
68** the SOFA library, but made distinct through different function and
69** file names, as set out in the SOFA license conditions. The SOFA
70** original has a role as a reference standard for the IAU and IERS,
71** and consequently redistribution is permitted only in its unaltered
72** state. The ERFA version is not subject to this restriction and
73** therefore can be included in distributions which do not support the
74** concept of "read only" software.
75**
76** Although the intent is to replicate the SOFA API (other than
77** replacement of prefix names) and results (with the exception of
78** bugs; any that are discovered will be fixed), SOFA is not
79** responsible for any errors found in this version of the library.
80**
81** If you wish to acknowledge the SOFA heritage, please acknowledge
82** that you are using a library derived from SOFA, rather than SOFA
83** itself.
84**
85**
86** TERMS AND CONDITIONS
87**
88** Redistribution and use in source and binary forms, with or without
89** modification, are permitted provided that the following conditions
90** are met:
91**
92** 1 Redistributions of source code must retain the above copyright
93** notice, this list of conditions and the following disclaimer.
94**
95** 2 Redistributions in binary form must reproduce the above copyright
96** notice, this list of conditions and the following disclaimer in
97** the documentation and/or other materials provided with the
98** distribution.
99**
100** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
101** the International Astronomical Union nor the names of its
102** contributors may be used to endorse or promote products derived
103** from this software without specific prior written permission.
104**
105** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
106** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
107** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
108** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
109** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
110** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
111** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
112** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
113** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
114** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
115** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
116** POSSIBILITY OF SUCH DAMAGE.
117**
118*/
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