source: trunk/FACT++/erfa/src/num00a.c

Last change on this file was 18921, checked in by tbretz, 7 years ago
Updated to ERFA 1.4.0
File size: 5.1 KB
Line 
1#include "erfa.h"
2
3void eraNum00a(double date1, double date2, double rmatn[3][3])
4/*
5** - - - - - - - - - -
6** e r a N u m 0 0 a
7** - - - - - - - - - -
8**
9** Form the matrix of nutation for a given date, IAU 2000A model.
10**
11** Given:
12** date1,date2 double TT as a 2-part Julian Date (Note 1)
13**
14** Returned:
15** rmatn double[3][3] nutation matrix
16**
17** Notes:
18**
19** 1) The TT date date1+date2 is a Julian Date, apportioned in any
20** convenient way between the two arguments. For example,
21** JD(TT)=2450123.7 could be expressed in any of these ways,
22** among others:
23**
24** date1 date2
25**
26** 2450123.7 0.0 (JD method)
27** 2451545.0 -1421.3 (J2000 method)
28** 2400000.5 50123.2 (MJD method)
29** 2450123.5 0.2 (date & time method)
30**
31** The JD method is the most natural and convenient to use in
32** cases where the loss of several decimal digits of resolution
33** is acceptable. The J2000 method is best matched to the way
34** the argument is handled internally and will deliver the
35** optimum resolution. The MJD method and the date & time methods
36** are both good compromises between resolution and convenience.
37**
38** 2) The matrix operates in the sense V(true) = rmatn * V(mean), where
39** the p-vector V(true) is with respect to the true equatorial triad
40** of date and the p-vector V(mean) is with respect to the mean
41** equatorial triad of date.
42**
43** 3) A faster, but slightly less accurate result (about 1 mas), can be
44** obtained by using instead the eraNum00b function.
45**
46** Called:
47** eraPn00a bias/precession/nutation, IAU 2000A
48**
49** Reference:
50**
51** Explanatory Supplement to the Astronomical Almanac,
52** P. Kenneth Seidelmann (ed), University Science Books (1992),
53** Section 3.222-3 (p114).
54**
55** Copyright (C) 2013-2017, NumFOCUS Foundation.
56** Derived, with permission, from the SOFA library. See notes at end of file.
57*/
58{
59 double dpsi, deps, epsa, rb[3][3], rp[3][3], rbp[3][3], rbpn[3][3];
60
61
62/* Obtain the required matrix (discarding other results). */
63 eraPn00a(date1, date2,
64 &dpsi, &deps, &epsa, rb, rp, rbp, rmatn, rbpn);
65
66 return;
67
68}
69/*----------------------------------------------------------------------
70**
71**
72** Copyright (C) 2013-2017, NumFOCUS Foundation.
73** All rights reserved.
74**
75** This library is derived, with permission, from the International
76** Astronomical Union's "Standards of Fundamental Astronomy" library,
77** available from http://www.iausofa.org.
78**
79** The ERFA version is intended to retain identical functionality to
80** the SOFA library, but made distinct through different function and
81** file names, as set out in the SOFA license conditions. The SOFA
82** original has a role as a reference standard for the IAU and IERS,
83** and consequently redistribution is permitted only in its unaltered
84** state. The ERFA version is not subject to this restriction and
85** therefore can be included in distributions which do not support the
86** concept of "read only" software.
87**
88** Although the intent is to replicate the SOFA API (other than
89** replacement of prefix names) and results (with the exception of
90** bugs; any that are discovered will be fixed), SOFA is not
91** responsible for any errors found in this version of the library.
92**
93** If you wish to acknowledge the SOFA heritage, please acknowledge
94** that you are using a library derived from SOFA, rather than SOFA
95** itself.
96**
97**
98** TERMS AND CONDITIONS
99**
100** Redistribution and use in source and binary forms, with or without
101** modification, are permitted provided that the following conditions
102** are met:
103**
104** 1 Redistributions of source code must retain the above copyright
105** notice, this list of conditions and the following disclaimer.
106**
107** 2 Redistributions in binary form must reproduce the above copyright
108** notice, this list of conditions and the following disclaimer in
109** the documentation and/or other materials provided with the
110** distribution.
111**
112** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
113** the International Astronomical Union nor the names of its
114** contributors may be used to endorse or promote products derived
115** from this software without specific prior written permission.
116**
117** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
118** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
119** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
120** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
121** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
122** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
123** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
124** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
125** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
126** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
127** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
128** POSSIBILITY OF SUCH DAMAGE.
129**
130*/
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