source: trunk/FACT++/erfa/src/pnm80.c@ 18403

Last change on this file since 18403 was 18348, checked in by tbretz, 9 years ago
File size: 5.2 KB
Line 
1#include "erfa.h"
2
3void eraPnm80(double date1, double date2, double rmatpn[3][3])
4/*
5** - - - - - - - - -
6** e r a P n m 8 0
7** - - - - - - - - -
8**
9** Form the matrix of precession/nutation for a given date, IAU 1976
10** precession model, IAU 1980 nutation model.
11**
12** Given:
13** date1,date2 double TDB date (Note 1)
14**
15** Returned:
16** rmatpn double[3][3] combined precession/nutation matrix
17**
18** Notes:
19**
20** 1) The TDB date date1+date2 is a Julian Date, apportioned in any
21** convenient way between the two arguments. For example,
22** JD(TDB)=2450123.7 could be expressed in any of these ways,
23** among others:
24**
25** date1 date2
26**
27** 2450123.7 0.0 (JD method)
28** 2451545.0 -1421.3 (J2000 method)
29** 2400000.5 50123.2 (MJD method)
30** 2450123.5 0.2 (date & time method)
31**
32** The JD method is the most natural and convenient to use in
33** cases where the loss of several decimal digits of resolution
34** is acceptable. The J2000 method is best matched to the way
35** the argument is handled internally and will deliver the
36** optimum resolution. The MJD method and the date & time methods
37** are both good compromises between resolution and convenience.
38**
39** 2) The matrix operates in the sense V(date) = rmatpn * V(J2000),
40** where the p-vector V(date) is with respect to the true equatorial
41** triad of date date1+date2 and the p-vector V(J2000) is with
42** respect to the mean equatorial triad of epoch J2000.0.
43**
44** Called:
45** eraPmat76 precession matrix, IAU 1976
46** eraNutm80 nutation matrix, IAU 1980
47** eraRxr product of two r-matrices
48**
49** Reference:
50**
51** Explanatory Supplement to the Astronomical Almanac,
52** P. Kenneth Seidelmann (ed), University Science Books (1992),
53** Section 3.3 (p145).
54**
55** Copyright (C) 2013-2015, NumFOCUS Foundation.
56** Derived, with permission, from the SOFA library. See notes at end of file.
57*/
58{
59 double rmatp[3][3], rmatn[3][3];
60
61/* Precession matrix, J2000.0 to date. */
62 eraPmat76(date1, date2, rmatp);
63
64/* Nutation matrix. */
65 eraNutm80(date1, date2, rmatn);
66
67/* Combine the matrices: PN = N x P. */
68 eraRxr(rmatn, rmatp, rmatpn);
69
70 return;
71
72}
73/*----------------------------------------------------------------------
74**
75**
76** Copyright (C) 2013-2015, NumFOCUS Foundation.
77** All rights reserved.
78**
79** This library is derived, with permission, from the International
80** Astronomical Union's "Standards of Fundamental Astronomy" library,
81** available from http://www.iausofa.org.
82**
83** The ERFA version is intended to retain identical functionality to
84** the SOFA library, but made distinct through different function and
85** file names, as set out in the SOFA license conditions. The SOFA
86** original has a role as a reference standard for the IAU and IERS,
87** and consequently redistribution is permitted only in its unaltered
88** state. The ERFA version is not subject to this restriction and
89** therefore can be included in distributions which do not support the
90** concept of "read only" software.
91**
92** Although the intent is to replicate the SOFA API (other than
93** replacement of prefix names) and results (with the exception of
94** bugs; any that are discovered will be fixed), SOFA is not
95** responsible for any errors found in this version of the library.
96**
97** If you wish to acknowledge the SOFA heritage, please acknowledge
98** that you are using a library derived from SOFA, rather than SOFA
99** itself.
100**
101**
102** TERMS AND CONDITIONS
103**
104** Redistribution and use in source and binary forms, with or without
105** modification, are permitted provided that the following conditions
106** are met:
107**
108** 1 Redistributions of source code must retain the above copyright
109** notice, this list of conditions and the following disclaimer.
110**
111** 2 Redistributions in binary form must reproduce the above copyright
112** notice, this list of conditions and the following disclaimer in
113** the documentation and/or other materials provided with the
114** distribution.
115**
116** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
117** the International Astronomical Union nor the names of its
118** contributors may be used to endorse or promote products derived
119** from this software without specific prior written permission.
120**
121** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
122** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
123** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
124** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
125** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
126** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
127** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
128** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
129** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
130** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
131** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
132** POSSIBILITY OF SUCH DAMAGE.
133**
134*/
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