1 #include "sofa.h"
2
iauPnm00a(double date1,double date2,double rbpn[3][3])3 void iauPnm00a(double date1, double date2, double rbpn[3][3])
4 /*
5 ** - - - - - - - - - -
6 ** i a u P n m 0 0 a
7 ** - - - - - - - - - -
8 **
9 ** Form the matrix of precession-nutation for a given date (including
10 ** frame bias), equinox based, IAU 2000A model.
11 **
12 ** This function is part of the International Astronomical Union's
13 ** SOFA (Standards Of Fundamental Astronomy) software collection.
14 **
15 ** Status: support function.
16 **
17 ** Given:
18 ** date1,date2 double TT as a 2-part Julian Date (Note 1)
19 **
20 ** Returned:
21 ** rbpn double[3][3] bias-precession-nutation matrix (Note 2)
22 **
23 ** Notes:
24 **
25 ** 1) The TT date date1+date2 is a Julian Date, apportioned in any
26 ** convenient way between the two arguments. For example,
27 ** JD(TT)=2450123.7 could be expressed in any of these ways, among
28 ** others:
29 **
30 ** date1 date2
31 **
32 ** 2450123.7 0.0 (JD method)
33 ** 2451545.0 -1421.3 (J2000 method)
34 ** 2400000.5 50123.2 (MJD method)
35 ** 2450123.5 0.2 (date & time method)
36 **
37 ** The JD method is the most natural and convenient to use in
38 ** cases where the loss of several decimal digits of resolution
39 ** is acceptable. The J2000 method is best matched to the way
40 ** the argument is handled internally and will deliver the
41 ** optimum resolution. The MJD method and the date & time methods
42 ** are both good compromises between resolution and convenience.
43 **
44 ** 2) The matrix operates in the sense V(date) = rbpn * V(GCRS), where
45 ** the p-vector V(date) is with respect to the true equatorial triad
46 ** of date date1+date2 and the p-vector V(GCRS) is with respect to
47 ** the Geocentric Celestial Reference System (IAU, 2000).
48 **
49 ** 3) A faster, but slightly less accurate, result (about 1 mas) can be
50 ** obtained by using instead the iauPnm00b function.
51 **
52 ** Called:
53 ** iauPn00a bias/precession/nutation, IAU 2000A
54 **
55 ** Reference:
56 **
57 ** IAU: Trans. International Astronomical Union, Vol. XXIVB; Proc.
58 ** 24th General Assembly, Manchester, UK. Resolutions B1.3, B1.6.
59 ** (2000)
60 **
61 ** This revision: 2021 May 11
62 **
63 ** SOFA release 2021-05-12
64 **
65 ** Copyright (C) 2021 IAU SOFA Board. See notes at end.
66 */
67 {
68 double dpsi, deps, epsa, rb[3][3], rp[3][3], rbp[3][3], rn[3][3];
69
70
71 /* Obtain the required matrix (discarding other results). */
72 iauPn00a(date1, date2, &dpsi, &deps, &epsa, rb, rp, rbp, rn, rbpn);
73
74 /* Finished. */
75
76 /*----------------------------------------------------------------------
77 **
78 ** Copyright (C) 2021
79 ** Standards Of Fundamental Astronomy Board
80 ** of the International Astronomical Union.
81 **
82 ** =====================
83 ** SOFA Software License
84 ** =====================
85 **
86 ** NOTICE TO USER:
87 **
88 ** BY USING THIS SOFTWARE YOU ACCEPT THE FOLLOWING SIX TERMS AND
89 ** CONDITIONS WHICH APPLY TO ITS USE.
90 **
91 ** 1. The Software is owned by the IAU SOFA Board ("SOFA").
92 **
93 ** 2. Permission is granted to anyone to use the SOFA software for any
94 ** purpose, including commercial applications, free of charge and
95 ** without payment of royalties, subject to the conditions and
96 ** restrictions listed below.
97 **
98 ** 3. You (the user) may copy and distribute SOFA source code to others,
99 ** and use and adapt its code and algorithms in your own software,
100 ** on a world-wide, royalty-free basis. That portion of your
101 ** distribution that does not consist of intact and unchanged copies
102 ** of SOFA source code files is a "derived work" that must comply
103 ** with the following requirements:
104 **
105 ** a) Your work shall be marked or carry a statement that it
106 ** (i) uses routines and computations derived by you from
107 ** software provided by SOFA under license to you; and
108 ** (ii) does not itself constitute software provided by and/or
109 ** endorsed by SOFA.
110 **
111 ** b) The source code of your derived work must contain descriptions
112 ** of how the derived work is based upon, contains and/or differs
113 ** from the original SOFA software.
114 **
115 ** c) The names of all routines in your derived work shall not
116 ** include the prefix "iau" or "sofa" or trivial modifications
117 ** thereof such as changes of case.
118 **
119 ** d) The origin of the SOFA components of your derived work must
120 ** not be misrepresented; you must not claim that you wrote the
121 ** original software, nor file a patent application for SOFA
122 ** software or algorithms embedded in the SOFA software.
123 **
124 ** e) These requirements must be reproduced intact in any source
125 ** distribution and shall apply to anyone to whom you have
126 ** granted a further right to modify the source code of your
127 ** derived work.
128 **
129 ** Note that, as originally distributed, the SOFA software is
130 ** intended to be a definitive implementation of the IAU standards,
131 ** and consequently third-party modifications are discouraged. All
132 ** variations, no matter how minor, must be explicitly marked as
133 ** such, as explained above.
134 **
135 ** 4. You shall not cause the SOFA software to be brought into
136 ** disrepute, either by misuse, or use for inappropriate tasks, or
137 ** by inappropriate modification.
138 **
139 ** 5. The SOFA software is provided "as is" and SOFA makes no warranty
140 ** as to its use or performance. SOFA does not and cannot warrant
141 ** the performance or results which the user may obtain by using the
142 ** SOFA software. SOFA makes no warranties, express or implied, as
143 ** to non-infringement of third party rights, merchantability, or
144 ** fitness for any particular purpose. In no event will SOFA be
145 ** liable to the user for any consequential, incidental, or special
146 ** damages, including any lost profits or lost savings, even if a
147 ** SOFA representative has been advised of such damages, or for any
148 ** claim by any third party.
149 **
150 ** 6. The provision of any version of the SOFA software under the terms
151 ** and conditions specified herein does not imply that future
152 ** versions will also be made available under the same terms and
153 ** conditions.
154 *
155 ** In any published work or commercial product which uses the SOFA
156 ** software directly, acknowledgement (see www.iausofa.org) is
157 ** appreciated.
158 **
159 ** Correspondence concerning SOFA software should be addressed as
160 ** follows:
161 **
162 ** By email: sofa@ukho.gov.uk
163 ** By post: IAU SOFA Center
164 ** HM Nautical Almanac Office
165 ** UK Hydrographic Office
166 ** Admiralty Way, Taunton
167 ** Somerset, TA1 2DN
168 ** United Kingdom
169 **
170 **--------------------------------------------------------------------*/
171 }
172