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