1 #include "erfa.h"
2 
eraPnm80(double date1,double date2,double rmatpn[3][3])3 void 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) 2013-2014, 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 
62 /* Precession matrix, J2000.0 to date. */
63    eraPmat76(date1, date2, rmatp);
64 
65 /* Nutation matrix. */
66    eraNutm80(date1, date2, rmatn);
67 
68 /* Combine the matrices:  PN = N x P. */
69    eraRxr(rmatn, rmatp, rmatpn);
70 
71    return;
72 
73 }
74 /*----------------------------------------------------------------------
75 **
76 **
77 **  Copyright (C) 2013-2014, NumFOCUS Foundation.
78 **  All rights reserved.
79 **
80 **  This library is derived, with permission, from the International
81 **  Astronomical Union's "Standards of Fundamental Astronomy" library,
82 **  available from http://www.iausofa.org.
83 **
84 **  The ERFA version is intended to retain identical functionality to
85 **  the SOFA library, but made distinct through different function and
86 **  file names, as set out in the SOFA license conditions.  The SOFA
87 **  original has a role as a reference standard for the IAU and IERS,
88 **  and consequently redistribution is permitted only in its unaltered
89 **  state.  The ERFA version is not subject to this restriction and
90 **  therefore can be included in distributions which do not support the
91 **  concept of "read only" software.
92 **
93 **  Although the intent is to replicate the SOFA API (other than
94 **  replacement of prefix names) and results (with the exception of
95 **  bugs;  any that are discovered will be fixed), SOFA is not
96 **  responsible for any errors found in this version of the library.
97 **
98 **  If you wish to acknowledge the SOFA heritage, please acknowledge
99 **  that you are using a library derived from SOFA, rather than SOFA
100 **  itself.
101 **
102 **
103 **  TERMS AND CONDITIONS
104 **
105 **  Redistribution and use in source and binary forms, with or without
106 **  modification, are permitted provided that the following conditions
107 **  are met:
108 **
109 **  1 Redistributions of source code must retain the above copyright
110 **    notice, this list of conditions and the following disclaimer.
111 **
112 **  2 Redistributions in binary form must reproduce the above copyright
113 **    notice, this list of conditions and the following disclaimer in
114 **    the documentation and/or other materials provided with the
115 **    distribution.
116 **
117 **  3 Neither the name of the Standards Of Fundamental Astronomy Board,
118 **    the International Astronomical Union nor the names of its
119 **    contributors may be used to endorse or promote products derived
120 **    from this software without specific prior written permission.
121 **
122 **  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
123 **  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
124 **  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
125 **  FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
126 **  COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
127 **  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
128 **  BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
129 **  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
130 **  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
131 **  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
132 **  ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
133 **  POSSIBILITY OF SUCH DAMAGE.
134 **
135 */
136