FACT++  1.0
numat.c
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1 #include "erfa.h"
2 
3 void eraNumat(double epsa, double dpsi, double deps, double rmatn[3][3])
4 /*
5 ** - - - - - - - - -
6 ** e r a N u m a t
7 ** - - - - - - - - -
8 **
9 ** Form the matrix of nutation.
10 **
11 ** Given:
12 ** epsa double mean obliquity of date (Note 1)
13 ** dpsi,deps double nutation (Note 2)
14 **
15 ** Returned:
16 ** rmatn double[3][3] nutation matrix (Note 3)
17 **
18 ** Notes:
19 **
20 ** 1) The supplied mean obliquity epsa, must be consistent with the
21 ** precession-nutation models from which dpsi and deps were obtained.
22 **
23 ** 2) The caller is responsible for providing the nutation components;
24 ** they are in longitude and obliquity, in radians and are with
25 ** respect to the equinox and ecliptic of date.
26 **
27 ** 3) The matrix operates in the sense V(true) = rmatn * V(mean),
28 ** where the p-vector V(true) is with respect to the true
29 ** equatorial triad of date and the p-vector V(mean) is with
30 ** respect to the mean equatorial triad of date.
31 **
32 ** Called:
33 ** eraIr initialize r-matrix to identity
34 ** eraRx rotate around X-axis
35 ** eraRz rotate around Z-axis
36 **
37 ** Reference:
38 **
39 ** Explanatory Supplement to the Astronomical Almanac,
40 ** P. Kenneth Seidelmann (ed), University Science Books (1992),
41 ** Section 3.222-3 (p114).
42 **
43 ** Copyright (C) 2013-2015, NumFOCUS Foundation.
44 ** Derived, with permission, from the SOFA library. See notes at end of file.
45 */
46 {
47 /* Build the rotation matrix. */
48  eraIr(rmatn);
49  eraRx(epsa, rmatn);
50  eraRz(-dpsi, rmatn);
51  eraRx(-(epsa + deps), rmatn);
52 
53  return;
54 
55 }
56 /*----------------------------------------------------------------------
57 **
58 **
59 ** Copyright (C) 2013-2015, NumFOCUS Foundation.
60 ** All rights reserved.
61 **
62 ** This library is derived, with permission, from the International
63 ** Astronomical Union's "Standards of Fundamental Astronomy" library,
64 ** available from http://www.iausofa.org.
65 **
66 ** The ERFA version is intended to retain identical functionality to
67 ** the SOFA library, but made distinct through different function and
68 ** file names, as set out in the SOFA license conditions. The SOFA
69 ** original has a role as a reference standard for the IAU and IERS,
70 ** and consequently redistribution is permitted only in its unaltered
71 ** state. The ERFA version is not subject to this restriction and
72 ** therefore can be included in distributions which do not support the
73 ** concept of "read only" software.
74 **
75 ** Although the intent is to replicate the SOFA API (other than
76 ** replacement of prefix names) and results (with the exception of
77 ** bugs; any that are discovered will be fixed), SOFA is not
78 ** responsible for any errors found in this version of the library.
79 **
80 ** If you wish to acknowledge the SOFA heritage, please acknowledge
81 ** that you are using a library derived from SOFA, rather than SOFA
82 ** itself.
83 **
84 **
85 ** TERMS AND CONDITIONS
86 **
87 ** Redistribution and use in source and binary forms, with or without
88 ** modification, are permitted provided that the following conditions
89 ** are met:
90 **
91 ** 1 Redistributions of source code must retain the above copyright
92 ** notice, this list of conditions and the following disclaimer.
93 **
94 ** 2 Redistributions in binary form must reproduce the above copyright
95 ** notice, this list of conditions and the following disclaimer in
96 ** the documentation and/or other materials provided with the
97 ** distribution.
98 **
99 ** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
100 ** the International Astronomical Union nor the names of its
101 ** contributors may be used to endorse or promote products derived
102 ** from this software without specific prior written permission.
103 **
104 ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
105 ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
106 ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
107 ** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
108 ** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
109 ** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
110 ** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
111 ** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
112 ** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
113 ** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
114 ** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
115 ** POSSIBILITY OF SUCH DAMAGE.
116 **
117 */
eraRx
void eraRx(double phi, double r[3][3])
Definition: rx.c:3
eraIr
void eraIr(double r[3][3])
Definition: ir.c:3
eraRz
void eraRz(double psi, double r[3][3])
Definition: rz.c:3
eraNumat
void eraNumat(double epsa, double dpsi, double deps, double rmatn[3][3])
Definition: numat.c:3