File Coverage

erfasrc/src/pmat76.c
Criterion Covered Total %
statement 0 8 0.0
branch n/a
condition n/a
subroutine n/a
pod n/a
total 0 8 0.0


line stmt bran cond sub pod time code
1             #include "erfa.h"
2              
3 0           void eraPmat76(double date1, double date2, double rmatp[3][3])
4             /*
5             ** - - - - - - - - - -
6             ** e r a P m a t 7 6
7             ** - - - - - - - - - -
8             **
9             ** Precession matrix from J2000.0 to a specified date, IAU 1976 model.
10             **
11             ** Given:
12             ** date1,date2 double ending date, TT (Note 1)
13             **
14             ** Returned:
15             ** rmatp double[3][3] precession matrix, J2000.0 -> date1+date2
16             **
17             ** Notes:
18             **
19             ** 1) The TT date date1+date2 is a Julian Date, apportioned in any
20             ** convenient way between the two arguments. For example,
21             ** JD(TT)=2450123.7 could be expressed in any of these ways,
22             ** among others:
23             **
24             ** date1 date2
25             **
26             ** 2450123.7 0.0 (JD method)
27             ** 2451545.0 -1421.3 (J2000 method)
28             ** 2400000.5 50123.2 (MJD method)
29             ** 2450123.5 0.2 (date & time method)
30             **
31             ** The JD method is the most natural and convenient to use in
32             ** cases where the loss of several decimal digits of resolution
33             ** is acceptable. The J2000 method is best matched to the way
34             ** the argument is handled internally and will deliver the
35             ** optimum resolution. The MJD method and the date & time methods
36             ** are both good compromises between resolution and convenience.
37             **
38             ** 2) The matrix operates in the sense V(date) = RMATP * V(J2000),
39             ** where the p-vector V(J2000) is with respect to the mean
40             ** equatorial triad of epoch J2000.0 and the p-vector V(date)
41             ** is with respect to the mean equatorial triad of the given
42             ** date.
43             **
44             ** 3) Though the matrix method itself is rigorous, the precession
45             ** angles are expressed through canonical polynomials which are
46             ** valid only for a limited time span. In addition, the IAU 1976
47             ** precession rate is known to be imperfect. The absolute accuracy
48             ** of the present formulation is better than 0.1 arcsec from
49             ** 1960AD to 2040AD, better than 1 arcsec from 1640AD to 2360AD,
50             ** and remains below 3 arcsec for the whole of the period
51             ** 500BC to 3000AD. The errors exceed 10 arcsec outside the
52             ** range 1200BC to 3900AD, exceed 100 arcsec outside 4200BC to
53             ** 5600AD and exceed 1000 arcsec outside 6800BC to 8200AD.
54             **
55             ** Called:
56             ** eraPrec76 accumulated precession angles, IAU 1976
57             ** eraIr initialize r-matrix to identity
58             ** eraRz rotate around Z-axis
59             ** eraRy rotate around Y-axis
60             ** eraCr copy r-matrix
61             **
62             ** References:
63             **
64             ** Lieske, J.H., 1979, Astron.Astrophys. 73, 282.
65             ** equations (6) & (7), p283.
66             **
67             ** Kaplan,G.H., 1981. USNO circular no. 163, pA2.
68             **
69             ** Copyright (C) 2013-2019, NumFOCUS Foundation.
70             ** Derived, with permission, from the SOFA library. See notes at end of file.
71             */
72             {
73             double zeta, z, theta, wmat[3][3];
74              
75              
76             /* Precession Euler angles, J2000.0 to specified date. */
77 0           eraPrec76(ERFA_DJ00, 0.0, date1, date2, &zeta, &z, &theta);
78              
79             /* Form the rotation matrix. */
80 0           eraIr( wmat);
81 0           eraRz( -zeta, wmat);
82 0           eraRy( theta, wmat);
83 0           eraRz( -z, wmat);
84 0           eraCr( wmat, rmatp);
85              
86 0           return;
87              
88             }
89             /*----------------------------------------------------------------------
90             **
91             **
92             ** Copyright (C) 2013-2019, NumFOCUS Foundation.
93             ** All rights reserved.
94             **
95             ** This library is derived, with permission, from the International
96             ** Astronomical Union's "Standards of Fundamental Astronomy" library,
97             ** available from http://www.iausofa.org.
98             **
99             ** The ERFA version is intended to retain identical functionality to
100             ** the SOFA library, but made distinct through different function and
101             ** file names, as set out in the SOFA license conditions. The SOFA
102             ** original has a role as a reference standard for the IAU and IERS,
103             ** and consequently redistribution is permitted only in its unaltered
104             ** state. The ERFA version is not subject to this restriction and
105             ** therefore can be included in distributions which do not support the
106             ** concept of "read only" software.
107             **
108             ** Although the intent is to replicate the SOFA API (other than
109             ** replacement of prefix names) and results (with the exception of
110             ** bugs; any that are discovered will be fixed), SOFA is not
111             ** responsible for any errors found in this version of the library.
112             **
113             ** If you wish to acknowledge the SOFA heritage, please acknowledge
114             ** that you are using a library derived from SOFA, rather than SOFA
115             ** itself.
116             **
117             **
118             ** TERMS AND CONDITIONS
119             **
120             ** Redistribution and use in source and binary forms, with or without
121             ** modification, are permitted provided that the following conditions
122             ** are met:
123             **
124             ** 1 Redistributions of source code must retain the above copyright
125             ** notice, this list of conditions and the following disclaimer.
126             **
127             ** 2 Redistributions in binary form must reproduce the above copyright
128             ** notice, this list of conditions and the following disclaimer in
129             ** the documentation and/or other materials provided with the
130             ** distribution.
131             **
132             ** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
133             ** the International Astronomical Union nor the names of its
134             ** contributors may be used to endorse or promote products derived
135             ** from this software without specific prior written permission.
136             **
137             ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
138             ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
139             ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
140             ** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
141             ** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
142             ** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
143             ** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
144             ** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
145             ** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
146             ** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
147             ** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
148             ** POSSIBILITY OF SUCH DAMAGE.
149             **
150             */