File Coverage

erfasrc/src/pr00.c
Criterion Covered Total %
statement 0 5 0.0
branch n/a
condition n/a
subroutine n/a
pod n/a
total 0 5 0.0


line stmt bran cond sub pod time code
1             #include "erfa.h"
2              
3 0           void eraPr00(double date1, double date2, double *dpsipr, double *depspr)
4             /*
5             ** - - - - - - - -
6             ** e r a P r 0 0
7             ** - - - - - - - -
8             **
9             ** Precession-rate part of the IAU 2000 precession-nutation models
10             ** (part of MHB2000).
11             **
12             ** Given:
13             ** date1,date2 double TT as a 2-part Julian Date (Note 1)
14             **
15             ** Returned:
16             ** dpsipr,depspr double precession corrections (Notes 2,3)
17             **
18             ** Notes:
19             **
20             ** 1) The TT date date1+date2 is a Julian Date, apportioned in any
21             ** convenient way between the two arguments. For example,
22             ** JD(TT)=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 precession adjustments are expressed as "nutation
40             ** components", corrections in longitude and obliquity with respect
41             ** to the J2000.0 equinox and ecliptic.
42             **
43             ** 3) Although the precession adjustments are stated to be with respect
44             ** to Lieske et al. (1977), the MHB2000 model does not specify which
45             ** set of Euler angles are to be used and how the adjustments are to
46             ** be applied. The most literal and straightforward procedure is to
47             ** adopt the 4-rotation epsilon_0, psi_A, omega_A, xi_A option, and
48             ** to add dpsipr to psi_A and depspr to both omega_A and eps_A.
49             **
50             ** 4) This is an implementation of one aspect of the IAU 2000A nutation
51             ** model, formally adopted by the IAU General Assembly in 2000,
52             ** namely MHB2000 (Mathews et al. 2002).
53             **
54             ** References:
55             **
56             ** Lieske, J.H., Lederle, T., Fricke, W. & Morando, B., "Expressions
57             ** for the precession quantities based upon the IAU (1976) System of
58             ** Astronomical Constants", Astron.Astrophys., 58, 1-16 (1977)
59             **
60             ** Mathews, P.M., Herring, T.A., Buffet, B.A., "Modeling of nutation
61             ** and precession New nutation series for nonrigid Earth and
62             ** insights into the Earth's interior", J.Geophys.Res., 107, B4,
63             ** 2002. The MHB2000 code itself was obtained on 9th September 2002
64             ** from ftp://maia.usno.navy.mil/conv2000/chapter5/IAU2000A.
65             **
66             ** Wallace, P.T., "Software for Implementing the IAU 2000
67             ** Resolutions", in IERS Workshop 5.1 (2002).
68             **
69             ** Copyright (C) 2013-2020, NumFOCUS Foundation.
70             ** Derived, with permission, from the SOFA library. See notes at end of file.
71             */
72             {
73             double t;
74              
75             /* Precession and obliquity corrections (radians per century) */
76             static const double PRECOR = -0.29965 * ERFA_DAS2R,
77             OBLCOR = -0.02524 * ERFA_DAS2R;
78              
79              
80             /* Interval between fundamental epoch J2000.0 and given date (JC). */
81 0           t = ((date1 - ERFA_DJ00) + date2) / ERFA_DJC;
82              
83             /* Precession rate contributions with respect to IAU 1976/80. */
84 0           *dpsipr = PRECOR * t;
85 0           *depspr = OBLCOR * t;
86              
87 0           return;
88              
89             }
90             /*----------------------------------------------------------------------
91             **
92             **
93             ** Copyright (C) 2013-2020, NumFOCUS Foundation.
94             ** All rights reserved.
95             **
96             ** This library is derived, with permission, from the International
97             ** Astronomical Union's "Standards of Fundamental Astronomy" library,
98             ** available from http://www.iausofa.org.
99             **
100             ** The ERFA version is intended to retain identical functionality to
101             ** the SOFA library, but made distinct through different function and
102             ** file names, as set out in the SOFA license conditions. The SOFA
103             ** original has a role as a reference standard for the IAU and IERS,
104             ** and consequently redistribution is permitted only in its unaltered
105             ** state. The ERFA version is not subject to this restriction and
106             ** therefore can be included in distributions which do not support the
107             ** concept of "read only" software.
108             **
109             ** Although the intent is to replicate the SOFA API (other than
110             ** replacement of prefix names) and results (with the exception of
111             ** bugs; any that are discovered will be fixed), SOFA is not
112             ** responsible for any errors found in this version of the library.
113             **
114             ** If you wish to acknowledge the SOFA heritage, please acknowledge
115             ** that you are using a library derived from SOFA, rather than SOFA
116             ** itself.
117             **
118             **
119             ** TERMS AND CONDITIONS
120             **
121             ** Redistribution and use in source and binary forms, with or without
122             ** modification, are permitted provided that the following conditions
123             ** are met:
124             **
125             ** 1 Redistributions of source code must retain the above copyright
126             ** notice, this list of conditions and the following disclaimer.
127             **
128             ** 2 Redistributions in binary form must reproduce the above copyright
129             ** notice, this list of conditions and the following disclaimer in
130             ** the documentation and/or other materials provided with the
131             ** distribution.
132             **
133             ** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
134             ** the International Astronomical Union nor the names of its
135             ** contributors may be used to endorse or promote products derived
136             ** from this software without specific prior written permission.
137             **
138             ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
139             ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
140             ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
141             ** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
142             ** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
143             ** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
144             ** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
145             ** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
146             ** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
147             ** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
148             ** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
149             ** POSSIBILITY OF SUCH DAMAGE.
150             **
151             */