File Coverage

erfasrc/src/eo06a.c

Criterion	Covered	Total	%
statement	0	6	0.0
branch			n/a
condition			n/a
subroutine			n/a
pod			n/a
total	0	6	0.0

line	stmt	code
1		#include "erfa.h"
2
3	0	double eraEo06a(double date1, double date2)
4		/*
5		** - - - - - - - - -
6		** e r a E o 0 6 a
7		** - - - - - - - - -
8		**
9		** Equation of the origins, IAU 2006 precession and IAU 2000A nutation.
10		**
11		** Given:
12		** date1,date2 double TT as a 2-part Julian Date (Note 1)
13		**
14		** Returned (function value):
15		** double equation of the origins in radians
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 equation of the origins is the distance between the true
39		** equinox and the celestial intermediate origin and, equivalently,
40		** the difference between Earth rotation angle and Greenwich
41		** apparent sidereal time (ERA-GST). It comprises the precession
42		** (since J2000.0) in right ascension plus the equation of the
43		** equinoxes (including the small correction terms).
44		**
45		** Called:
46		** eraPnm06a classical NPB matrix, IAU 2006/2000A
47		** eraBpn2xy extract CIP X,Y coordinates from NPB matrix
48		** eraS06 the CIO locator s, given X,Y, IAU 2006
49		** eraEors equation of the origins, given NPB matrix and s
50		**
51		** References:
52		**
53		** Capitaine, N. & Wallace, P.T., 2006, Astron.Astrophys. 450, 855
54		**
55		** Wallace, P.T. & Capitaine, N., 2006, Astron.Astrophys. 459, 981
56		**
57		** Copyright (C) 2013-2020, NumFOCUS Foundation.
58		** Derived, with permission, from the SOFA library. See notes at end of file.
59		*/
60		{
61		double r[3][3], x, y, s, eo;
62
63
64		/* Classical nutation x precession x bias matrix. */
65	0	eraPnm06a(date1, date2, r);
66
67		/* Extract CIP coordinates. */
68	0	eraBpn2xy(r, &x, &y);
69
70		/* The CIO locator, s. */
71	0	s = eraS06(date1, date2, x, y);
72
73		/* Solve for the EO. */
74	0	eo = eraEors(r, s);
75
76	0	return eo;
77
78		}
79		/*----------------------------------------------------------------------
80		**
81		**
82		** Copyright (C) 2013-2020, NumFOCUS Foundation.
83		** All rights reserved.
84		**
85		** This library is derived, with permission, from the International
86		** Astronomical Union's "Standards of Fundamental Astronomy" library,
87		** available from http://www.iausofa.org.
88		**
89		** The ERFA version is intended to retain identical functionality to
90		** the SOFA library, but made distinct through different function and
91		** file names, as set out in the SOFA license conditions. The SOFA
92		** original has a role as a reference standard for the IAU and IERS,
93		** and consequently redistribution is permitted only in its unaltered
94		** state. The ERFA version is not subject to this restriction and
95		** therefore can be included in distributions which do not support the
96		** concept of "read only" software.
97		**
98		** Although the intent is to replicate the SOFA API (other than
99		** replacement of prefix names) and results (with the exception of
100		** bugs; any that are discovered will be fixed), SOFA is not
101		** responsible for any errors found in this version of the library.
102		**
103		** If you wish to acknowledge the SOFA heritage, please acknowledge
104		** that you are using a library derived from SOFA, rather than SOFA
105		** itself.
106		**
107		**
108		** TERMS AND CONDITIONS
109		**
110		** Redistribution and use in source and binary forms, with or without
111		** modification, are permitted provided that the following conditions
112		** are met:
113		**
114		** 1 Redistributions of source code must retain the above copyright
115		** notice, this list of conditions and the following disclaimer.
116		**
117		** 2 Redistributions in binary form must reproduce the above copyright
118		** notice, this list of conditions and the following disclaimer in
119		** the documentation and/or other materials provided with the
120		** distribution.
121		**
122		** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
123		** the International Astronomical Union nor the names of its
124		** contributors may be used to endorse or promote products derived
125		** from this software without specific prior written permission.
126		**
127		** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
128		** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
129		** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
130		** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
131		** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
132		** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
133		** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
134		** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
135		** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
136		** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
137		** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
138		** POSSIBILITY OF SUCH DAMAGE.
139		**
140		*/