File Coverage

erfasrc/src/xys00a.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	code
1		#include "erfa.h"
2
3	0	void eraXys00a(double date1, double date2,
4		double x, double y, double *s)
5		/*
6		** - - - - - - - - - -
7		** e r a X y s 0 0 a
8		** - - - - - - - - - -
9		**
10		** For a given TT date, compute the X,Y coordinates of the Celestial
11		** Intermediate Pole and the CIO locator s, using the IAU 2000A
12		** precession-nutation model.
13		**
14		** Given:
15		** date1,date2 double TT as a 2-part Julian Date (Note 1)
16		**
17		** Returned:
18		** x,y double Celestial Intermediate Pole (Note 2)
19		** s double the CIO locator s (Note 3)
20		**
21		** Notes:
22		**
23		** 1) The TT date date1+date2 is a Julian Date, apportioned in any
24		** convenient way between the two arguments. For example,
25		** JD(TT)=2450123.7 could be expressed in any of these ways,
26		** among others:
27		**
28		** date1 date2
29		**
30		** 2450123.7 0.0 (JD method)
31		** 2451545.0 -1421.3 (J2000 method)
32		** 2400000.5 50123.2 (MJD method)
33		** 2450123.5 0.2 (date & time method)
34		**
35		** The JD method is the most natural and convenient to use in
36		** cases where the loss of several decimal digits of resolution
37		** is acceptable. The J2000 method is best matched to the way
38		** the argument is handled internally and will deliver the
39		** optimum resolution. The MJD method and the date & time methods
40		** are both good compromises between resolution and convenience.
41		**
42		** 2) The Celestial Intermediate Pole coordinates are the x,y
43		** components of the unit vector in the Geocentric Celestial
44		** Reference System.
45		**
46		** 3) The CIO locator s (in radians) positions the Celestial
47		** Intermediate Origin on the equator of the CIP.
48		**
49		** 4) A faster, but slightly less accurate result (about 1 mas for
50		** X,Y), can be obtained by using instead the eraXys00b function.
51		**
52		** Called:
53		** eraPnm00a classical NPB matrix, IAU 2000A
54		** eraBpn2xy extract CIP X,Y coordinates from NPB matrix
55		** eraS00 the CIO locator s, given X,Y, IAU 2000A
56		**
57		** Reference:
58		**
59		** McCarthy, D. D., Petit, G. (eds.), IERS Conventions (2003),
60		** IERS Technical Note No. 32, BKG (2004)
61		**
62		** Copyright (C) 2013-2020, NumFOCUS Foundation.
63		** Derived, with permission, from the SOFA library. See notes at end of file.
64		*/
65		{
66		double rbpn[3][3];
67
68
69		/* Form the bias-precession-nutation matrix, IAU 2000A. */
70	0	eraPnm00a(date1, date2, rbpn);
71
72		/* Extract X,Y. */
73	0	eraBpn2xy(rbpn, x, y);
74
75		/* Obtain s. */
76	0	s = eraS00(date1, date2, x, *y);
77
78	0	return;
79
80		}
81		/*----------------------------------------------------------------------
82		**
83		**
84		** Copyright (C) 2013-2020, NumFOCUS Foundation.
85		** All rights reserved.
86		**
87		** This library is derived, with permission, from the International
88		** Astronomical Union's "Standards of Fundamental Astronomy" library,
89		** available from http://www.iausofa.org.
90		**
91		** The ERFA version is intended to retain identical functionality to
92		** the SOFA library, but made distinct through different function and
93		** file names, as set out in the SOFA license conditions. The SOFA
94		** original has a role as a reference standard for the IAU and IERS,
95		** and consequently redistribution is permitted only in its unaltered
96		** state. The ERFA version is not subject to this restriction and
97		** therefore can be included in distributions which do not support the
98		** concept of "read only" software.
99		**
100		** Although the intent is to replicate the SOFA API (other than
101		** replacement of prefix names) and results (with the exception of
102		** bugs; any that are discovered will be fixed), SOFA is not
103		** responsible for any errors found in this version of the library.
104		**
105		** If you wish to acknowledge the SOFA heritage, please acknowledge
106		** that you are using a library derived from SOFA, rather than SOFA
107		** itself.
108		**
109		**
110		** TERMS AND CONDITIONS
111		**
112		** Redistribution and use in source and binary forms, with or without
113		** modification, are permitted provided that the following conditions
114		** are met:
115		**
116		** 1 Redistributions of source code must retain the above copyright
117		** notice, this list of conditions and the following disclaimer.
118		**
119		** 2 Redistributions in binary form must reproduce the above copyright
120		** notice, this list of conditions and the following disclaimer in
121		** the documentation and/or other materials provided with the
122		** distribution.
123		**
124		** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
125		** the International Astronomical Union nor the names of its
126		** contributors may be used to endorse or promote products derived
127		** from this software without specific prior written permission.
128		**
129		** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
130		** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
131		** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
132		** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
133		** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
134		** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
135		** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
136		** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
137		** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
138		** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
139		** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
140		** POSSIBILITY OF SUCH DAMAGE.
141		**
142		*/