File Coverage

erfasrc/src/eqec06.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	code
1		#include "erfa.h"
2
3	0	void eraEqec06(double date1, double date2, double dr, double dd,
4		double dl, double db)
5		/*
6		** - - - - - - - - - -
7		** e r a E q e c 0 6
8		** - - - - - - - - - -
9		**
10		** Transformation from ICRS equatorial coordinates to ecliptic
11		** coordinates (mean equinox and ecliptic of date) using IAU 2006
12		** precession model.
13		**
14		** Given:
15		** date1,date2 double TT as a 2-part Julian date (Note 1)
16		** dr,dd double ICRS right ascension and declination (radians)
17		**
18		** Returned:
19		** dl,db double ecliptic longitude and latitude (radians)
20		**
21		** 1) The TT date date1+date2 is a Julian Date, apportioned in any
22		** convenient way between the two arguments. For example,
23		** JD(TT)=2450123.7 could be expressed in any of these ways,
24		** among others:
25		**
26		** date1 date2
27		**
28		** 2450123.7 0.0 (JD method)
29		** 2451545.0 -1421.3 (J2000 method)
30		** 2400000.5 50123.2 (MJD method)
31		** 2450123.5 0.2 (date & time method)
32		**
33		** The JD method is the most natural and convenient to use in
34		** cases where the loss of several decimal digits of resolution
35		** is acceptable. The J2000 method is best matched to the way
36		** the argument is handled internally and will deliver the
37		** optimum resolution. The MJD method and the date & time methods
38		** are both good compromises between resolution and convenience.
39		**
40		** 2) No assumptions are made about whether the coordinates represent
41		** starlight and embody astrometric effects such as parallax or
42		** aberration.
43		**
44		** 3) The transformation is approximately that from mean J2000.0 right
45		** ascension and declination to ecliptic longitude and latitude
46		** (mean equinox and ecliptic of date), with only frame bias (always
47		** less than 25 mas) to disturb this classical picture.
48		**
49		** Called:
50		** eraS2c spherical coordinates to unit vector
51		** eraEcm06 J2000.0 to ecliptic rotation matrix, IAU 2006
52		** eraRxp product of r-matrix and p-vector
53		** eraC2s unit vector to spherical coordinates
54		** eraAnp normalize angle into range 0 to 2pi
55		** eraAnpm normalize angle into range +/- pi
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 rm[3][3], v1[3], v2[3], a, b;
62
63
64		/* Spherical to Cartesian. */
65	0	eraS2c(dr, dd, v1);
66
67		/* Rotation matrix, ICRS equatorial to ecliptic. */
68	0	eraEcm06(date1, date2, rm);
69
70		/* The transformation from ICRS to ecliptic. */
71	0	eraRxp(rm, v1, v2);
72
73		/* Cartesian to spherical. */
74	0	eraC2s(v2, &a, &b);
75
76		/* Express in conventional ranges. */
77	0	*dl = eraAnp(a);
78	0	*db = eraAnpm(b);
79
80	0	}
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		*/