File Coverage

erfasrc/src/gmst00.c
Criterion Covered Total %
statement 0 9 0.0
branch n/a
condition n/a
subroutine n/a
pod n/a
total 0 9 0.0


line stmt bran cond sub pod time code
1             #include "erfa.h"
2              
3 0           double eraGmst00(double uta, double utb, double tta, double ttb)
4             /*
5             ** - - - - - - - - - -
6             ** e r a G m s t 0 0
7             ** - - - - - - - - - -
8             **
9             ** Greenwich mean sidereal time (model consistent with IAU 2000
10             ** resolutions).
11             **
12             ** Given:
13             ** uta,utb double UT1 as a 2-part Julian Date (Notes 1,2)
14             ** tta,ttb double TT as a 2-part Julian Date (Notes 1,2)
15             **
16             ** Returned (function value):
17             ** double Greenwich mean sidereal time (radians)
18             **
19             ** Notes:
20             **
21             ** 1) The UT1 and TT dates uta+utb and tta+ttb respectively, are both
22             ** Julian Dates, apportioned in any convenient way between the
23             ** argument pairs. For example, JD=2450123.7 could be expressed in
24             ** any of these ways, among others:
25             **
26             ** Part A Part B
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 (in the case of UT; the TT is not at all critical
36             ** in this respect). The J2000 and MJD methods are good compromises
37             ** between resolution and convenience. For UT, the date & time
38             ** method is best matched to the algorithm that is used by the Earth
39             ** Rotation Angle function, called internally: maximum precision is
40             ** delivered when the uta argument is for 0hrs UT1 on the day in
41             ** question and the utb argument lies in the range 0 to 1, or vice
42             ** versa.
43             **
44             ** 2) Both UT1 and TT are required, UT1 to predict the Earth rotation
45             ** and TT to predict the effects of precession. If UT1 is used for
46             ** both purposes, errors of order 100 microarcseconds result.
47             **
48             ** 3) This GMST is compatible with the IAU 2000 resolutions and must be
49             ** used only in conjunction with other IAU 2000 compatible
50             ** components such as precession-nutation and equation of the
51             ** equinoxes.
52             **
53             ** 4) The result is returned in the range 0 to 2pi.
54             **
55             ** 5) The algorithm is from Capitaine et al. (2003) and IERS
56             ** Conventions 2003.
57             **
58             ** Called:
59             ** eraEra00 Earth rotation angle, IAU 2000
60             ** eraAnp normalize angle into range 0 to 2pi
61             **
62             ** References:
63             **
64             ** Capitaine, N., Wallace, P.T. and McCarthy, D.D., "Expressions to
65             ** implement the IAU 2000 definition of UT1", Astronomy &
66             ** Astrophysics, 406, 1135-1149 (2003)
67             **
68             ** McCarthy, D. D., Petit, G. (eds.), IERS Conventions (2003),
69             ** IERS Technical Note No. 32, BKG (2004)
70             **
71             ** Copyright (C) 2013-2020, NumFOCUS Foundation.
72             ** Derived, with permission, from the SOFA library. See notes at end of file.
73             */
74             {
75             double t, gmst;
76              
77              
78             /* TT Julian centuries since J2000.0. */
79 0           t = ((tta - ERFA_DJ00) + ttb) / ERFA_DJC;
80              
81             /* Greenwich Mean Sidereal Time, IAU 2000. */
82 0           gmst = eraAnp(eraEra00(uta, utb) +
83 0           ( 0.014506 +
84 0           ( 4612.15739966 +
85 0           ( 1.39667721 +
86 0           ( -0.00009344 +
87             ( 0.00001882 )
88 0           * t) * t) * t) * t) * ERFA_DAS2R);
89              
90 0           return gmst;
91              
92             }
93             /*----------------------------------------------------------------------
94             **
95             **
96             ** Copyright (C) 2013-2020, NumFOCUS Foundation.
97             ** All rights reserved.
98             **
99             ** This library is derived, with permission, from the International
100             ** Astronomical Union's "Standards of Fundamental Astronomy" library,
101             ** available from http://www.iausofa.org.
102             **
103             ** The ERFA version is intended to retain identical functionality to
104             ** the SOFA library, but made distinct through different function and
105             ** file names, as set out in the SOFA license conditions. The SOFA
106             ** original has a role as a reference standard for the IAU and IERS,
107             ** and consequently redistribution is permitted only in its unaltered
108             ** state. The ERFA version is not subject to this restriction and
109             ** therefore can be included in distributions which do not support the
110             ** concept of "read only" software.
111             **
112             ** Although the intent is to replicate the SOFA API (other than
113             ** replacement of prefix names) and results (with the exception of
114             ** bugs; any that are discovered will be fixed), SOFA is not
115             ** responsible for any errors found in this version of the library.
116             **
117             ** If you wish to acknowledge the SOFA heritage, please acknowledge
118             ** that you are using a library derived from SOFA, rather than SOFA
119             ** itself.
120             **
121             **
122             ** TERMS AND CONDITIONS
123             **
124             ** Redistribution and use in source and binary forms, with or without
125             ** modification, are permitted provided that the following conditions
126             ** are met:
127             **
128             ** 1 Redistributions of source code must retain the above copyright
129             ** notice, this list of conditions and the following disclaimer.
130             **
131             ** 2 Redistributions in binary form must reproduce the above copyright
132             ** notice, this list of conditions and the following disclaimer in
133             ** the documentation and/or other materials provided with the
134             ** distribution.
135             **
136             ** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
137             ** the International Astronomical Union nor the names of its
138             ** contributors may be used to endorse or promote products derived
139             ** from this software without specific prior written permission.
140             **
141             ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
142             ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
143             ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
144             ** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
145             ** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
146             ** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
147             ** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
148             ** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
149             ** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
150             ** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
151             ** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
152             ** POSSIBILITY OF SUCH DAMAGE.
153             **
154             */