File Coverage

erfasrc/src/gmst06.c
Criterion Covered Total %
statement 10 10 100.0
branch n/a
condition n/a
subroutine n/a
pod n/a
total 10 10 100.0


line stmt bran cond sub pod time code
1             #include "erfa.h"
2              
3 16           double eraGmst06(double uta, double utb, double tta, double ttb)
4             /*
5             ** - - - - - - - - - -
6             ** e r a G m s t 0 6
7             ** - - - - - - - - - -
8             **
9             ** Greenwich mean sidereal time (consistent with IAU 2006 precession).
10             **
11             ** Given:
12             ** uta,utb double UT1 as a 2-part Julian Date (Notes 1,2)
13             ** tta,ttb double TT as a 2-part Julian Date (Notes 1,2)
14             **
15             ** Returned (function value):
16             ** double Greenwich mean sidereal time (radians)
17             **
18             ** Notes:
19             **
20             ** 1) The UT1 and TT dates uta+utb and tta+ttb respectively, are both
21             ** Julian Dates, apportioned in any convenient way between the
22             ** argument pairs. For example, JD=2450123.7 could be expressed in
23             ** any of these ways, among others:
24             **
25             ** Part A Part B
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 (in the case of UT; the TT is not at all critical
35             ** in this respect). The J2000 and MJD methods are good compromises
36             ** between resolution and convenience. For UT, the date & time
37             ** method is best matched to the algorithm that is used by the Earth
38             ** rotation angle function, called internally: maximum precision is
39             ** delivered when the uta argument is for 0hrs UT1 on the day in
40             ** question and the utb argument lies in the range 0 to 1, or vice
41             ** versa.
42             **
43             ** 2) Both UT1 and TT are required, UT1 to predict the Earth rotation
44             ** and TT to predict the effects of precession. If UT1 is used for
45             ** both purposes, errors of order 100 microarcseconds result.
46             **
47             ** 3) This GMST is compatible with the IAU 2006 precession and must not
48             ** be used with other precession models.
49             **
50             ** 4) The result is returned in the range 0 to 2pi.
51             **
52             ** Called:
53             ** eraEra00 Earth rotation angle, IAU 2000
54             ** eraAnp normalize angle into range 0 to 2pi
55             **
56             ** Reference:
57             **
58             ** Capitaine, N., Wallace, P.T. & Chapront, J., 2005,
59             ** Astron.Astrophys. 432, 355
60             **
61             ** Copyright (C) 2013-2019, NumFOCUS Foundation.
62             ** Derived, with permission, from the SOFA library. See notes at end of file.
63             */
64             {
65             double t, gmst;
66              
67              
68             /* TT Julian centuries since J2000.0. */
69 16           t = ((tta - ERFA_DJ00) + ttb) / ERFA_DJC;
70              
71             /* Greenwich mean sidereal time, IAU 2006. */
72 16           gmst = eraAnp(eraEra00(uta, utb) +
73 16           ( 0.014506 +
74 16           ( 4612.156534 +
75 16           ( 1.3915817 +
76 16           ( -0.00000044 +
77 16           ( -0.000029956 +
78             ( -0.0000000368 )
79 96           * t) * t) * t) * t) * t) * ERFA_DAS2R);
80              
81 16           return gmst;
82              
83             }
84             /*----------------------------------------------------------------------
85             **
86             **
87             ** Copyright (C) 2013-2019, NumFOCUS Foundation.
88             ** All rights reserved.
89             **
90             ** This library is derived, with permission, from the International
91             ** Astronomical Union's "Standards of Fundamental Astronomy" library,
92             ** available from http://www.iausofa.org.
93             **
94             ** The ERFA version is intended to retain identical functionality to
95             ** the SOFA library, but made distinct through different function and
96             ** file names, as set out in the SOFA license conditions. The SOFA
97             ** original has a role as a reference standard for the IAU and IERS,
98             ** and consequently redistribution is permitted only in its unaltered
99             ** state. The ERFA version is not subject to this restriction and
100             ** therefore can be included in distributions which do not support the
101             ** concept of "read only" software.
102             **
103             ** Although the intent is to replicate the SOFA API (other than
104             ** replacement of prefix names) and results (with the exception of
105             ** bugs; any that are discovered will be fixed), SOFA is not
106             ** responsible for any errors found in this version of the library.
107             **
108             ** If you wish to acknowledge the SOFA heritage, please acknowledge
109             ** that you are using a library derived from SOFA, rather than SOFA
110             ** itself.
111             **
112             **
113             ** TERMS AND CONDITIONS
114             **
115             ** Redistribution and use in source and binary forms, with or without
116             ** modification, are permitted provided that the following conditions
117             ** are met:
118             **
119             ** 1 Redistributions of source code must retain the above copyright
120             ** notice, this list of conditions and the following disclaimer.
121             **
122             ** 2 Redistributions in binary form must reproduce the above copyright
123             ** notice, this list of conditions and the following disclaimer in
124             ** the documentation and/or other materials provided with the
125             ** distribution.
126             **
127             ** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
128             ** the International Astronomical Union nor the names of its
129             ** contributors may be used to endorse or promote products derived
130             ** from this software without specific prior written permission.
131             **
132             ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
133             ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
134             ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
135             ** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
136             ** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
137             ** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
138             ** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
139             ** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
140             ** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
141             ** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
142             ** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
143             ** POSSIBILITY OF SUCH DAMAGE.
144             **
145             */