source: trunk/FACT++/erfa/src/taiut1.c@ 19713

Last change on this file since 19713 was 18921, checked in by tbretz, 7 years ago
Updated to ERFA 1.4.0
File size: 4.3 KB
Line 
1#include "erfa.h"
2
3int eraTaiut1(double tai1, double tai2, double dta,
4 double *ut11, double *ut12)
5/*
6** - - - - - - - - - -
7** e r a T a i u t 1
8** - - - - - - - - - -
9**
10** Time scale transformation: International Atomic Time, TAI, to
11** Universal Time, UT1.
12**
13** Given:
14** tai1,tai2 double TAI as a 2-part Julian Date
15** dta double UT1-TAI in seconds
16**
17** Returned:
18** ut11,ut12 double UT1 as a 2-part Julian Date
19**
20** Returned (function value):
21** int status: 0 = OK
22**
23** Notes:
24**
25** 1) tai1+tai2 is Julian Date, apportioned in any convenient way
26** between the two arguments, for example where tai1 is the Julian
27** Day Number and tai2 is the fraction of a day. The returned
28** UT11,UT12 follow suit.
29**
30** 2) The argument dta, i.e. UT1-TAI, is an observed quantity, and is
31** available from IERS tabulations.
32**
33** Reference:
34**
35** Explanatory Supplement to the Astronomical Almanac,
36** P. Kenneth Seidelmann (ed), University Science Books (1992)
37**
38** Copyright (C) 2013-2017, NumFOCUS Foundation.
39** Derived, with permission, from the SOFA library. See notes at end of file.
40*/
41{
42 double dtad;
43
44
45/* Result, safeguarding precision. */
46 dtad = dta / ERFA_DAYSEC;
47 if ( tai1 > tai2 ) {
48 *ut11 = tai1;
49 *ut12 = tai2 + dtad;
50 } else {
51 *ut11 = tai1 + dtad;
52 *ut12 = tai2;
53 }
54
55/* Status (always OK). */
56 return 0;
57
58}
59/*----------------------------------------------------------------------
60**
61**
62** Copyright (C) 2013-2017, NumFOCUS Foundation.
63** All rights reserved.
64**
65** This library is derived, with permission, from the International
66** Astronomical Union's "Standards of Fundamental Astronomy" library,
67** available from http://www.iausofa.org.
68**
69** The ERFA version is intended to retain identical functionality to
70** the SOFA library, but made distinct through different function and
71** file names, as set out in the SOFA license conditions. The SOFA
72** original has a role as a reference standard for the IAU and IERS,
73** and consequently redistribution is permitted only in its unaltered
74** state. The ERFA version is not subject to this restriction and
75** therefore can be included in distributions which do not support the
76** concept of "read only" software.
77**
78** Although the intent is to replicate the SOFA API (other than
79** replacement of prefix names) and results (with the exception of
80** bugs; any that are discovered will be fixed), SOFA is not
81** responsible for any errors found in this version of the library.
82**
83** If you wish to acknowledge the SOFA heritage, please acknowledge
84** that you are using a library derived from SOFA, rather than SOFA
85** itself.
86**
87**
88** TERMS AND CONDITIONS
89**
90** Redistribution and use in source and binary forms, with or without
91** modification, are permitted provided that the following conditions
92** are met:
93**
94** 1 Redistributions of source code must retain the above copyright
95** notice, this list of conditions and the following disclaimer.
96**
97** 2 Redistributions in binary form must reproduce the above copyright
98** notice, this list of conditions and the following disclaimer in
99** the documentation and/or other materials provided with the
100** distribution.
101**
102** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
103** the International Astronomical Union nor the names of its
104** contributors may be used to endorse or promote products derived
105** from this software without specific prior written permission.
106**
107** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
108** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
109** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
110** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
111** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
112** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
113** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
114** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
115** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
116** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
117** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
118** POSSIBILITY OF SUCH DAMAGE.
119**
120*/
Note: See TracBrowser for help on using the repository browser.