File Coverage

erfasrc/src/tdbtt.c

Criterion	Covered	Total	%
statement	0	8	0.0
branch	0	2	0.0
condition			n/a
subroutine			n/a
pod			n/a
total	0	10	0.0

line	stmt	bran	code
1			#include "erfa.h"
2
3	0		int eraTdbtt(double tdb1, double tdb2, double dtr,
4			double tt1, double tt2 )
5			/*
6			** - - - - - - - - -
7			** e r a T d b t t
8			** - - - - - - - - -
9			**
10			** Time scale transformation: Barycentric Dynamical Time, TDB, to
11			** Terrestrial Time, TT.
12			**
13			** Given:
14			** tdb1,tdb2 double TDB as a 2-part Julian Date
15			** dtr double TDB-TT in seconds
16			**
17			** Returned:
18			** tt1,tt2 double TT as a 2-part Julian Date
19			**
20			** Returned (function value):
21			** int status: 0 = OK
22			**
23			** Notes:
24			**
25			** 1) tdb1+tdb2 is Julian Date, apportioned in any convenient way
26			** between the two arguments, for example where tdb1 is the Julian
27			** Day Number and tdb2 is the fraction of a day. The returned
28			** tt1,tt2 follow suit.
29			**
30			** 2) The argument dtr represents the quasi-periodic component of the
31			** GR transformation between TT and TCB. It is dependent upon the
32			** adopted solar-system ephemeris, and can be obtained by numerical
33			** integration, by interrogating a precomputed time ephemeris or by
34			** evaluating a model such as that implemented in the ERFA function
35			** eraDtdb. The quantity is dominated by an annual term of 1.7 ms
36			** amplitude.
37			**
38			** 3) TDB is essentially the same as Teph, the time argument for the
39			** JPL solar system ephemerides.
40			**
41			** References:
42			**
43			** McCarthy, D. D., Petit, G. (eds.), IERS Conventions (2003),
44			** IERS Technical Note No. 32, BKG (2004)
45			**
46			** IAU 2006 Resolution 3
47			**
48			** Copyright (C) 2013-2019, NumFOCUS Foundation.
49			** Derived, with permission, from the SOFA library. See notes at end of file.
50			*/
51			{
52			double dtrd;
53
54
55			/* Result, safeguarding precision. */
56	0		dtrd = dtr / ERFA_DAYSEC;
57	0	0	if ( tdb1 > tdb2 ) {
58	0		*tt1 = tdb1;
59	0		*tt2 = tdb2 - dtrd;
60			} else {
61	0		*tt1 = tdb1 - dtrd;
62	0		*tt2 = tdb2;
63			}
64
65			/* Status (always OK). */
66	0		return 0;
67
68			}
69			/*----------------------------------------------------------------------
70			**
71			**
72			** Copyright (C) 2013-2019, NumFOCUS Foundation.
73			** All rights reserved.
74			**
75			** This library is derived, with permission, from the International
76			** Astronomical Union's "Standards of Fundamental Astronomy" library,
77			** available from http://www.iausofa.org.
78			**
79			** The ERFA version is intended to retain identical functionality to
80			** the SOFA library, but made distinct through different function and
81			** file names, as set out in the SOFA license conditions. The SOFA
82			** original has a role as a reference standard for the IAU and IERS,
83			** and consequently redistribution is permitted only in its unaltered
84			** state. The ERFA version is not subject to this restriction and
85			** therefore can be included in distributions which do not support the
86			** concept of "read only" software.
87			**
88			** Although the intent is to replicate the SOFA API (other than
89			** replacement of prefix names) and results (with the exception of
90			** bugs; any that are discovered will be fixed), SOFA is not
91			** responsible for any errors found in this version of the library.
92			**
93			** If you wish to acknowledge the SOFA heritage, please acknowledge
94			** that you are using a library derived from SOFA, rather than SOFA
95			** itself.
96			**
97			**
98			** TERMS AND CONDITIONS
99			**
100			** Redistribution and use in source and binary forms, with or without
101			** modification, are permitted provided that the following conditions
102			** are met:
103			**
104			** 1 Redistributions of source code must retain the above copyright
105			** notice, this list of conditions and the following disclaimer.
106			**
107			** 2 Redistributions in binary form must reproduce the above copyright
108			** notice, this list of conditions and the following disclaimer in
109			** the documentation and/or other materials provided with the
110			** distribution.
111			**
112			** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
113			** the International Astronomical Union nor the names of its
114			** contributors may be used to endorse or promote products derived
115			** from this software without specific prior written permission.
116			**
117			** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
118			** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
119			** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
120			** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
121			** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
122			** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
123			** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
124			** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
125			** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
126			** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
127			** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
128			** POSSIBILITY OF SUCH DAMAGE.
129			**
130			*/