File Coverage

erfasrc/src/pas.c
Criterion Covered Total %
statement 6 6 100.0
branch 1 2 50.0
condition n/a
subroutine n/a
pod n/a
total 7 8 87.5


line stmt bran cond sub pod time code
1             #include "erfa.h"
2              
3 1           double eraPas(double al, double ap, double bl, double bp)
4             /*
5             ** - - - - - - -
6             ** e r a P a s
7             ** - - - - - - -
8             **
9             ** Position-angle from spherical coordinates.
10             **
11             ** Given:
12             ** al double longitude of point A (e.g. RA) in radians
13             ** ap double latitude of point A (e.g. Dec) in radians
14             ** bl double longitude of point B
15             ** bp double latitude of point B
16             **
17             ** Returned (function value):
18             ** double position angle of B with respect to A
19             **
20             ** Notes:
21             **
22             ** 1) The result is the bearing (position angle), in radians, of point
23             ** B with respect to point A. It is in the range -pi to +pi. The
24             ** sense is such that if B is a small distance "east" of point A,
25             ** the bearing is approximately +pi/2.
26             **
27             ** 2) Zero is returned if the two points are coincident.
28             **
29             ** Copyright (C) 2013-2019, NumFOCUS Foundation.
30             ** Derived, with permission, from the SOFA library. See notes at end of file.
31             */
32             {
33             double dl, x, y, pa;
34              
35              
36 1           dl = bl - al;
37 1           y = sin(dl) * cos(bp);
38 1           x = sin(bp) * cos(ap) - cos(bp) * sin(ap) * cos(dl);
39 1 50         pa = ((x != 0.0) || (y != 0.0)) ? atan2(y, x) : 0.0;
40              
41 1           return pa;
42              
43             }
44             /*----------------------------------------------------------------------
45             **
46             **
47             ** Copyright (C) 2013-2019, NumFOCUS Foundation.
48             ** All rights reserved.
49             **
50             ** This library is derived, with permission, from the International
51             ** Astronomical Union's "Standards of Fundamental Astronomy" library,
52             ** available from http://www.iausofa.org.
53             **
54             ** The ERFA version is intended to retain identical functionality to
55             ** the SOFA library, but made distinct through different function and
56             ** file names, as set out in the SOFA license conditions. The SOFA
57             ** original has a role as a reference standard for the IAU and IERS,
58             ** and consequently redistribution is permitted only in its unaltered
59             ** state. The ERFA version is not subject to this restriction and
60             ** therefore can be included in distributions which do not support the
61             ** concept of "read only" software.
62             **
63             ** Although the intent is to replicate the SOFA API (other than
64             ** replacement of prefix names) and results (with the exception of
65             ** bugs; any that are discovered will be fixed), SOFA is not
66             ** responsible for any errors found in this version of the library.
67             **
68             ** If you wish to acknowledge the SOFA heritage, please acknowledge
69             ** that you are using a library derived from SOFA, rather than SOFA
70             ** itself.
71             **
72             **
73             ** TERMS AND CONDITIONS
74             **
75             ** Redistribution and use in source and binary forms, with or without
76             ** modification, are permitted provided that the following conditions
77             ** are met:
78             **
79             ** 1 Redistributions of source code must retain the above copyright
80             ** notice, this list of conditions and the following disclaimer.
81             **
82             ** 2 Redistributions in binary form must reproduce the above copyright
83             ** notice, this list of conditions and the following disclaimer in
84             ** the documentation and/or other materials provided with the
85             ** distribution.
86             **
87             ** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
88             ** the International Astronomical Union nor the names of its
89             ** contributors may be used to endorse or promote products derived
90             ** from this software without specific prior written permission.
91             **
92             ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
93             ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
94             ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
95             ** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
96             ** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
97             ** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
98             ** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
99             ** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
100             ** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
101             ** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
102             ** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
103             ** POSSIBILITY OF SUCH DAMAGE.
104             **
105             */