File Coverage

erfasrc/src/sepp.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              
3 181           double eraSepp(double a[3], double b[3])
4             /*
5             ** - - - - - - - -
6             ** e r a S e p p
7             ** - - - - - - - -
8             **
9             ** Angular separation between two p-vectors.
10             **
11             ** Given:
12             ** a double[3] first p-vector (not necessarily unit length)
13             ** b double[3] second p-vector (not necessarily unit length)
14             **
15             ** Returned (function value):
16             ** double angular separation (radians, always positive)
17             **
18             ** Notes:
19             **
20             ** 1) If either vector is null, a zero result is returned.
21             **
22             ** 2) The angular separation is most simply formulated in terms of
23             ** scalar product. However, this gives poor accuracy for angles
24             ** near zero and pi. The present algorithm uses both cross product
25             ** and dot product, to deliver full accuracy whatever the size of
26             ** the angle.
27             **
28             ** Called:
29             ** eraPxp vector product of two p-vectors
30             ** eraPm modulus of p-vector
31             ** eraPdp scalar product of two p-vectors
32             **
33             ** Copyright (C) 2013-2020, NumFOCUS Foundation.
34             ** Derived, with permission, from the SOFA library. See notes at end of file.
35             */
36             {
37             double axb[3], ss, cs, s;
38              
39              
40             /* Sine of angle between the vectors, multiplied by the two moduli. */
41 181           eraPxp(a, b, axb);
42 181           ss = eraPm(axb);
43              
44             /* Cosine of the angle, multiplied by the two moduli. */
45 181           cs = eraPdp(a, b);
46              
47             /* The angle. */
48 181 50         s = ((ss != 0.0) || (cs != 0.0)) ? atan2(ss, cs) : 0.0;
49              
50 181           return s;
51              
52             }
53             /*----------------------------------------------------------------------
54             **
55             **
56             ** Copyright (C) 2013-2020, NumFOCUS Foundation.
57             ** All rights reserved.
58             **
59             ** This library is derived, with permission, from the International
60             ** Astronomical Union's "Standards of Fundamental Astronomy" library,
61             ** available from http://www.iausofa.org.
62             **
63             ** The ERFA version is intended to retain identical functionality to
64             ** the SOFA library, but made distinct through different function and
65             ** file names, as set out in the SOFA license conditions. The SOFA
66             ** original has a role as a reference standard for the IAU and IERS,
67             ** and consequently redistribution is permitted only in its unaltered
68             ** state. The ERFA version is not subject to this restriction and
69             ** therefore can be included in distributions which do not support the
70             ** concept of "read only" software.
71             **
72             ** Although the intent is to replicate the SOFA API (other than
73             ** replacement of prefix names) and results (with the exception of
74             ** bugs; any that are discovered will be fixed), SOFA is not
75             ** responsible for any errors found in this version of the library.
76             **
77             ** If you wish to acknowledge the SOFA heritage, please acknowledge
78             ** that you are using a library derived from SOFA, rather than SOFA
79             ** itself.
80             **
81             **
82             ** TERMS AND CONDITIONS
83             **
84             ** Redistribution and use in source and binary forms, with or without
85             ** modification, are permitted provided that the following conditions
86             ** are met:
87             **
88             ** 1 Redistributions of source code must retain the above copyright
89             ** notice, this list of conditions and the following disclaimer.
90             **
91             ** 2 Redistributions in binary form must reproduce the above copyright
92             ** notice, this list of conditions and the following disclaimer in
93             ** the documentation and/or other materials provided with the
94             ** distribution.
95             **
96             ** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
97             ** the International Astronomical Union nor the names of its
98             ** contributors may be used to endorse or promote products derived
99             ** from this software without specific prior written permission.
100             **
101             ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
102             ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
103             ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
104             ** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
105             ** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
106             ** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
107             ** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
108             ** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
109             ** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
110             ** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
111             ** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
112             ** POSSIBILITY OF SUCH DAMAGE.
113             **
114             */