source: trunk/FACT++/erfa/src/pvxpv.c@ 18403

Last change on this file since 18403 was 18348, checked in by tbretz, 9 years ago
File size: 4.3 KB
Line 
1#include "erfa.h"
2
3void eraPvxpv(double a[2][3], double b[2][3], double axb[2][3])
4/*
5** - - - - - - - - -
6** e r a P v x p v
7** - - - - - - - - -
8**
9** Outer (=vector=cross) product of two pv-vectors.
10**
11** Given:
12** a double[2][3] first pv-vector
13** b double[2][3] second pv-vector
14**
15** Returned:
16** axb double[2][3] a x b
17**
18** Notes:
19**
20** 1) If the position and velocity components of the two pv-vectors are
21** ( ap, av ) and ( bp, bv ), the result, a x b, is the pair of
22** vectors ( ap x bp, ap x bv + av x bp ). The two vectors are the
23** cross-product of the two p-vectors and its derivative.
24**
25** 2) It is permissible to re-use the same array for any of the
26** arguments.
27**
28** Called:
29** eraCpv copy pv-vector
30** eraPxp vector product of two p-vectors
31** eraPpp p-vector plus p-vector
32**
33** Copyright (C) 2013-2015, NumFOCUS Foundation.
34** Derived, with permission, from the SOFA library. See notes at end of file.
35*/
36{
37 double wa[2][3], wb[2][3], axbd[3], adxb[3];
38
39/* Make copies of the inputs. */
40 eraCpv(a, wa);
41 eraCpv(b, wb);
42
43/* a x b = position part of result. */
44 eraPxp(wa[0], wb[0], axb[0]);
45
46/* a x bdot + adot x b = velocity part of result. */
47 eraPxp(wa[0], wb[1], axbd);
48 eraPxp(wa[1], wb[0], adxb);
49 eraPpp(axbd, adxb, axb[1]);
50
51 return;
52
53}
54/*----------------------------------------------------------------------
55**
56**
57** Copyright (C) 2013-2015, NumFOCUS Foundation.
58** All rights reserved.
59**
60** This library is derived, with permission, from the International
61** Astronomical Union's "Standards of Fundamental Astronomy" library,
62** available from http://www.iausofa.org.
63**
64** The ERFA version is intended to retain identical functionality to
65** the SOFA library, but made distinct through different function and
66** file names, as set out in the SOFA license conditions. The SOFA
67** original has a role as a reference standard for the IAU and IERS,
68** and consequently redistribution is permitted only in its unaltered
69** state. The ERFA version is not subject to this restriction and
70** therefore can be included in distributions which do not support the
71** concept of "read only" software.
72**
73** Although the intent is to replicate the SOFA API (other than
74** replacement of prefix names) and results (with the exception of
75** bugs; any that are discovered will be fixed), SOFA is not
76** responsible for any errors found in this version of the library.
77**
78** If you wish to acknowledge the SOFA heritage, please acknowledge
79** that you are using a library derived from SOFA, rather than SOFA
80** itself.
81**
82**
83** TERMS AND CONDITIONS
84**
85** Redistribution and use in source and binary forms, with or without
86** modification, are permitted provided that the following conditions
87** are met:
88**
89** 1 Redistributions of source code must retain the above copyright
90** notice, this list of conditions and the following disclaimer.
91**
92** 2 Redistributions in binary form must reproduce the above copyright
93** notice, this list of conditions and the following disclaimer in
94** the documentation and/or other materials provided with the
95** distribution.
96**
97** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
98** the International Astronomical Union nor the names of its
99** contributors may be used to endorse or promote products derived
100** from this software without specific prior written permission.
101**
102** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
103** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
104** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
105** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
106** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
107** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
108** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
109** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
110** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
111** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
112** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
113** POSSIBILITY OF SUCH DAMAGE.
114**
115*/
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