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author | William Joye <wjoye@cfa.harvard.edu> | 2018-01-09 19:06:55 (GMT) |
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committer | William Joye <wjoye@cfa.harvard.edu> | 2018-01-09 19:06:55 (GMT) |
commit | 01e0ebfe59d9028b0246ec4a549bd7528ada94eb (patch) | |
tree | a6c5b54db03177a1c8f3e7fb531990dfbc7bae39 /ast/erfa/c2s.c | |
parent | d64cf9c0bd23e752867b149be636d1bbd4501cf4 (diff) | |
download | blt-01e0ebfe59d9028b0246ec4a549bd7528ada94eb.zip blt-01e0ebfe59d9028b0246ec4a549bd7528ada94eb.tar.gz blt-01e0ebfe59d9028b0246ec4a549bd7528ada94eb.tar.bz2 |
update ast 8.6.2
Diffstat (limited to 'ast/erfa/c2s.c')
-rw-r--r-- | ast/erfa/c2s.c | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/ast/erfa/c2s.c b/ast/erfa/c2s.c new file mode 100644 index 0000000..6f31a2b --- /dev/null +++ b/ast/erfa/c2s.c @@ -0,0 +1,105 @@ +#include "erfa.h" + +void eraC2s(double p[3], double *theta, double *phi) +/* +** - - - - - - - +** e r a C 2 s +** - - - - - - - +** +** P-vector to spherical coordinates. +** +** Given: +** p double[3] p-vector +** +** Returned: +** theta double longitude angle (radians) +** phi double latitude angle (radians) +** +** Notes: +** +** 1) The vector p can have any magnitude; only its direction is used. +** +** 2) If p is null, zero theta and phi are returned. +** +** 3) At either pole, zero theta is returned. +** +** Copyright (C) 2013-2016, NumFOCUS Foundation. +** Derived, with permission, from the SOFA library. See notes at end of file. +*/ +{ + double x, y, z, d2; + + + x = p[0]; + y = p[1]; + z = p[2]; + d2 = x*x + y*y; + + *theta = (d2 == 0.0) ? 0.0 : atan2(y, x); + *phi = (z == 0.0) ? 0.0 : atan2(z, sqrt(d2)); + + return; + +} +/*---------------------------------------------------------------------- +** +** +** Copyright (C) 2013-2016, NumFOCUS Foundation. +** All rights reserved. +** +** This library is derived, with permission, from the International +** Astronomical Union's "Standards of Fundamental Astronomy" library, +** available from http://www.iausofa.org. +** +** The ERFA version is intended to retain identical functionality to +** the SOFA library, but made distinct through different function and +** file names, as set out in the SOFA license conditions. The SOFA +** original has a role as a reference standard for the IAU and IERS, +** and consequently redistribution is permitted only in its unaltered +** state. The ERFA version is not subject to this restriction and +** therefore can be included in distributions which do not support the +** concept of "read only" software. +** +** Although the intent is to replicate the SOFA API (other than +** replacement of prefix names) and results (with the exception of +** bugs; any that are discovered will be fixed), SOFA is not +** responsible for any errors found in this version of the library. +** +** If you wish to acknowledge the SOFA heritage, please acknowledge +** that you are using a library derived from SOFA, rather than SOFA +** itself. +** +** +** TERMS AND CONDITIONS +** +** Redistribution and use in source and binary forms, with or without +** modification, are permitted provided that the following conditions +** are met: +** +** 1 Redistributions of source code must retain the above copyright +** notice, this list of conditions and the following disclaimer. +** +** 2 Redistributions in binary form must reproduce the above copyright +** notice, this list of conditions and the following disclaimer in +** the documentation and/or other materials provided with the +** distribution. +** +** 3 Neither the name of the Standards Of Fundamental Astronomy Board, +** the International Astronomical Union nor the names of its +** contributors may be used to endorse or promote products derived +** from this software without specific prior written permission. +** +** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS +** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE +** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, +** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, +** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; +** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER +** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN +** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE +** POSSIBILITY OF SUCH DAMAGE. +** +*/ |