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Diffstat (limited to 'ast/erfa/numat.c')
-rw-r--r-- | ast/erfa/numat.c | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/ast/erfa/numat.c b/ast/erfa/numat.c new file mode 100644 index 0000000..6023271 --- /dev/null +++ b/ast/erfa/numat.c @@ -0,0 +1,118 @@ +#include "erfa.h" + +void eraNumat(double epsa, double dpsi, double deps, double rmatn[3][3]) +/* +** - - - - - - - - - +** e r a N u m a t +** - - - - - - - - - +** +** Form the matrix of nutation. +** +** Given: +** epsa double mean obliquity of date (Note 1) +** dpsi,deps double nutation (Note 2) +** +** Returned: +** rmatn double[3][3] nutation matrix (Note 3) +** +** Notes: +** +** +** 1) The supplied mean obliquity epsa, must be consistent with the +** precession-nutation models from which dpsi and deps were obtained. +** +** 2) The caller is responsible for providing the nutation components; +** they are in longitude and obliquity, in radians and are with +** respect to the equinox and ecliptic of date. +** +** 3) The matrix operates in the sense V(true) = rmatn * V(mean), +** where the p-vector V(true) is with respect to the true +** equatorial triad of date and the p-vector V(mean) is with +** respect to the mean equatorial triad of date. +** +** Called: +** eraIr initialize r-matrix to identity +** eraRx rotate around X-axis +** eraRz rotate around Z-axis +** +** Reference: +** +** Explanatory Supplement to the Astronomical Almanac, +** P. Kenneth Seidelmann (ed), University Science Books (1992), +** Section 3.222-3 (p114). +** +** Copyright (C) 2013-2014, NumFOCUS Foundation. +** Derived, with permission, from the SOFA library. See notes at end of file. +*/ +{ +/* Build the rotation matrix. */ + eraIr(rmatn); + eraRx(epsa, rmatn); + eraRz(-dpsi, rmatn); + eraRx(-(epsa + deps), rmatn); + + return; + +} +/*---------------------------------------------------------------------- +** +** +** Copyright (C) 2013-2014, 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. +** +*/ |