update ast 8.6.3

1 files changed, 161 insertions, 0 deletions

diff --git a/ast/erfa/ld.c b/ast/erfa/ld.c
new file mode 100644
index 0000000..c1569fd
--- /dev/null
+++ b/ast/erfa/ld.c
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+#include "erfa.h"
+
+void eraLd(double bm, double p[3], double q[3], double e[3],
+           double em, double dlim, double p1[3])
+/*
+**  - - - - - -
+**   e r a L d
+**  - - - - - -
+**
+**  Apply light deflection by a solar-system body, as part of
+**  transforming coordinate direction into natural direction.
+**
+**  Given:
+**     bm     double     mass of the gravitating body (solar masses)
+**     p      double[3]  direction from observer to source (unit vector)
+**     q      double[3]  direction from body to source (unit vector)
+**     e      double[3]  direction from body to observer (unit vector)
+**     em     double     distance from body to observer (au)
+**     dlim   double     deflection limiter (Note 4)
+**
+**  Returned:
+**     p1     double[3]  observer to deflected source (unit vector)
+**
+**  Notes:
+**
+**  1) The algorithm is based on Expr. (70) in Klioner (2003) and
+**     Expr. (7.63) in the Explanatory Supplement (Urban & Seidelmann
+**     2013), with some rearrangement to minimize the effects of machine
+**     precision.
+**
+**  2) The mass parameter bm can, as required, be adjusted in order to
+**     allow for such effects as quadrupole field.
+**
+**  3) The barycentric position of the deflecting body should ideally
+**     correspond to the time of closest approach of the light ray to
+**     the body.
+**
+**  4) The deflection limiter parameter dlim is phi^2/2, where phi is
+**     the angular separation (in radians) between source and body at
+**     which limiting is applied.  As phi shrinks below the chosen
+**     threshold, the deflection is artificially reduced, reaching zero
+**     for phi = 0.
+**
+**  5) The returned vector p1 is not normalized, but the consequential
+**     departure from unit magnitude is always negligible.
+**
+**  6) The arguments p and p1 can be the same array.
+**
+**  7) To accumulate total light deflection taking into account the
+**     contributions from several bodies, call the present function for
+**     each body in succession, in decreasing order of distance from the
+**     observer.
+**
+**  8) For efficiency, validation is omitted.  The supplied vectors must
+**     be of unit magnitude, and the deflection limiter non-zero and
+**     positive.
+**
+**  References:
+**
+**     Urban, S. & Seidelmann, P. K. (eds), Explanatory Supplement to
+**     the Astronomical Almanac, 3rd ed., University Science Books
+**     (2013).
+**
+**     Klioner, Sergei A., "A practical relativistic model for micro-
+**     arcsecond astrometry in space", Astr. J. 125, 1580-1597 (2003).
+**
+**  Called:
+**     eraPdp       scalar product of two p-vectors
+**     eraPxp       vector product of two p-vectors
+**
+**  Copyright (C) 2013-2016, NumFOCUS Foundation.
+**  Derived, with permission, from the SOFA library.  See notes at end of file.
+*/
+{
+   int i;
+   double qpe[3], qdqpe, w, eq[3], peq[3];
+
+
+/* q . (q + e). */
+   for (i = 0; i < 3; i++) {
+      qpe[i] = q[i] + e[i];
+   }
+   qdqpe = eraPdp(q, qpe);
+
+/* 2 x G x bm / ( em x c^2 x ( q . (q + e) ) ). */
+   w = bm * ERFA_SRS / em / ERFA_GMAX(qdqpe,dlim);
+
+/* p x (e x q). */
+   eraPxp(e, q, eq);
+   eraPxp(p, eq, peq);
+
+/* Apply the deflection. */
+   for (i = 0; i < 3; i++) {
+      p1[i] = p[i] + w*peq[i];
+   }
+
+/* Finished. */
+
+}
+/*----------------------------------------------------------------------
+**  
+**  
+**  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.
+**  
+*/