update ast 8.6.2

1 files changed, 208 insertions, 0 deletions

diff --git a/ast/erfa/gc2gde.c b/ast/erfa/gc2gde.c
new file mode 100644
index 0000000..43ed61d
--- /dev/null
+++ b/ast/erfa/gc2gde.c
@@ -0,0 +1,208 @@
+#include "erfa.h"
+
+int eraGc2gde ( double a, double f, double xyz[3],
+                double *elong, double *phi, double *height )
+/*
+**  - - - - - - - - - -
+**   e r a G c 2 g d e
+**  - - - - - - - - - -
+**
+**  Transform geocentric coordinates to geodetic for a reference
+**  ellipsoid of specified form.
+**
+**  Given:
+**     a       double     equatorial radius (Notes 2,4)
+**     f       double     flattening (Note 3)
+**     xyz     double[3]  geocentric vector (Note 4)
+**
+**  Returned:
+**     elong   double     longitude (radians, east +ve)
+**     phi     double     latitude (geodetic, radians)
+**     height  double     height above ellipsoid (geodetic, Note 4)
+**
+**  Returned (function value):
+**             int        status:  0 = OK
+**                                -1 = illegal f
+**                                -2 = illegal a
+**
+**  Notes:
+**
+**  1) This function is based on the GCONV2H Fortran subroutine by
+**     Toshio Fukushima (see reference).
+**
+**  2) The equatorial radius, a, can be in any units, but meters is
+**     the conventional choice.
+**
+**  3) The flattening, f, is (for the Earth) a value around 0.00335,
+**     i.e. around 1/298.
+**
+**  4) The equatorial radius, a, and the geocentric vector, xyz,
+**     must be given in the same units, and determine the units of
+**     the returned height, height.
+**
+**  5) If an error occurs (status < 0), elong, phi and height are
+**     unchanged.
+**
+**  6) The inverse transformation is performed in the function
+**     eraGd2gce.
+**
+**  7) The transformation for a standard ellipsoid (such as ERFA_WGS84) can
+**     more conveniently be performed by calling eraGc2gd, which uses a
+**     numerical code to identify the required A and F values.
+**
+**  Reference:
+**
+**     Fukushima, T., "Transformation from Cartesian to geodetic
+**     coordinates accelerated by Halley's method", J.Geodesy (2006)
+**     79: 689-693
+**
+**  Copyright (C) 2013-2016, NumFOCUS Foundation.
+**  Derived, with permission, from the SOFA library.  See notes at end of file.
+*/
+{
+   double aeps2, e2, e4t, ec2, ec, b, x, y, z, p2, absz, p, s0, pn, zc,
+                 c0, c02, c03, s02, s03, a02, a0, a03, d0, f0, b0, s1,
+                 cc, s12, cc2;
+
+
+/* ------------- */
+/* Preliminaries */
+/* ------------- */
+
+/* Validate ellipsoid parameters. */
+   if ( f < 0.0 || f >= 1.0 ) return -1;
+   if ( a <= 0.0 ) return -2;
+
+/* Functions of ellipsoid parameters (with further validation of f). */
+   aeps2 = a*a * 1e-32;
+   e2 = (2.0 - f) * f;
+   e4t = e2*e2 * 1.5;
+   ec2 = 1.0 - e2;
+   if ( ec2 <= 0.0 ) return -1;
+   ec = sqrt(ec2);
+   b = a * ec;
+
+/* Cartesian components. */
+   x = xyz[0];
+   y = xyz[1];
+   z = xyz[2];
+
+/* Distance from polar axis squared. */
+   p2 = x*x + y*y;
+
+/* Longitude. */
+   *elong = p2 > 0.0 ? atan2(y, x) : 0.0;
+
+/* Unsigned z-coordinate. */
+   absz = fabs(z);
+
+/* Proceed unless polar case. */
+   if ( p2 > aeps2 ) {
+
+   /* Distance from polar axis. */
+      p = sqrt(p2);
+
+   /* Normalization. */
+      s0 = absz / a;
+      pn = p / a;
+      zc = ec * s0;
+
+   /* Prepare Newton correction factors. */
+      c0 = ec * pn;
+      c02 = c0 * c0;
+      c03 = c02 * c0;
+      s02 = s0 * s0;
+      s03 = s02 * s0;
+      a02 = c02 + s02;
+      a0 = sqrt(a02);
+      a03 = a02 * a0;
+      d0 = zc*a03 + e2*s03;
+      f0 = pn*a03 - e2*c03;
+
+   /* Prepare Halley correction factor. */
+      b0 = e4t * s02 * c02 * pn * (a0 - ec);
+      s1 = d0*f0 - b0*s0;
+      cc = ec * (f0*f0 - b0*c0);
+
+   /* Evaluate latitude and height. */
+      *phi = atan(s1/cc);
+      s12 = s1 * s1;
+      cc2 = cc * cc;
+      *height = (p*cc + absz*s1 - a * sqrt(ec2*s12 + cc2)) /
+                                                        sqrt(s12 + cc2);
+   } else {
+
+   /* Exception: pole. */
+      *phi = ERFA_DPI / 2.0;
+      *height = absz - b;
+   }
+
+/* Restore sign of latitude. */
+   if ( z < 0 ) *phi = -*phi;
+
+/* OK status. */
+   return 0;
+
+}
+/*----------------------------------------------------------------------
+**  
+**  
+**  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.
+**  
+*/