Merge commit '7fde2daeed593684120d75de07598154f3ddaf2c' as 'ast'

1 files changed, 153 insertions, 0 deletions

diff --git a/ast/erfa/pv2s.c b/ast/erfa/pv2s.c
new file mode 100644
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+++ b/ast/erfa/pv2s.c
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+#include "erfa.h"
+
+void eraPv2s(double pv[2][3],
+             double *theta, double *phi, double *r,
+             double *td, double *pd, double *rd)
+/*
+**  - - - - - - - -
+**   e r a P v 2 s
+**  - - - - - - - -
+**
+**  Convert position/velocity from Cartesian to spherical coordinates.
+**
+**  Given:
+**     pv       double[2][3]  pv-vector
+**
+**  Returned:
+**     theta    double        longitude angle (radians)
+**     phi      double        latitude angle (radians)
+**     r        double        radial distance
+**     td       double        rate of change of theta
+**     pd       double        rate of change of phi
+**     rd       double        rate of change of r
+**
+**  Notes:
+**
+**  1) If the position part of pv is null, theta, phi, td and pd
+**     are indeterminate.  This is handled by extrapolating the
+**     position through unit time by using the velocity part of
+**     pv.  This moves the origin without changing the direction
+**     of the velocity component.  If the position and velocity
+**     components of pv are both null, zeroes are returned for all
+**     six results.
+**
+**  2) If the position is a pole, theta, td and pd are indeterminate.
+**     In such cases zeroes are returned for all three.
+**
+**  Copyright (C) 2013-2014, NumFOCUS Foundation.
+**  Derived, with permission, from the SOFA library.  See notes at end of file.
+*/
+{
+   double x, y, z, xd, yd, zd, rxy2, rxy, r2, rtrue, rw, xyp;
+
+
+/* Components of position/velocity vector. */
+   x  = pv[0][0];
+   y  = pv[0][1];
+   z  = pv[0][2];
+   xd = pv[1][0];
+   yd = pv[1][1];
+   zd = pv[1][2];
+
+/* Component of r in XY plane squared. */
+   rxy2 = x*x + y*y;
+
+/* Modulus squared. */
+   r2 = rxy2 + z*z;
+
+/* Modulus. */
+   rtrue = sqrt(r2);
+
+/* If null vector, move the origin along the direction of movement. */
+   rw = rtrue;
+   if (rtrue == 0.0) {
+       x = xd;
+       y = yd;
+       z = zd;
+       rxy2 = x*x + y*y;
+       r2 = rxy2 + z*z;
+       rw = sqrt(r2);
+   }
+
+/* Position and velocity in spherical coordinates. */
+   rxy = sqrt(rxy2);
+   xyp = x*xd + y*yd;
+   if (rxy2 != 0.0) {
+       *theta = atan2(y, x);
+       *phi = atan2(z, rxy);
+       *td = (x*yd - y*xd) / rxy2;
+       *pd = (zd*rxy2 - z*xyp) / (r2*rxy);
+   } else {
+       *theta = 0.0;
+       *phi = (z != 0.0) ? atan2(z, rxy) : 0.0;
+       *td = 0.0;
+       *pd = 0.0;
+   }
+   *r = rtrue;
+   *rd = (rw != 0.0) ? (xyp + z*zd) / rw : 0.0;
+
+   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.
+**  
+*/