#include "sofa.h"

void iauFk52h(double r5, double d5,
              double dr5, double dd5, double px5, double rv5,
              double *rh, double *dh,
              double *drh, double *ddh, double *pxh, double *rvh)
/*
**  - - - - - - - - -
**   i a u F k 5 2 h
**  - - - - - - - - -
**
**  Transform FK5 (J2000.0) star data into the Hipparcos system.
**
**  This function is part of the International Astronomical Union's
**  SOFA (Standards Of Fundamental Astronomy) software collection.
**
**  Status:  support function.
**
**  Given (all FK5, equinox J2000.0, epoch J2000.0):
**     r5      double    RA (radians)
**     d5      double    Dec (radians)
**     dr5     double    proper motion in RA (dRA/dt, rad/Jyear)
**     dd5     double    proper motion in Dec (dDec/dt, rad/Jyear)
**     px5     double    parallax (arcsec)
**     rv5     double    radial velocity (km/s, positive = receding)
**
**  Returned (all Hipparcos, epoch J2000.0):
**     rh      double    RA (radians)
**     dh      double    Dec (radians)
**     drh     double    proper motion in RA (dRA/dt, rad/Jyear)
**     ddh     double    proper motion in Dec (dDec/dt, rad/Jyear)
**     pxh     double    parallax (arcsec)
**     rvh     double    radial velocity (km/s, positive = receding)
**
**  Notes:
**
**  1) This function transforms FK5 star positions and proper motions
**     into the system of the Hipparcos catalog.
**
**  2) The proper motions in RA are dRA/dt rather than
**     cos(Dec)*dRA/dt, and are per year rather than per century.
**
**  3) The FK5 to Hipparcos transformation is modeled as a pure
**     rotation and spin;  zonal errors in the FK5 catalog are not
**     taken into account.
**
**  4) See also iauH2fk5, iauFk5hz, iauHfk5z.
**
**  Called:
**     iauStarpv    star catalog data to space motion pv-vector
**     iauFk5hip    FK5 to Hipparcos rotation and spin
**     iauRxp       product of r-matrix and p-vector
**     iauPxp       vector product of two p-vectors
**     iauPpp       p-vector plus p-vector
**     iauPvstar    space motion pv-vector to star catalog data
**
**  Reference:
**
**     F.Mignard & M.Froeschle, Astron.Astrophys., 354, 732-739 (2000).
**
**  This revision:  2017 October 12
**
**  SOFA release 2020-07-21
**
**  Copyright (C) 2020 IAU SOFA Board.  See notes at end.
*/
{
   int i;
   double pv5[2][3], r5h[3][3], s5h[3], wxp[3], vv[3], pvh[2][3];


/* FK5 barycentric position/velocity pv-vector (normalized). */
   iauStarpv(r5, d5, dr5, dd5, px5, rv5, pv5);

/* FK5 to Hipparcos orientation matrix and spin vector. */
   iauFk5hip(r5h, s5h);

/* Make spin units per day instead of per year. */
   for ( i = 0; i < 3; s5h[i++] /= 365.25 );

/* Orient the FK5 position into the Hipparcos system. */
   iauRxp(r5h, pv5[0], pvh[0]);

/* Apply spin to the position giving an extra space motion component. */
   iauPxp(pv5[0], s5h, wxp);

/* Add this component to the FK5 space motion. */
   iauPpp(wxp, pv5[1], vv);

/* Orient the FK5 space motion into the Hipparcos system. */
   iauRxp(r5h, vv, pvh[1]);

/* Hipparcos pv-vector to spherical. */
   iauPvstar(pvh, rh, dh, drh, ddh, pxh, rvh);

   return;

/*----------------------------------------------------------------------
**
**  Copyright (C) 2020
**  Standards Of Fundamental Astronomy Board
**  of the International Astronomical Union.
**
**  =====================
**  SOFA Software License
**  =====================
**
**  NOTICE TO USER:
**
**  BY USING THIS SOFTWARE YOU ACCEPT THE FOLLOWING SIX TERMS AND
**  CONDITIONS WHICH APPLY TO ITS USE.
**
**  1. The Software is owned by the IAU SOFA Board ("SOFA").
**
**  2. Permission is granted to anyone to use the SOFA software for any
**     purpose, including commercial applications, free of charge and
**     without payment of royalties, subject to the conditions and
**     restrictions listed below.
**
**  3. You (the user) may copy and distribute SOFA source code to others,
**     and use and adapt its code and algorithms in your own software,
**     on a world-wide, royalty-free basis.  That portion of your
**     distribution that does not consist of intact and unchanged copies
**     of SOFA source code files is a "derived work" that must comply
**     with the following requirements:
**
**     a) Your work shall be marked or carry a statement that it
**        (i) uses routines and computations derived by you from
**        software provided by SOFA under license to you; and
**        (ii) does not itself constitute software provided by and/or
**        endorsed by SOFA.
**
**     b) The source code of your derived work must contain descriptions
**        of how the derived work is based upon, contains and/or differs
**        from the original SOFA software.
**
**     c) The names of all routines in your derived work shall not
**        include the prefix "iau" or "sofa" or trivial modifications
**        thereof such as changes of case.
**
**     d) The origin of the SOFA components of your derived work must
**        not be misrepresented;  you must not claim that you wrote the
**        original software, nor file a patent application for SOFA
**        software or algorithms embedded in the SOFA software.
**
**     e) These requirements must be reproduced intact in any source
**        distribution and shall apply to anyone to whom you have
**        granted a further right to modify the source code of your
**        derived work.
**
**     Note that, as originally distributed, the SOFA software is
**     intended to be a definitive implementation of the IAU standards,
**     and consequently third-party modifications are discouraged.  All
**     variations, no matter how minor, must be explicitly marked as
**     such, as explained above.
**
**  4. You shall not cause the SOFA software to be brought into
**     disrepute, either by misuse, or use for inappropriate tasks, or
**     by inappropriate modification.
**
**  5. The SOFA software is provided "as is" and SOFA makes no warranty
**     as to its use or performance.   SOFA does not and cannot warrant
**     the performance or results which the user may obtain by using the
**     SOFA software.  SOFA makes no warranties, express or implied, as
**     to non-infringement of third party rights, merchantability, or
**     fitness for any particular purpose.  In no event will SOFA be
**     liable to the user for any consequential, incidental, or special
**     damages, including any lost profits or lost savings, even if a
**     SOFA representative has been advised of such damages, or for any
**     claim by any third party.
**
**  6. The provision of any version of the SOFA software under the terms
**     and conditions specified herein does not imply that future
**     versions will also be made available under the same terms and
**     conditions.
*
**  In any published work or commercial product which uses the SOFA
**  software directly, acknowledgement (see www.iausofa.org) is
**  appreciated.
**
**  Correspondence concerning SOFA software should be addressed as
**  follows:
**
**      By email:  sofa@ukho.gov.uk
**      By post:   IAU SOFA Center
**                 HM Nautical Almanac Office
**                 UK Hydrographic Office
**                 Admiralty Way, Taunton
**                 Somerset, TA1 2DN
**                 United Kingdom
**
**--------------------------------------------------------------------*/
}
