#include "erfa.h"

void eraPom00(double xp, double yp, double sp, double rpom[3][3])
/*
**  - - - - - - - - - -
**   e r a P o m 0 0
**  - - - - - - - - - -
**
**  Form the matrix of polar motion for a given date, IAU 2000.
**
**  Given:
**     xp,yp    double    coordinates of the pole (radians, Note 1)
**     sp       double    the TIO locator s' (radians, Note 2)
**
**  Returned:
**     rpom     double[3][3]   polar-motion matrix (Note 3)
**
**  Notes:
**
**  1) The arguments xp and yp are the coordinates (in radians) of the
**     Celestial Intermediate Pole with respect to the International
**     Terrestrial Reference System (see IERS Conventions 2003),
**     measured along the meridians to 0 and 90 deg west respectively.
**
**  2) The argument sp is the TIO locator s', in radians, which
**     positions the Terrestrial Intermediate Origin on the equator.  It
**     is obtained from polar motion observations by numerical
**     integration, and so is in essence unpredictable.  However, it is
**     dominated by a secular drift of about 47 microarcseconds per
**     century, and so can be taken into account by using s' = -47*t,
**     where t is centuries since J2000.0.  The function eraSp00
**     implements this approximation.
**
**  3) The matrix operates in the sense V(TRS) = rpom * V(CIP), meaning
**     that it is the final rotation when computing the pointing
**     direction to a celestial source.
**
**  Called:
**     eraIr        initialize r-matrix to identity
**     eraRz        rotate around Z-axis
**     eraRy        rotate around Y-axis
**     eraRx        rotate around X-axis
**
**  Reference:
**
**     McCarthy, D. D., Petit, G. (eds.), IERS Conventions (2003),
**     IERS Technical Note No. 32, BKG (2004)
**
**  Copyright (C) 2013-2017, NumFOCUS Foundation.
**  Derived, with permission, from the SOFA library.  See notes at end of file.
*/
{

/* Construct the matrix. */
   eraIr(rpom);
   eraRz(sp, rpom);
   eraRy(-xp, rpom);
   eraRx(-yp, rpom);

   return;

}
/*----------------------------------------------------------------------
**  
**  
**  Copyright (C) 2013-2017, 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
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**  FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
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*/