#include "erfa.h"

void eraFw2m(double gamb, double phib, double psi, double eps,
             double r[3][3])
/*
**  - - - - - - - -
**   e r a F w 2 m
**  - - - - - - - -
**
**  Form rotation matrix given the Fukushima-Williams angles.
**
**  Given:
**     gamb     double         F-W angle gamma_bar (radians)
**     phib     double         F-W angle phi_bar (radians)
**     psi      double         F-W angle psi (radians)
**     eps      double         F-W angle epsilon (radians)
**
**  Returned:
**     r        double[3][3]   rotation matrix
**
**  Notes:
**
**  1) Naming the following points:
**
**           e = J2000.0 ecliptic pole,
**           p = GCRS pole,
**           E = ecliptic pole of date,
**     and   P = CIP,
**
**     the four Fukushima-Williams angles are as follows:
**
**        gamb = gamma = epE
**        phib = phi = pE
**        psi = psi = pEP
**        eps = epsilon = EP
**
**  2) The matrix representing the combined effects of frame bias,
**     precession and nutation is:
**
**        NxPxB = R_1(-eps).R_3(-psi).R_1(phib).R_3(gamb)
**
**  3) The present function can construct three different matrices,
**     depending on which angles are supplied as the arguments gamb,
**     phib, psi and eps:
**
**     o  To obtain the nutation x precession x frame bias matrix,
**        first generate the four precession angles known conventionally
**        as gamma_bar, phi_bar, psi_bar and epsilon_A, then generate
**        the nutation components Dpsi and Depsilon and add them to
**        psi_bar and epsilon_A, and finally call the present function
**        using those four angles as arguments.
**
**     o  To obtain the precession x frame bias matrix, generate the
**        four precession angles and call the present function.
**
**     o  To obtain the frame bias matrix, generate the four precession
**        angles for date J2000.0 and call the present function.
**
**     The nutation-only and precession-only matrices can if necessary
**     be obtained by combining these three appropriately.
**
**  Called:
**     eraIr        initialize r-matrix to identity
**     eraRz        rotate around Z-axis
**     eraRx        rotate around X-axis
**
**  References:
**
**     Capitaine, N. & Wallace, P.T., 2006, Astron.Astrophys. 450, 855
**     Hilton, J. et al., 2006, Celest.Mech.Dyn.Astron. 94, 351
**
**  Copyright (C) 2013-2020, NumFOCUS Foundation.
**  Derived, with permission, from the SOFA library.  See notes at end of file.
*/
{
/* Construct the matrix. */
   eraIr(r);
   eraRz(gamb, r);
   eraRx(phib, r);
   eraRz(-psi, r);
   eraRx(-eps, r);

   return;

}
/*----------------------------------------------------------------------
**  
**  
**  Copyright (C) 2013-2020, 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,
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*/
