SUBROUTINE iau_FW2XY ( GAMB, PHIB, PSI, EPS, X, Y )
*+
*  - - - - - - - - - -
*   i a u _ F W 2 X Y
*  - - - - - - - - - -
*
*  CIP X,Y given Fukushima-Williams bias-precession-nutation angles.
*
*  This routine is part of the International Astronomical Union's
*  SOFA (Standards of Fundamental Astronomy) software collection.
*
*  Status:  support routine.
*
*  Given:
*     GAMB       d      F-W angle gamma_bar (radians)
*     PHIB       d      F-W angle phi_bar (radians)
*     PSI        d      F-W angle psi (radians)
*     EPS        d      F-W angle epsilon (radians)
*
*  Returned:
*     X,Y        d      CIP X,Y ("radians")
*
*  Notes:
*
*  1) Naming the following points:
*
*           e = J2000 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(-EPSA).R_3(-PSI).R_1(PHIB).R_3(GAMB)
*
*     X,Y are elements (3,1) and (3,2) of the matrix.
*
*  Called:
*     iau_FW2M     F-W angles to r-matrix
*     iau_BPN2XY   extract CIP X,Y coordinates from NPB matrix
*
*  Reference:
*
*     Hilton, J. et al., 2006, Celest.Mech.Dyn.Astron. 94, 351
*
*  This revision:   2007 May 9
*
*  Copyright P.T.Wallace.  All rights reserved.
*-

      IMPLICIT NONE

      DOUBLE PRECISION GAMB, PHIB, PSI, EPS, X, Y

      DOUBLE PRECISION R(3,3)


*  Form NxPxB matrix.
      CALL iau_FW2M ( GAMB, PHIB, PSI, EPS, R )

*  Extract CIP X,Y.
      CALL iau_BPN2XY ( R, X, Y )

*  Finished.

*+----------------------------------------------------------------------
*
*  Copyright (C) 2007
*  Standards Of Fundamental Astronomy Review Board
*  of the International Astronomical Union.
*
*  =====================
*  SOFA Software License
*  =====================
*
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*
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*
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*
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*
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*
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*
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*
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*-----------------------------------------------------------------------

      END