T2C2000.f90

      SUBROUTINE T2C2000 ( RPOM, THETA, RBPN, RT2C )
!+
!  - - - - - - - -
!   T 2 C 2 0 0 0
!  - - - - - - - -
!
!  Form the TRS-to-CRS matrix, IAU 2000, from components.
!
!  Annex to IERS Conventions 2000, Chapter 5
!
!  Given:
!     RPOM     d(3,3)   polar motion matrix (W)
!
!  followed by either (for the CEO-based transformation):
!     THETA      d      Earth Rotation Angle (radians, giving matrix R)
!     RBPN     d(3,3)   intermediate-to-celestial matrix (Q)
!
!  or alternatively (for the classical, equinox-based, transformation):
!     THETA      d      Greenwich Sidereal Time (radians)
!     RBPN     d(3,3)   true-to-celestial matrix
!
!  Returned:
!     RT2C     d(3,3)   terrestrial-to-celestial matrix
!
!  Calls the SOFA routines iau_CR, iau_RZ, iau_RXR.
!
!  This revision:  2002 November 25
!
!-----------------------------------------------------------------------

      IMPLICIT NONE

      REAL*8 RPOM(3,3), THETA, RBPN(3,3), RT2C(3,3)

      REAL*8 R(3,3)

! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

!  Polar motion.
      CALL iau_CR ( RPOM, R )

!  Earth rotation.
      CALL iau_RZ ( -THETA, R )

!  CIP motion.
      CALL iau_RXR ( RBPN, R, RT2C )

      END