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SUBROUTINE sla_EULER (ORDER, PHI, THETA, PSI, RMAT)
*+
* - - - - - -
* E U L E R
* - - - - - -
*
* Form a rotation matrix from the Euler angles - three successive
* rotations about specified Cartesian axes (single precision)
*
* Given:
* ORDER c*(*) specifies about which axes the rotations occur
* PHI r 1st rotation (radians)
* THETA r 2nd rotation ( " )
* PSI r 3rd rotation ( " )
*
* Returned:
* RMAT r(3,3) rotation matrix
*
* A rotation is positive when the reference frame rotates
* anticlockwise as seen looking towards the origin from the
* positive region of the specified axis.
*
* The characters of ORDER define which axes the three successive
* rotations are about. A typical value is 'ZXZ', indicating that
* RMAT is to become the direction cosine matrix corresponding to
* rotations of the reference frame through PHI radians about the
* old Z-axis, followed by THETA radians about the resulting X-axis,
* then PSI radians about the resulting Z-axis.
*
* The axis names can be any of the following, in any order or
* combination: X, Y, Z, uppercase or lowercase, 1, 2, 3. Normal
* axis labelling/numbering conventions apply; the xyz (=123)
* triad is right-handed. Thus, the 'ZXZ' example given above
* could be written 'zxz' or '313' (or even 'ZxZ' or '3xZ'). ORDER
* is terminated by length or by the first unrecognized character.
*
* Fewer than three rotations are acceptable, in which case the later
* angle arguments are ignored. If all rotations are zero, the
* identity matrix is produced.
*
* Called: sla_DEULER
*
* P.T.Wallace Starlink 23 May 1997
*
* Copyright (C) 1997 Rutherford Appleton Laboratory
*-
IMPLICIT NONE
CHARACTER*(*) ORDER
REAL PHI,THETA,PSI,RMAT(3,3)
INTEGER J,I
DOUBLE PRECISION W(3,3)
* Compute matrix in double precision
CALL sla_DEULER(ORDER,DBLE(PHI),DBLE(THETA),DBLE(PSI),W)
* Copy the result
DO J=1,3
DO I=1,3
RMAT(I,J) = REAL(W(I,J))
END DO
END DO
END
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