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86 lines
2.8 KiB
Fortran
86 lines
2.8 KiB
Fortran
SUBROUTINE sla_EULER (ORDER, PHI, THETA, PSI, RMAT)
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*+
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* - - - - - -
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* E U L E R
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* - - - - - -
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*
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* Form a rotation matrix from the Euler angles - three successive
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* rotations about specified Cartesian axes (single precision)
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*
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* Given:
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* ORDER c*(*) specifies about which axes the rotations occur
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* PHI r 1st rotation (radians)
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* THETA r 2nd rotation ( " )
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* PSI r 3rd rotation ( " )
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*
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* Returned:
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* RMAT r(3,3) rotation matrix
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*
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* A rotation is positive when the reference frame rotates
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* anticlockwise as seen looking towards the origin from the
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* positive region of the specified axis.
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*
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* The characters of ORDER define which axes the three successive
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* rotations are about. A typical value is 'ZXZ', indicating that
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* RMAT is to become the direction cosine matrix corresponding to
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* rotations of the reference frame through PHI radians about the
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* old Z-axis, followed by THETA radians about the resulting X-axis,
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* then PSI radians about the resulting Z-axis.
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*
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* The axis names can be any of the following, in any order or
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* combination: X, Y, Z, uppercase or lowercase, 1, 2, 3. Normal
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* axis labelling/numbering conventions apply; the xyz (=123)
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* triad is right-handed. Thus, the 'ZXZ' example given above
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* could be written 'zxz' or '313' (or even 'ZxZ' or '3xZ'). ORDER
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* is terminated by length or by the first unrecognized character.
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*
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* Fewer than three rotations are acceptable, in which case the later
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* angle arguments are ignored. If all rotations are zero, the
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* identity matrix is produced.
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*
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* Called: sla_DEULER
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*
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* P.T.Wallace Starlink 23 May 1997
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*
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* Copyright (C) 1997 Rutherford Appleton Laboratory
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*
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* License:
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program (see SLA_CONDITIONS); if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place, Suite 330,
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* Boston, MA 02111-1307 USA
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*
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*-
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IMPLICIT NONE
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CHARACTER*(*) ORDER
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REAL PHI,THETA,PSI,RMAT(3,3)
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INTEGER J,I
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DOUBLE PRECISION W(3,3)
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* Compute matrix in double precision
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CALL sla_DEULER(ORDER,DBLE(PHI),DBLE(THETA),DBLE(PSI),W)
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* Copy the result
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DO J=1,3
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DO I=1,3
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RMAT(I,J) = REAL(W(I,J))
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END DO
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END DO
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END
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