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/*
*+
* Name:
* palDeuler
* Purpose:
* Form a rotation matrix from the Euler angles
* Language:
* Starlink ANSI C
* Type of Module:
* Library routine
* Invocation:
* void palDeuler ( const char *order, double phi, double theta, double psi,
* double rmat[3][3] );
* Arguments:
* order = const char[] (Given)
* Specifies about which axes the rotation occurs
* phi = double (Given)
* 1st rotation (radians)
* theta = double (Given)
* 2nd rotation (radians)
* psi = double (Given)
* 3rd rotation (radians)
* rmat = double[3][3] (Given & Returned)
* Rotation matrix
* Description:
* 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.
* Authors:
* PTW: Pat Wallace (STFC)
* TIMJ: Tim Jenness (JAC, Hawaii)
* {enter_new_authors_here}
* History:
* 2012-02-08 (TIMJ):
* Initial version with documentation taken from Fortran SLA
* Adapted with permission from the Fortran SLALIB library.
* {enter_further_changes_here}
* Copyright:
* Copyright (C) 1997 Rutherford Appleton Laboratory
* Copyright (C) 2012 Science and Technology Facilities Council.
* All Rights Reserved.
* Licence:
* This program is free software: you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation, either
* version 3 of the License, or (at your option) any later
* version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General
* License along with this program. If not, see
* <http://www.gnu.org/licenses/>.
* Bugs:
* {note_any_bugs_here}
*-
*/
#include "pal.h"
#include "pal1sofa.h"
void
palDeuler( const char *order, double phi, double theta, double psi,
double rmat[3][3] ) {
int i = 0;
double rotations[3];
/* Initialise rmat */
eraIr( rmat );
/* copy the rotations into an array */
rotations[0] = phi;
rotations[1] = theta;
rotations[2] = psi;
/* maximum three rotations */
while (i < 3 && order[i] != '\0') {
switch (order[i]) {
case 'X':
case 'x':
case '1':
eraRx( rotations[i], rmat );
break;
case 'Y':
case 'y':
case '2':
eraRy( rotations[i], rmat );
break;
case 'Z':
case 'z':
case '3':
eraRz( rotations[i], rmat );
break;
default:
/* break out the loop if we do not recognize something */
i = 3;
}
/* Go to the next position */
i++;
}
return;
}
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