Table of contents
CSPICE_ROTMAT calculates the 3x3 rotation matrix generated by
a rotation of a specified angle about a specified axis applied
to a matrix. This rotation is thought of as rotating the
coordinate system.
Given:
m1 a 3x3 matrix to which a rotation is to be applied.
help, m1
DOUBLE = Array[3,3]
In matrix algebra, the components of the matrix are relevant in
one particular coordinate system. Applying cspice_rotmat changes
the components of `m1' so that they are relevant to a rotated
coordinate system.
angle the angle in radians through which the original coordinate
system is to be rotated.
help, angle
DOUBLE = Scalar
iaxis the index for the axis of the original coordinate system about
which the rotation by `angle' is to be performed.
help, iaxis
LONG = Scalar
iaxis = 1,2 or 3 designates the X-, Y- or Z-axis, respectively.
the call:
cspice_rotmat, m1, angle, iaxis, mout
returns:
mout the matrix resulting from the application of the specified
rotation to the input matrix `m1'.
help, mout
DOUBLE = Array[3,3]
If
[angle]
iaxis
denotes the rotation matrix by `angle' radians about `iaxis',
(refer to the routine cspice_rotate) then `mout' is given by
the following matrix equation:
mout = [angle] * m1
iaxis
None.
Any numerical results shown for this example may differ between
platforms as the results depend on the SPICE kernels used as input
and the machine specific arithmetic implementation.
1) Rotate the 3x3 identity matrix by 90 degrees about
the y axis.
Example code begins here.
PRO rotmat_ex1
;;
;; Create the 3x3 identity matrix.
;;
cspice_ident, ident
;;
;; Rotate 'ident' by Pi/2 about the Y axis.
;;
cspice_rotmat, ident, cspice_halfpi(), 2, r
;;
;; Output the resulting matrix.
;;
print, FORMAT='(3F18.12)', r(*,0)
print, FORMAT='(3F18.12)', r(*,1)
print, FORMAT='(3F18.12)', r(*,2)
END
When this program was executed on a Mac/Intel/IDL8.x/64-bit
platform, the output was:
0.000000000000 0.000000000000 -1.000000000000
0.000000000000 1.000000000000 0.000000000000
1.000000000000 0.000000000000 0.000000000000
The call has the effect of:
cspice_rotate, angle, iaxis, r
cspice_mxm, r, m1, mout
1) If the axis index is not in the range 1 to 3, it will be
treated the same as that integer 1, 2, or 3 that is congruent
to it mod 3.
2) If any of the input arguments, `m1', `angle' or `iaxis', is
undefined, an error is signaled by the IDL error handling
system.
3) If any of the input arguments, `m1', `angle' or `iaxis', is
not of the expected type, or it does not have the expected
dimensions and size, an error is signaled by the Icy
interface.
4) If the output argument `mout' is not a named variable, an
error is signaled by the Icy interface.
None.
None.
ICY.REQ
ROTATION.REQ
None.
J. Diaz del Rio (ODC Space)
E.D. Wright (JPL)
-Icy Version 1.0.3, 10-AUG-2021 (JDR)
Edited the -Examples section to comply with NAIF standard. Added
example's problem statement and reformatted example's output.
Added -Parameters, -Exceptions, -Files, -Restrictions,
-Literature_References and -Author_and_Institution sections.
Removed reference to the routine's corresponding CSPICE header from
-Abstract section.
Added arguments' type and size information in the -I/O section.
-Icy Version 1.0.2, 08-JAN-2008 (EDW)
Rewrote the -I/O descriptions. The 1.0.1 version of this file
lacked complete descriptions of the arguments. Included functional
example code.
-Icy Version 1.0.1, 09-DEC-2005 (EDW)
Added -Examples section.
-Icy Version 1.0.0, 16-JUN-2003 (EDW)
rotate a matrix
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