quat2anax.m

Converts a quaternion representation of a rotation into angle-axis rotation parameters.

Syntax

    [rot_axis,rot_angle]=quat2anax(q)

Arguments

    q   -   quaternion, a structure with four fields
            q.u, q.i, q.j, q.k giving the four compo-
            nents of the quaternion

Outputs

    rot_axis  - cartesian direction vector as a row 
                with three real elements

    rot_angle - rotation angle in radians

Notes

See the notes on rotation conventions for the basic definitions of rotations in Spinach.

See also

euler2dcm.m, wigner.m, quat2dcm.m, dcm2quat.m, anax2quat.m

Version 2.3, authors: Ilya Kuprov