From a rotation matrix, determine the corresponding axial vector. (double precision) A rotation matrix describes a rotation about some arbitrary axis. The axis is called the Euler axis, and the angle through which the reference frame rotates is called the Euler angle. The axial vector returned by this routine has the same direction as the Euler axis, and its magnitude is the Euler angle in radians. (The magnitude and direction can be separated by means of the routine slaDvn.)
rmat double[3][3] rotation matrix
axvec double[3] axial vector (radians) The reference frame rotates clockwise as seen looking along the axial vector from the origin. If rmat is null, so is the result. P.T.Wallace Starlink 31 October 1993