Compute screw axis from screw matrix.
- screw_matrixarray-like, shape (4, 4)
A screw matrix consists of a cross-product matrix that represents an axis of rotation, a translation, and a row of zeros.
- screw_axisarray, shape (6,)
Screw axis described by 6 values (omega_1, omega_2, omega_3, v_1, v_2, v_3), where the first 3 components are related to rotation and the last 3 components are related to translation.