directionsDrivenControl.directions Returns the Bloch sphere rotation directions. Returns The Bloch sphere rotation direction on each segment, {vn/∣vn∣}\{\mathbf v_n/|\mathbf v_n|\}{vn/∣vn∣}, where vn=(Ωncosϕn,Ωnsinϕn,Δn)\mathbf v_n=(\Omega_n\cos\phi_n, \Omega_n\sin\phi_n, \Delta_n)vn=(Ωncosϕn,Ωnsinϕn,Δn). Return type np.ndarray