Return crystallographic param. from unit cell lattice matrix.

def lattice_array_to_unit_cell(lattice_array):
    """Return crystallographic param. from unit cell lattice matrix."""
    cell_lengths = np.sqrt(np.sum(lattice_array**2, axis=0))
    gamma_r = np.arccos(lattice_array[0][1] / cell_lengths[1])
    beta_r = np.arccos(lattice_array[0][2] / cell_lengths[2])
    alpha_r = np.arccos(
        lattice_array[1][2] * np.sin(gamma_r) / cell_lengths[2]
        + np.cos(beta_r) * np.cos(gamma_r)
        )
    cell_angles = [
        np.rad2deg(alpha_r), np.rad2deg(beta_r), np.rad2deg(gamma_r)
        ]
    return np.append(cell_lengths, cell_angles)