HDINLINE float_X operator()(const float_X N, const float_X omega, const vec1 observer_unit_vec) const
{
/* Form Factor for CIC charge distribution of N discrete electrons:
* | \mathcal{F} |^2 = N + (N*N - N) * sinc^2(n_x * L_x * \omega) * sinc^2(n_y * L_y * \omega) * sinc^2(n_z * L_z * \omega)
*
* with observation direction (unit vector) \vec{n} = (n_x, n_y, n_z)
* and with: N = weighting
* omega = frequency
* L_d = the size of the CIC-particle / cell in dimension d
*
* the Form Factor: sqrt( | \mathcal{F} |^2 ) will be returned
*/
return sqrt(N + (N*N - N) * util::square(
math::sinc( observer_unit_vec.x() * CELL_WIDTH/(SPEED_OF_LIGHT*2) * omega) *
math::sinc( observer_unit_vec.y() * CELL_HEIGHT/(SPEED_OF_LIGHT*2) * omega) *
math::sinc( observer_unit_vec.z() * CELL_DEPTH/(SPEED_OF_LIGHT*2) * omega)
)
);
}
