Function cfo_coefficient 

pub fn cfo_coefficient(n: usize, d: isize, eps: f64) -> C64

The weight $c_{d}$ with which, under a frequency offset eps (in subcarrier spacings), the symbol of the subcarrier $d$ positions away reaches a subcarrier after the DFT of $N$ = n points (Armstrong 1999, eq. (8); Moose 1994, eq. (8)):

$$ c_{d} = \frac{\sin \pi(d + \varepsilon)}{N \sin(\pi(d + \varepsilon)/N)}, e^{j\pi(N - 1)(d + \varepsilon)/N}, $$

comnum_math::diric times its phase; $c_{0}$ is the attenuation and rotation of the wanted symbol, and the others the interference.