Function halo2_proofs::arithmetic::best_fft

pub fn best_fft<G: Group>(a: &mut [G], omega: G::Scalar, log_n: u32)

Performs a radix-$2$ Fast-Fourier Transformation (FFT) on a vector of size $n = 2^k$, when provided log_n = $k$ and an element of multiplicative order $n$ called omega ($\omega$). The result is that the vector a, when interpreted as the coefficients of a polynomial of degree $n - 1$, is transformed into the evaluations of this polynomial at each of the $n$ distinct powers of $\omega$. This transformation is invertible by providing $\omega^{-1}$ in place of $\omega$ and dividing each resulting field element by $n$.

This will use multithreading if beneficial.