Ref comment https://news.ycombinator.com/item?id=25195046 https://news.ycombinator.com/item?id=25195046 about this. Further to that, if you replace x with comp

Ref comment https://news.ycombinator.com/item?id=25195046 https://news.ycombinator.com/item?id=25195046 about this. Further to that, if you replace x with complex variable z^-1, you get what is usually called the z-transform. Set z to a specific complex root of unity exp(i2pi/N) and you have your discrete FT. One of the algorithms for multiplying large arbitrary precision numbers uses multiplication of the discrete transform of the digit sequences (in a different base) iirc. Same thing.