Cooley-Tukey 1965: DFT in O(n log n) via divide-and-conquer. Bluestein, Rader for non-power-of-two. Convolution theorem → O(n log n) multiplication.
Cooley-Tukey 1965: DFT in O(n log n) via divide-and-conquer. Bluestein, Rader for non-power-of-two. Convolution theorem → O(n log n) multiplication.