Discrete Fourier transform

Naive DFT vs. hand-rolled radix-2 FFT vs. numpy.fft.

O(n^2) vs. O(n log n): naive DFT vs. radix-2 FFT vs. numpy.fft

O(n^2) vs. O(n log n): naive DFT vs. radix-2 FFT vs. numpy.fft