FFTW is fastest when it has small prime factors according to its manual. If there is the option to pad the input data, then with radix 2 FFT algorithms this is done with a “next power of 2” type function. However if the length is just over a power of 2, at large sizes this can lead to arrays of al…

Optimal Power of N for FFTW

rafael.guerra August 3, 2022, 4:06pm 8

Linking related thread.

1 Like

Topic		Replies	Views
The prevprime and nextprime functions New to Julia question	7	1843	June 10, 2017
Fastest Julia implementation for a cyclic convolution of real vectors Performance fftw , fft	17	387	December 12, 2024
Parallel FFT not that much faster General Usage fftw , parallel , multithreading	10	6992	December 19, 2016
Computing a pruned FFT in O(n*log(k)) Numerics fftw	5	756	November 6, 2022
Is it time to make a pure Julia FFT? Signal and Image Processing fft	14	2820	May 8, 2024