Some notes on 2D real-to-complex Fourier transforms

Mon, 15 Jul 2024 20:00:00 +0800

IPP in particular has some very niche ways of packing R2C DFT output, but otherwise there’s a few pointers here to keep in mind for how they are implemented in most libraries.

It’s pretty well known that the output of a Fourier transform of real inputs has symmetric properties. This is due to the fact that real waves consist of two conjugate pairs of complex exponentials.

What may be a bit less obvious (at least to me, when examining some programming libraries) is exactly how many useful output elements there are, and under which scenarios. In particular, I looked at IPP (which has some special packed structure), and cuFFT/NumPy/SciPy (which follow the FFTW structure I think).

Getting IPP to work on non-Intel chips

Mon, 19 Feb 2024 20:00:00 +0800

Intel Performance Primitives is not guaranteed to work on non-Intel chips, but there are some ways around it..

Over the last year or so I’ve written a C++ wrapper of header-only templates around a library known as Intel Performance Primitives (IPP). I often use this for its signal processing library, which is - at least by my measurements - one of the fastest, if not the fastest one around. It also has the benefit of having almost everything I need in one place: FFT/DFTs, math array processing, low-pass filtering etc. You can see my templates at the ipp_ext repository.

Ipp on icyveins7's blog

Some notes on 2D real-to-complex Fourier transforms

Getting IPP to work on non-Intel chips