Davey Taylor

An (I)FFT(R) library - possibly fast/of use to someone

Discussion created by Davey Taylor on Nov 29, 2014
Latest reply on Nov 30, 2014 by Cesar Rabak

Was in need of Q31 in-place IFFT for a Kinetis K20 project with very limited flash and RAM.

While fast implementations I tried were too resource-hungry, low-footprint implementations were just too slow.

 

So I ended up writing this from scratch: stg/SYLT-FFT · GitHub

 

While optimizing and comparing performance with CMSIS DSP I was a bit surprised as performance crept closer and closer.

Eventually I reached break-even, and in it's current state it seems there is an improvement over CMSIS DSP performance.

 

I have only benchmarked fft_inverse and only for N=256 as this was really all I ever needed for my own project.

Using the CMSIS DSP library that comes precompiled with µVision for comparison is perhaps not a good comparison method?

 

Anyone interested in having a look at it, perhaps letting me know how I have failed in my comparison process?

Compiler and library versions, compilation flags, etc. are all documented in the README.md file.

General comments are more than welcome.

Outcomes