FFT speed problem in C Coder

Dear all,

I used Matlab Coder to convert a function containing FFT into C code.

But it is very slow.

I've checked some of the C code.

It looks like the FFT operation is not optimized.

I inquire if I can use FFTW or MKL. (I don't know in which menu of the coder app these functions are available.)

I can use both Matlab C Coder and Embedded Coder.

I need help with this issue.

Answer 1

[Jongmin Kim]

I looked at the code generated by the coder.

• fft.h/fft.c
• FFTImplementationCallback.h/FFTImplementationCallback.c

Do I have to edit this file myself?

Answer 2

[Raghu Boggavarapu]

If you have generated MEX code, generated code will by default have calls to FFTW library. However, if you are generating standalone code, code generator will produce code for FFT algorithms. If you have a FFTW library installed, please follow the instructions in the page Abstract class for specifying an FFTW library for FFTW calls in generated code - MATLAB (mathworks.com) to integrate the Library with MATLAB Coder generated code.