How MATLAB fft processes data which length is not equal to 2^p (p = 1,2,...)

Can someone let me know "How MATLAB fft processes data which length is not equal to 2^p (p = 1,2,...)"?

More specifically if data length = n * 2^7 = n*128, when the length is not one of 2^p (p = 7,8,9, ...).

Thanks

Chen

[Dyuman Joshi]

If I understood your query properly, this should help - More About section of the FFT Documentation

[Chen Wu]

Thank Dyuman

The Tips in the link just tell how to select length of data for FFT. But they donot tell how DFT in matlab be caculated by fft, if data length, say 50*128, i.e. fft(data(50*128,1)).

Answer 1

[Bruno Luong]

MATLAB FFT use FFT in the est library.

The reference here explain the algorithm http://www.fftw.org/fftw-paper-ieee.pdf

[Chen Wu]

Looks this paper can answer my question. However, it needs a lot time to read it.

Thanks for giving me the link.