Fourier Transforming in C

[KitchiRUs]

Hi,

This may not be the ideal place to post this, but what the heck.

I was wondering about Fourier Transform algorithms for C.
I tried writing a code to do a straight forward DFT (Discrete Fourier Transform), not the FFT algorithm. But I'm not entirely sure if it's worked out right.

Has anyone tried it/know what the DFT of a sin wave should look like?

[Wilker]

you are probably right...this may not be the ideal place for this...
might sound a stupid question, but have you tried a numerical methods book? i mean, is very probable they have this topic there. maybe with examples or an elementar case.
would be good if you could test an elementar case (firstly done analitically) and then check how good is your result, calculated numerically.
i have never done the FT algorhitm

[mmix]

https://en.wikipedia.org/wiki/Discre...rier_transform

http://nolandda.org/pusite/cs490-dsp/dft.c.html

http://opencv.itseez.com/doc/tutoria...transform.html

http://www.fftw.org/
http://www.fftw.org/fftw3_doc/Multi_...s-of-Real-Data

http://fftguru.com/

http://www.jjj.de/
http://www.jjj.de/fft/fftpage.html
http://www.jjj.de/fxt/fxtpage.html#fxtbook

[weitjong]

I have done both the FFT and FHT (Fast Hartley Transform) implementation years ago when I was still a university student. I was using Turbo Pascal from Borland back then. If I still remember how it works correctly then you should get two vertical lines if you evaluate from -pi to +pi, both lines at equidistant to each side of zero. But don't hold me to it .

[KitchiRUs]

@ mmix - Thanks! That second link is exactly what I was looking for.
I'd attempted to use the complex number function in C, and I was failing miserably. This guy seems to have done it without that. I still have to run that code to check, though.

@WeitJong - Yeah... I worked it out to be two spikes equidistant from the origin. But I was only getting positive values from my code. So I started doubting my math instead of my code. :P

Thanks for your help!