How to compute FFT?

Hi there

I just would like to ask, if there is an efficient way to compute the FFT without using the built-in method? Because i need the code on something else, so i found a code to compute it, however, it takes a very long time, so i would highly appreciate it if you could suggest me any way to make it more faster? thank you in advance

function z=Fast_Fourier_Transform(x,nfft)
%
 j=sqrt(-1);
 N=length(x);
 z=zeros(1,nfft);
 Sum=0;
 for k=1:nfft
     for jj=1:N
         Sum=Sum+x(jj)*exp(-2*pi*j*(jj-1)*(k-1)/nfft);
     end
 z(k)=Sum;
 Sum=0;% Reset
 end
 return

Answer 1

[John D'Errico]

Sorry. You are never going to make that code run as fast as FFT, or even reasonably close to it.

You can always look for a C based FFT code. There must be lots of them around.

[Afnan H.]

Thank you for your answer. But could you please clear this for me, so you mean the problem with the code itself? or that i can't implement a code that computes FFT in a fast way using Matlab?