I have a set of N data points defined over a periodic interval, [itex]0\le x \le 1[/itex]. I made a discrete fast fourier transform of these data points and I get a discretized function in the Fuorier space. My question is what are the coordinate of these data points in the Fourier space? I mean, in the real space I have in a point x=3 my function f=7. After my discrete fourier transform I know that this correspond to f'=49 what is the coordinate k? All I know is that when I apply my discrete fourier transform to my data I have a periodic function with period N/2.