Load real data into x and complex data into y and you will get the results
Fast Fourier Transform How it actually works: Give it an array of complex data It will take every odd index and even index and split into 2 separate groups. It will then take those groups and do this again. It will keep doing this until you have groups of size 2. It does a discrete Fourier transform on these groups. The group of 2 are simple add for first term and subtract for second. Then it does what is often described as the butterfly diagram. You have your circle and divide it up into angles depending on the group size, so a size 4 even + 4 odd arrays is 8 45 degrees. You get the complex coordinates of these angles. You multiply the odd term by the corresponding frequencies, sometimes called a twiddle factor and then add to the corresponding even terms. You then keep doing this until you are at the original size of your data and have your fft. For the inverse, you do the same but you multiply by 1/size and reorder at the end.
