about FFT

i’ll keep that post between us members.
My son is entering a preparation school for engineers and they learn Python.
So i thought i’ll give it a go to Pythonista.
After 2 hours of work, being a complete noob in python, i managed to compute / plot an FFT of lena image on my ipad. I guess i’m gone give up my project to write it in Codea/lua…

perhaps here :