Example Usage of the Fourier-Transform using Apple's Accelerate Framework in Swift, including a Bandpass Filter. This is more intendended as an example on how to use both forward and backward FFT, and how to apply a bandpass filter inbetween these steps. Evenly sampled values are assumed with an underlying framerate (i.e. FPS) for the bandpass filter to work. Both phase and magnitudes are calculated and bandpassed, as well as the values themselves.
Tested with Swift 3 and Xcode 8.3.1.