Example usage of the Discrete Fourier Transform (DFT) functions in Apple's Accelerate framework written in Swift, including a bandpass filter. This is more intendended as an example on how to use both forward and inverse DFT, and how to apply a bandpass filter in between these steps. Evenly sampled values are assumed with an underlying samplerate for the bandpass filter to work. Both phase and magnitudes are calculated and bandpassed, as well as the values themselves.
Tested with Swift 5 and Xcode 12.4.