Fast Fourier transform: Difference between revisions

The purpose of this task is to calculate the FFT (Fast Fourier Transform) of an input sequence. The most general case allows for complex numbers at the input and results in a sequence of equal length, again of complex numbers. If you need to restrict yourself to real numbers the output should be the magnitude (i.e. sqrt(re²+im²)) of the complex result. The classic version is the recursive Cooley–Tukey FFT. [http://en.wikipedia.org/wiki/Cooley–Tukey_FFT_algorithm Wikipedia] has pseudocode for that. Further optimizations are possible but not required.