2.3.6 Fast Fourier transform FFT In 1965. cooley and tukey published an algorithm for the computation of the discrete Fourier transform that is applicable when N is a composite number; i. e, N is the product of two or more integers. The algorithms are known as fast Fourier transform, or simply FFt algorithmsIn 1965, Cooley and Tukey published an algorithm for the computation of the discrete Fourier transform that is applicable when N is a composite number; i.e., N is the product of two or more integers. The algorithms are known as fast Fourier transform, or simply FFT, algorithms. 2.3.6 Fast Fourier transform (FFT)