Search results
Results from the WOW.Com Content Network
The Cooley–Tukey algorithm, named after J. W. Cooley and John Tukey, is the most common fast Fourier transform (FFT) algorithm. It re-expresses the discrete Fourier transform (DFT) of an arbitrary composite size = in terms of N 1 smaller DFTs of sizes N 2, recursively, to reduce the computation time to O(N log N) for highly composite N (smooth numbers).
The corresponding FFT algorithm would consist of first computing x k (z) = x(z) mod F k (z), then computing x k,j (z) = x k (z) mod F k,j (z), and so on, recursively creating more and more remainder polynomials of smaller and smaller degree until one arrives at the final degree-0 results.
A fast Fourier transform (FFT) is an algorithm that computes the discrete Fourier transform (DFT) of a sequence, or its inverse (IDFT). A Fourier transform converts a signal from its original domain (often time or space) to a representation in the frequency domain and vice versa.
This category is for fast Fourier transform (FFT) algorithms, i.e. algorithms to compute the discrete Fourier transform (DFT) in O(N log N) time (or better, for approximate algorithms), where is the number of discrete points.
The most common multidimensional FFT algorithm is the row-column algorithm, which means transforming the array first in one index and then in the other, see more in FFT. Then a radix-2 direct 2-D FFT has been developed, [ 2 ] and it can eliminate 25% of the multiplies as compared to the conventional row-column approach.
It works by recursively applying fast Fourier transform (FFT) over the integers modulo +. The run-time bit complexity to multiply two n -digit numbers using the algorithm is O ( n ⋅ log n ⋅ log log n ) {\displaystyle O(n\cdot \log n\cdot \log \log n)} in big O notation .
The prime-factor algorithm (PFA), also called the Good–Thomas algorithm (1958/1963), is a fast Fourier transform (FFT) algorithm that re-expresses the discrete Fourier transform (DFT) of a size N = N 1 N 2 as a two-dimensional N 1 ×N 2 DFT, but only for the case where N 1 and N 2 are relatively prime.
The split-radix FFT is a fast Fourier transform (FFT) algorithm for computing the discrete Fourier transform (DFT), and was first described in an initially little-appreciated paper by R. Yavne (1968) and subsequently rediscovered simultaneously by various authors in 1984.