 In 1994, Gilbert Strang described the FFT as "the most important numerical algorithm of our lifetime", and it was included in Top 10 Algorithms of 20th Century by the IEEE magazine "Computing in Science & Engineering".The best-known FFT algorithms depend upon the factorization of "N", but there are FFTs with O("N" log "N") complexity for all "N", even for prime "N".Many FFT algorithms only depend on the fact that formula_4 is an "N"-th primitive root of unity, and thus can be applied to analogous transforms over any finite field, such as number-theoretic transforms.