There are other multidimensional FFT algorithms that are distinct from the row-column algorithm, although all of them have O("N" log "N") complexity. Perhaps the simplest non-row-column FFT is the vector-radix FFT algorithm, which is a generalization of the ordinary Cooley–Tukey algorithm where one divides the transform dimensions by a vector formula_35 of radices at each step. (This may also have cache benefits.) The simplest case of vector-radix is where all of the radices are equal (e.g. vector-radix-2 divides "all" of the dimensions by two), but this is not necessary. Vector radix with only a single non-unit radix at a time, i.e. formula_36, is essentially a row-column algorithm. Other, more complicated, methods include polynomial transform algorithms due to Nussbaumer (1977), which view the transform in terms of convolutions and polynomial products. See Duhamel and Vetterli (1990) for more information and references.