Generalization of the fast Fourier transform with a constant structure

The widely popular famous fast Cooley–Tukey algorithms for the discrete Fourier transform of mixed radix are presented in two forms: classical and with a constant structure. A matrix representation of these algorithms is proposed in terms of two types of tensor product of matrices: the Kronecker product and the $b$-product. This matrix representation shows that the structure of these algorithms is identical to two fast Good algorithms for a Kronecker power of a matrix. A technique for constructing matrix-form fast algorithms for the discrete Fourier and Chrestenson transforms with mixed radix and for the discrete Vilenkin transform is demonstrated. It is shown that the constant-structured algorithm is preferable in the case of more sophisticated constructions.