Further comments on "Design of piecewise constant gains for optimal control via Walsh functions"

Chen and Hsalo, describing a control problem via Walsh functions, include an algorithm to compute a coefficient matrix which involves inverting matrices of order depending on , the number of Walsh functions used. Actually, only two matrices need be inverted for any . The coefficient matrix, the product of a matrix and the Walsh matrix , converts the Walsh expansion into a block pulse function [1] expansion; the transition matrix is simply related to a single precomputed matrix.