Di is a scaling matrix, with ones on the diagonal, except for one entry that scales the ith diagonal element of H to be one. [0123] The transforms x(*vars)=Ay(*vars) and y(*vars)=A???1x(*vars) may be restated in a form similar to Relation 13 by use of the expansion of A: x(*vars)=((F 1 D 1)(F 2 D 2) . . . (F N D N))y(*vars)???(15) y(*vars)=((D N ???1 F N ???1)(D N???1 ???1 F N???1 ???1) . . . (D 1