An APL program for bilinear transformations

An efficient APL [1], [2] computer program is presented for the calculation of the bilinear transformations
Z = (S + 1)/(S - 1)
or
S = (Z + 1)/(Z - 1)
using the
Q
-matrix of Fielder [6]. The program utilizes the extremely efficient matrix manipulation and computational properties afforded by the APL language.