Comments, on "Comparison of the FFT conjugate gradient method and the finite-difference time domain method for the 2-D absorption problem" [with reply]

For the original article see ibid., vol.MTT-35, no.4, p.383-95 (1987). In commenting on the above named work by D.T. Borup et al. it is asserted that certain wrong assumptions about the FFT (fast Fourier transform) conjugate gradient method lead to meaningless statements in the original work. In a reply from two of the three original authors is it made clear that (1) several conclusions attributed to the original work do not appear in the work; and (2) an algorithm claimed in the comment to be the solution of an operator equation, as opposed to a matrix equation, is actually equivalent to a matrix moment solution.<>