“…Derivatives [due to Powell (1964), bas&d on conjugate directions], Numerical Derivatives, and Analytic Derivatives [the latter two are quasi-Newton methods, as discussed by Gill, Murray, and Wright (1981) and Hendry, Neale, and Srba (1987)l. For each method, at least some iterations are displayed on a screen that is overwritten with new values of the coefficients.…”