I'm trying to write the code for performing nonlinear three-stage least squares and I'm stuck. I need to compute matricies of partial derivatives of residuals with respect to the parameters, etc and I'm having a little trouble getting started. Is there a package that demonstrates computing the jacobian matrix, partial derivatives, etc? Thanks, Jeff. -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._