I always enjoy these direct comparisons between different software packages. I coded this up in AD Model Builder which is freely available at http://admb-project.org ADMB calculates exact derivatives via automatic differentiation so it tends to be more stable for these difficult problems.
The parameter estimates are # Number of parameters = 3 Objective function value = 307873. Maximum gradient component = 1.45914e-06 # NS: 0.00865232633386 # LogKi: -8.98700621813 # BMax: 237135.365156 The objective function is just least squares. So it looks like SAS did pretty well before dying. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
