optim() needs starting values too, but *may* be more robust than nls to their specification ....
On Fri, 24 Oct 2003, Giovanni Caggiano wrote: > I am trying to fit to the data a nonlinear function, say z(tau;b) where tau > is the independent variable and b is 3x1 vector of parameters. Following > previous suggestions from the list, I am trying to find some "optimal" > starting values for the three parameters by using the command 'optim' and > then feed these values to nls for estimation. Does anybody know hot to use > 'optim' for this purpose? -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help
