[Rd] extracting and manipulating components from nlme and gnls objects

[Douglas Bates]

On 7/19/05, Nicholas Lewin-Koh <nikko at hailmail.net> wrote:
> Hello,
> I am writing a set of functions to do prediction and calibration
> intervals
> for at least the subset of selfstarting models if not some more general
> ones.
> 
> I need to be able to extract the varFunction from a fit object
> and evaluate it at a predicted point. Are there any examples around?
> 
> Also in a self start model, say SSlogis, how would I get the gradient
> at a point?

I think that the output of 

example(SSlogis)

should answer that question for you.