Mike
nlsList from nlme library can fit nonlinear models for dataset grouped by
some specification, e.g. by specie in your case
Regards
Christian
>-- Mensaje Original --
>From: "Mike Saunders" <[EMAIL PROTECTED]>
>To: "R Help" <[EMAIL PROTECTED]>
>Date: Thu, 16 Dec 2004 10:40:00 -0500
>Subject: [R]
Suchandra Thapa <[EMAIL PROTECTED]> writes:
> I'm running into problems trying to use the nls function to fit the some
> data. I'm invoking nls using
>
> nls(s~k/(a+r)^b, start=list(k=1, a=13, b=0.59))
>
> but I get errors indicating that the step has been reduced below the
> minimum step size
An article in the American Statistician perhaps 5 years ago on the
accuracy of statistical software recommended using nlminb first to find
the least squares solution and then pass those numbers to nls to get
confidence intervals. More recently, optim has replaced nlminb for such
purposes, a
