[R] help with nls and Hill equation
ggrothendieck at gmail.com
Wed Oct 17 05:08:35 CEST 2007
I think its your parameterization that is problematic.
ED50^hill is tough for it to work with since both are varying.
Try reparameterizing using ED50hill = ED50^hill as a parameter
so that the parameters become Emax, ED50hill and hill. You
can back transform afterwards.
On 10/16/07, Lanre Okusanya <lanre.okusanya at gmail.com> wrote:
> Hello all, I am having a problem with nls. I have such data as shown below,
> Dose var
> 0 0.000000
> 100 -1.318178
> 200 -1.562425
> 400 -3.579960
> 1200 -3.788662
> however, when I call nls as shown below,
> + start=list(Emax=-4,EC50=269,hill=1),trace=T,data=foo)
> i get the response below.
> 1.759088 : -4 269 1
> Error in numericDeriv(form[], names(ind), env) :
> Missing value or an infinity produced when evaluating the model
> if i remove the hill variable, it works. can someone help me out with
> what I am coding wrong.
> R-help at r-project.org mailing list
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
More information about the R-help