[R] nls + quasi-poisson distribution

[Suresh Krishna]

Hello R-helpers,

I would like to fit a non-linear function to data (Discrete X axis,  
over-dispersed Poisson values on the Y axis).

I found the functions gnlr in the gnlm package from Jim Lindsey: this can  
handle nonlinear regression equations for the parameters of Poisson and  
negative binomial distributions, among others. I also found the function  
nls2 in the software package accompanying the book "Statistical tools for  
nonlinear regression" by Huet et al: this can handle nonlinear regression  
with Poisson distributed Y-axis values.

I was wondering if there was any other option: specifically, any option  
that handled nonlinear fitting with quasi-Poisson distributions (to handle  
the overdispersion).

This is a very new area for me, and I am still trying to figure out the  
best way to do this, so I would appreciate any and all pointers.

Thanks much, Suresh