Ben, thanks a lot for your quick reply. Scales of x1 and x2 covariates were
too different and this fact may have caused some problem. I have made them
similar by dividing one of them by 1000 and now the analysis works.
Best regards,
Elena


2010/2/1 Ben Bolker <bolker@ufl.edu>

>  elena daniela concepcion <elenadconcepcion <at> gmail.com> writes:
>
> >
> > Hi, I'm trying to make multiple poisson regressions with the MLE2
> command.
> > I have used the following expression, but I receive an error message:
> >
> > poisfit <- mle2(y ~ dpois(exp(b0 + b1*x1 + b2*x2)), start=list(b0=1,
> b1=1,
> > b2=1), data=data1)
> > Error in optim(par = c(1, 1, 1), fn = function (p)  :
> >   non-finite initial value 'vmmin'
> >
> > I have changed initial values using coefficient values given by the GLM
> > standard procedure but it still doesn't work.
> > Do someone knows where is the problem?
> >
>
>   There's nothing obviously wrong here.  A reproducible example
> would be very helpful ... this *should* give the same result
> as  glm(y~x1+x2,family=poisson,data=data1) ...  What is
> with(data1,range(exp(b0+b1*x1+b2*x2))) ?
>
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