[R] hurdle control and optim

[Achim Zeileis]

Please refrain from cross-posting. The same request was sent to the author 
of hurdle(), R-help, and StackOverflow (where it was already answered). 
Also, do provide self-contained and reproducible code as would be 
appropriate in any of the three cases.

On Mon, 17 Aug 2015, Matt Dicken wrote:

>
> I was hoping someone may be able to help with the following.
>
> I fit the model below using the pscl package. I am modelling catch data (about 17,000 entry points) so lots of zero's
>
> fit.hurdle.bin = hurdle(Catch ~ Beach + Region + Year+
>                      Decade + Month + Season + Whale+ Sex + Size+ meantemp +
>                      meanviz + offset(log(Length.nets..km.)),
>                      dist="poisson",zero.dist="binomial",link="logit",trace=T)
>
> The model output tells me that:
> Warning message: In sqrt(diag(object$vcov)) : NaNs produced (against year)
>
> I then use hurdle control with "L-BFGS-B" to set some parameter controls to solve this issue, but get the warning message:
> L-BFGS-B needs finite values of 'fn'
> In addition: Warning message:
> In optim(fn = countDist, gr = countGrad, par = c(start$count, if (dist ==  :
>  method L-BFGS-B uses 'factr' (and 'pgtol') instead of 'reltol' and 'abstol'
>
> How do I write the script for Hurdle control to solve these issues?
> Any help would be really appreciated
> All the best
> Matt
>
>
>
>
>
> Dr. Matt Dicken
> Senior Scientist
> Telephone: 0315660400 | Fax: 0315660493 | Email: matt at shark.co.za
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