From: Douglas Bates <dmbates_at_gmail.com>

Date: Sat 20 Aug 2005 - 00:12:40 EST

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Sat Aug 20 00:18:35 2005

Date: Sat 20 Aug 2005 - 00:12:40 EST

On 8/18/05, François Morneau <francois.morneau@cirad.fr> wrote:

> Hello,

*>
**> I want to fit a Gompertz model for tree diameter growth that depends on a 4
**> levels edaphic factor ('Drain') and I don't manage to introduce the factor
**> variable in the formula.
**> Dinc is the annual diameter increment and D is the Diameter.
**>
**> >treestab
**> > Dinc D Drain
**> [1,] 0.03 26.10 2
**> [2,] 0.04 13.05 1
**> [3,] 0.00 24.83 1
**> [4,] 0.00 15.92 4
**> [5,] 0.00 12.25 4
**> [6,] 0.00 11.78 4
**> [7,] 0.00 16.87 4
**> [8,] 0.00 15.12 4
**> [9,] -0.01 13.53 4
**> [10,] 0.04 16.55 3
**> [11,] 0.025 16.07 3
**> [12,] 0.00 30.24 3
**> [13,] 0.06 15.28 2
**> etc…
**> >contrasts(Drain)<-contr.sum(4)
**> >mymodel<-nls(Dinc~r*(1+Drain)*D*log(Asym/D), data=treestab, start(r=0.05,
**> Asym=40))
**>
**> Error in numericDeriv(form[[3]], names(ind), env) :
**> Missing value or an infinity produced when evaluating the model
**> In addition: Warning messages:
**> 1: + not meaningful for factors in: Ops.factor(1, Drain)
**> 2: + not meaningful for factors in: Ops.factor(1, Drain)
*

It is not clear to me what you are trying to do. Can you give us a bit more information such as how many parameter estimates you expect to obtain and what they would represent?

*>
*

> Do I need to use another function instead of nls to correctly include the

*> factor 'Drain' ?
**>
**> Thanks,
**>
**> François
**>
**> ______________________________________________
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**> https://stat.ethz.ch/mailman/listinfo/r-help
**> PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
**>
*

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Sat Aug 20 00:18:35 2005

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