[R] nlme

[Jeff Newmiller]

Wild guess: Santiago is putting a and b in his formula when they are the coefficients he wants to extract? 

If Mr S wants better answers he needs to read about reproducibility and avoid HTML format email. 
-- 
Sent from my phone. Please excuse my brevity.

On October 24, 2016 2:58:42 PM CDT, William Dunlap via R-help <r-help at r-project.org> wrote:
>> summary(nlme(Btronc~a+b*dbh**2*haut, data=cbind(dat,g="a"),
>fixed=a+b_1,
>> start=start,
>>
>> groups=~g, weights=varPower(form=~dbh)))
>
>Shouldn't 'fixed' be a formula?  Perhaps a+b~1?
>
>
>Bill Dunlap
>TIBCO Software
>wdunlap tibco.com
>
>On Mon, Oct 24, 2016 at 9:03 AM, Santiago Bueno <swbueno at gmail.com>
>wrote:
>
>> Dear people:
>>
>>
>> I am getting the following error when trying to run the piece of code
>> below. Any insights??
>>
>>
>>
>> Error in nlme.formula(Btronc ~ a + b * dbh^2 * haut, data =
>cbind(dat,  :
>>
>>   object 'a' not found
>>
>>
>>
>> library(nlme)
>>
>> start <- coef(lm(Btronc~I(dbh**2*haut),data=dat))
>>
>> names(start) <- c("a","b")
>>
>> summary(nlme(Btronc~a+b*dbh**2*haut, data=cbind(dat,g="a"),
>fixed=a+b_1,
>> start=start,
>>
>> groups=~g, weights=varPower(form=~dbh)))
>>
>>
>> Best,
>>
>>
>> Santiago
>>
>>         [[alternative HTML version deleted]]
>>
>> ______________________________________________
>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide http://www.R-project.org/
>> posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>
>	[[alternative HTML version deleted]]
>
>______________________________________________
>R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>https://stat.ethz.ch/mailman/listinfo/r-help
>PLEASE do read the posting guide
>http://www.R-project.org/posting-guide.html
>and provide commented, minimal, self-contained, reproducible code.