Without access to the data, or commented, minimal, self-contained, reproducible code, it's pretty hard to speculate. I suggest that you reframe your question so that we can see what you can see.
Andrew On 25 October 2016 at 03:03, Santiago Bueno <swbu...@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@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. -- Andrew Robinson Deputy Director, CEBRA, School of Biosciences Reader & Associate Professor in Applied Statistics Tel: (+61) 0403 138 955 School of Mathematics and Statistics Fax: +61-3-8344 4599 University of Melbourne, VIC 3010 Australia Email: a.robin...@ms.unimelb.edu.au Website: http://www.ms.unimelb.edu.au/~andrewpr MSME: http://www.crcpress.com/product/isbn/9781439858028 FAwR: http://www.ms.unimelb.edu.au/~andrewpr/FAwR/ SPuR: http://www.ms.unimelb.edu.au/spuRs/ ______________________________________________ R-help@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.