Unless I misunderstand, I think you might want the nlsList function from the nlme package. It will let you fit a nonlinear model for grouped data. You use "|" to separate the model formula from the grouping factor.
Rick ________________________________________ From: r-help-boun...@r-project.org [r-help-boun...@r-project.org] on behalf of Andrew Robinson [a.robin...@ms.unimelb.edu.au] Sent: Friday, April 29, 2011 8:05 PM To: Cristiano Yuji Sasada Sato Cc: r-help@r-project.org Subject: Re: [R] Analysis and graphics by groups hi Christiano, the error is that FUN is not a function. That is true, the argument that you are passing to FUN is a different class. Instead of fx, for example, where fx is your model code below, try to write it as a function of the arguments that you want to split by Cerca. You might try to construct a minimal, reproducible, commented example to help us explain what you need to do. I don't have the gapply function and I don't know which package it is in (perhaps you could provide that information next time) so I can't help more than that. Andrew On Fri, Apr 29, 2011 at 04:31:51PM -0300, Cristiano Yuji Sasada Sato wrote: > Hello, > > This is my first post in this e-mail list and I hope it's enough to justify > calling for help. In case it's not, sorry. > > I'm trying to do analysis and graphics using a factor as a criteria to split > data and do the analysis/graphics for each subset of data. > > Right now what I'm trying to do is to fit and plot the following logistic > model, according to a third variable named "Cerca": > dm_fit_T<-nls(nDMTRBgm2~(K/(1+((K-nDMTRBgm2.T.1)/nDMTRBgm2.T.1)*exp(-r))),perieph,start=list(K=3,r=0.2),trace=T) > > I've found a function called gapply which seems to be what I need, but it > doesn't seem to work. This is the argument I've used: > gapply(perieph,FUN=nls(nDMTRBgm2~(K/(1+((K-nDMTRBgm2.T.1)/nDMTRBgm2.T.1)*exp(-r))),perieph,start=list(K=3,r=0.2),trace=T),groups="Cerca") > > But I get this error message returned: > > Error in get(as.character(FUN), mode = "function", envir = envir) : > object 'FUN' of mode 'function' was not found > > Can you help me doing this non-linear regression by groups work? > > Also, after I manage making the regression, I'd also need fitting a line to > the nDMTRBgm2~nDMTRBgm2.T.1 data using the same model above. I've used > plotfit to do that with one nlm data set. Is it possible to fit each group > trend line and data with different colours/symbols in one same graphic? > > Thank you, > Cristiano > > -- > Cristiano Yuji Sasada Sato > Doutorando > Programa de P?s-Gradua??o em Ecologia e Evolu??o - IBRAG / UERJ > Laborat?rio de Ecologia de Rios e C?rregos > Departamento de Ecologia - Universidade do Estado do Rio de Janeiro > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list > 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 Program Manager, ACERA Department of Mathematics and Statistics Tel: +61-3-8344-6410 University of Melbourne, VIC 3010 Australia (prefer email) http://www.ms.unimelb.edu.au/~andrewpr Fax: +61-3-8344-4599 http://www.acera.unimelb.edu.au/ Forest Analytics with R (Springer, 2011) http://www.ms.unimelb.edu.au/FAwR/ Introduction to Scientific Programming and Simulation using R (CRC, 2009): http://www.ms.unimelb.edu.au/spuRs/ ______________________________________________ R-help@r-project.org mailing list 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. ______________________________________________ R-help@r-project.org mailing list 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.
