Thanks Andrew. I am now trying but without much success. I don't now how to give start values for the factor?. Could you give me an example solution with my toy example?
a<-as.factor(c(rep(1,50),rep(0,50))) independ<-1:100 respo<-rep(NA,100) respo[a==1]<-(independ[a==1]^2.3)+2 respo[a==0]<-(independ[a==0]^2.1)+3 library(nlme) gnls(respo~independ^b+a,start=list(b=1.8)) Many thanks. Manu --- Andrew Robinson <[EMAIL PROTECTED]> escribió: > Manuel, > > I don't think that it works very easily. Instead, > try gnls() in the > nlme package. > > Cheers > > Andrew > > On Thu, Apr 20, 2006 at 11:18:02AM +0200, Manuel > Gutierrez wrote: > > Is it possible to include a factor in an nls > formula? > > I've searched the help pages without any luck so I > > guess it is not feasible. > > I've given it a few attempts without luck getting > the > > message: > > + not meaningful for factors in: > > Ops.factor(independ^EE, a) > > > > This is a toy example, my realworld case is much > more > > complicated (and can not be solved linearizing an > > using lm) > > a<-as.factor(c(rep(1,50),rep(0,50))) > > independ<-rnorm(100) > > respo<-rep(NA,100) > > respo[a==1]<-(independ[a==1]^2.3)+2 > > respo[a==0]<-(independ[a==0]^2.1)+3 > > > nls(respo~independ^EE+a,start=list(EE=1.8),trace=TRUE) > > > > Any pointers welcomed > > Many Thanks, > > Manu > > > > ______________________________________________ > > [email protected] mailing list > > https://stat.ethz.ch/mailman/listinfo/r-help > > PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.html > > -- > Andrew Robinson > Department of Mathematics and Statistics > Tel: +61-3-8344-9763 > University of Melbourne, VIC 3010 Australia > Fax: +61-3-8344-4599 > Email: [EMAIL PROTECTED] > http://www.ms.unimelb.edu.au > ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
