On Thu, Sep 27, 2012 at 12:43 PM, Benedikt Gehr <benedikt.g...@ieu.uzh.ch> wrote: > now I feel very silly! I swear I was trying this for a long time and it > didn't work. Now that I closed R and restarted it it works also on my > machine. > > So is the only problem that my model is overparametrized with the data I > have? Probably.
> however shouldn't it be possible to fit an nls to these data? (Obviously) no. I suggest you do a little reading up on optimization. Over-parameterization creates high dimensional ridges. -- Bert > > thanks for the help > > Am 27.09.2012 21:27, schrieb Berend Hasselman: >> >> y_val<-115-118*exp(-0.12*(seq(1,100)+rnorm(100,0,0.8))) >> >x_val<-seq(1:100) >> >plot(y_val~x_val) >> >> > >summary(mod1<-nls(y_val~a-b*exp(-c*x_val),start=list(a=115,b=118,c=0.12))) >> > > > > -- > Benedikt Gehr > Ph.D. Student > > Institute of Evolutionary Biology and Environmental Studies > University of Zurich > Winterthurerstrasse 190 > CH-8057 Zurich > > Office 13 J 36b > Phone: +41 (0)44 635 49 72 > http://www.ieu.uzh.ch/staff/phd/gehr.html > > ______________________________________________ > 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. -- Bert Gunter Genentech Nonclinical Biostatistics Internal Contact Info: Phone: 467-7374 Website: http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm ______________________________________________ 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.
