1. We are not a "help desk", in the sense of being constituted by a software provider for customer support. This is a forum of volunteers. Not a big deal, but no guarantees and caveat emptor.
2. You may get a reply here, but there is another forum specifically for nlme (and its successor, lme4), r-sig-mixed-models, https://stat.ethz.ch/mailman/listinfo/r-sig-mixed-models . You should post there if you don't get useful help here. 3. I haven't used nlme in a long time, but your error message seems to suggest some issue with your data. You *may* need to provide the results of str(minitab) to get a useful answer (or I may simply not recognize an obvious issue in what you provided in your post). Bert Gunter "The trouble with having an open mind is that people keep coming along and sticking things into it." -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) On Thu, Apr 7, 2022 at 4:29 AM Rohan Richard via R-help <r-help@r-project.org> wrote: > > Dear Help Desk, > > I am trying to perform a non-linear regression (Sigmoid curves) using the R > package nlme. My field trial is a randomised complete block design (RCBD) > with 3 blocks and I would like to assess the block effect in the model. Do > you know how I can incorporate the block term in nlme function? > > So far I tried the following code and it did not work and I an error error > message: > > # code > minitab$NDVI<-as.factor(minitab$NDVI) > modnlme1 <- nlme(NDVI ~ a + d / (1 + exp(-b * (DegreeDay - m)) ), data = > minitab, > random =a + d + b + m~ 1|Block, > fixed = list(a ~ Lines1, d~Lines1,b ~ Lines1, m ~ Lines1), > weights = varPower(), > start=c(b=0.5,c=3,d=0.4, e=700), control = list(msMaxIter = > 200)) > > #Error message > Error in `contrasts<-`(`*tmp*`, value = contr.funs[1 + isOF[nn]]) : > contrasts can be applied only to factors with 2 or more levels > > Could you please kindly help me? > > Thank you in advance, > > Best wishes, > > Rohan > > Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows > > > Rothamsted Research is a company limited by guarantee, registered in England > at Harpenden, Hertfordshire, AL5 2JQ under the registration number 2393175 > and a not for profit charity number 802038. > > [[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. ______________________________________________ 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.
