On 8/3/2009 1:15 PM, Hongwei Dong wrote: > Hi, R users, > I'm using the "lme" function in R to estimate a 2 level mixed effects > model, in which the size of the subject groups are different. It turned out > that It takes forever for R to converge. I also tried the same thing in SPSS > and SPSS can give the results out within 20 minutes. Anyone can give me some > advice on the lme function in R, especially why R does not converge? Thanks.
Harry: You are much more likely to get helpful advice if you include the code you used to attempt to fit the model and a brief description of the data. For example, something along these lines but for your data and model: library(nlme) fm2 <- lme(distance ~ age + Sex, data = Orthodont, random = ~ 1) str(Orthodont) Classes ‘nfnGroupedData’, ‘nfGroupedData’, ‘groupedData’ and 'data.frame': 108 obs. of 4 variables: $ distance: num 26 25 29 31 21.5 22.5 23 26.5 23 22.5 ... $ age : num 8 10 12 14 8 10 12 14 8 10 ... $ Subject : Ord.factor w/ 27 levels "M16"<"M05"<"M02"<..: 15 15 15 15 3 3 3 3 7 7 ... $ Sex : Factor w/ 2 levels "Male","Female": 1 1 1 1 1 1 1 1 1 1 ... - attr(*, "outer")=Class 'formula' length 2 ~Sex .. ..- attr(*, ".Environment")=<environment: R_GlobalEnv> - attr(*, "formula")=Class 'formula' length 3 distance ~ age | Subject .. ..- attr(*, ".Environment")=<environment: R_GlobalEnv> - attr(*, "labels")=List of 2 ..$ x: chr "Age" ..$ y: chr "Distance from pituitary to pterygomaxillary fissure" - attr(*, "units")=List of 2 ..$ x: chr "(yr)" ..$ y: chr "(mm)" - attr(*, "FUN")=function (x) ..- attr(*, "source")= chr "function (x) max(x, na.rm = TRUE)" - attr(*, "order.groups")= logi TRUE hope this helps, Chuck > Harry > > [[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. -- Chuck Cleland, Ph.D. NDRI, Inc. (www.ndri.org) 71 West 23rd Street, 8th floor New York, NY 10010 tel: (212) 845-4495 (Tu, Th) tel: (732) 512-0171 (M, W, F) fax: (917) 438-0894 ______________________________________________ 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.
