Pinheiro/Bates Soybean nlme failure
On Wed, 17 Jan 2001, Dieter Menne wrote:
Dear Mixed Effect Friends, Somehow, R(1021, Windows) seem to run differently from S Plus: The soybean example from Pinheiro/Bates on page 290 fails in R. (Soybean1 is Soybean with the NA and "critical" case removed. Same procedure with full Soybean).
fm1Soy.lis<-nlsList(weight~SSlogis(Time,Asym,xmid,scal),data=Soybean1) fm1Soy.nlme<-nlme(fm1Soy.lis)
Error: Singularity in backsolve at level 0, block 1 In addition: There were 50 or more warnings (use warnings() to see the first 50)
warnings()
Warning messages: 1: Singular precision matrix in level -1, block 1 2: Singular precision matrix in level -1, block 1
It is not the only such. nlme-3.1-x, x >=8 has a different algorithm and fails much more often for me than nlme-3.1-6, say. Both fail more often than nlme 3.3 on S-PLUS (you didn't say what you were using). The Windows port of nlme does pass Rcmd check, so does run the examples correctly.
Brian D. Ripley, ripley at stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272860 (secr) Oxford OX1 3TG, UK Fax: +44 1865 272595 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._