[R] Pinheiro/Bates Soybean nlme failure

Dieter Menne dieter.menne at menne-biomed.de
Wed Jan 17 21:26:20 CET 2001

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

Dr. Dieter Menne
Biomed Software
72074 Tübingen
Tel (49) (7071) 52176
FAX (49) (7071) 55 10 46
dieter.menne at menne-biomed.de

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