[R] Problems with nlme: Quinidine example

rich@mi.fu-berlin.de rich at mi.fu-berlin.de
Thu Jul 7 13:36:59 CEST 2005

This concerns the "Clinical Study of Quinidine" example on page 380
of the book "Mixed-Effects Models in S and S-PLUS" by Pinheiro and Bates (2000).

I have tried to reproduce the example, but get an error:

> library(nlme)
> fm1Quin.nlme <- nlme(conc ~ quinModel(Subject, time, conc, dose, interval, lV,
lKa, lCl),
+                      data=Quinidine,
+                      fixed=lV + lKa + lCl ~ 1,
+                      random=pdDiag(lV + lCl ~ 1),
+                      groups= ~ Subject,
+                      start=list(fixed=c(5, -0.3, 2)),
+                      na.action=na.pass, naPattern= ~ !is.na(conc))
Error in solve.default(estimates[dimE[1] - (p:1), dimE[2] - (p:1), drop =
        system is computationally singular: reciprocal condition number =

 - I am running R version 2.1.0 on Linux.
 - The only difference between the code in the book and the code above is
   that I use na.pass instead of na.include for the na.action argument, but
   I don't think this is significant.

I would appreciate help from anybody who has been able to get this example to

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