[R] Problems with nlme: Quinidine example

From: <rich_at_mi.fu-berlin.de>
Date: Thu 07 Jul 2005 - 21:36:59 EST


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 = FALSE]) :
        system is computationally singular: reciprocal condition number = 6.61723e-17

Note:

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



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