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nlmer function

3 messages · elham haem, Federico Calboli

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Dear lme4 authors,


I have studied ?Mixed models in R using the lme4 package Part 6: Nonlinear
mixed models? by Douglas Bates. In this tutorial, there are some codes to
fit nonlinear mixed models for Theoph data. The codes are as fallows:
+    0+ lKe+lKa+lCl +(0+ lKe| Subject )+(0+ lKa| Subject )

+    +(0+ lCl| Subject ), nAGQ =0, Theoph ,

+     start = Th.start , verbose = TRUE )


I have 2 problems:

1. when I run these codes, I see this error:

Error: unexpected '=' in:

"+ +(0+ lCl| Subject ), nAGQ =0, Theoph ,

+ start ="

 2. I want to add a covariate (like age) to CL parameter. How should I
modify above codes?


Thanks in advance

Elham Haem
4 days later
#
When you copy code verbatim from a pdf you copy the formatting, hence the code is unlikely to work.  This, which is lifted verbatim and fixed in a text editor by removing extra spaces in the formatting, and the line breaks, works.

library(lme4)
data(Theph)
Th.start <- c( lKe = -2.5 , lKa = 0.5 , lCl = -3)
nm1 <- nlmer ( conc ~ SSfol ( Dose , Time , lKe , lKa , lCl ) ~ 0+ lKe + lKa + lCl +(0+ lKe | Subject )+(0+ lKa | Subject ) +(0+ lCl | Subject ), nAGQ =0 , Theoph , start = Th.start , verbose = TRUE )
--
Federico Calboli
Ecological Genetics Research Unit
Department of Biosciences
PO Box 65 (Biocenter 3, Viikinkaari 1)
FIN-00014 University of Helsinki
Finland

federico.calboli at helsinki.fi
#
the most astute will notice the data is called ?Theoph' not ?Theph?
--
Federico Calboli
Ecological Genetics Research Unit
Department of Biosciences
PO Box 65 (Biocenter 3, Viikinkaari 1)
FIN-00014 University of Helsinki
Finland

federico.calboli at helsinki.fi