[R-sig-ME] nlmer function

[Federico Calboli]

> On 8 Jul 2015, at 11:18, elham haem <elhamhaem at gmail.com> wrote:
> 
> 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:
> 
> 
> 
>> 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 )
> 
> 
> 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?
> 

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 )




> 
> Thanks in advance
> 
> Elham Haem
> 
> 	[[alternative HTML version deleted]]
> 
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--
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