nlmer function

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?


Thanks in advance

Elham Haem