[R] env() for lme4

[Douglas Bates]

On Tue, Feb 23, 2010 at 2:17 AM, Dieter Menne
<dieter.menne at menne-biomed.de> wrote:

> Marianne Promberger-3 wrote:
>>
>> Yes, I believe you need library(lme4a), the development version of lme4.
>>
>> ....
>> (But then something didn't work with profile() on my particular model
>> but I forgot what it was -- haven't had time to pursue this yet)
>>
>>
>
> profile() worked for me (="output looked reasonable"), so it looks like it
> really is a problem with special model.

Well, that and the fact that it is not really well documented.  When
you have problems with profiling you can try to cut down the step
size.  If you check the actual code used in Chapter 1 of the book I am
writing you will see that I cheat and call profile as

pr01 <- profile(fm01, delta = 0.2)

That mysterious, and undocumented, delta = 0.2 forces smaller step
sizes when constructing the profiles (step size in the sense of the
amount of the shift of the parameter being profiled from its current
position to its next position).  Sometimes large steps cause inability
to converge at the new value.