R help - Sep 2009 - Syntax for crossed random effects in nlme

Hello R users, 
I've read the posts on this topic, and had a look at the R documentation for
nlme, but I can't seem to make this work. I'd like to be able to fit a
mixed
effects model with crossed random effects, but also be able to specify the
covariance matrix structure for the residuals. Here's the syntax using the
lmer function in lme4 (which doesn't currently allow alternate error
covariance structures). Does anybody know how to transform this to work with
nlme?

fit = lmer(data$DV ~ X + time + (X*time) + (1|Item_Number) + (1|Subject),
data)

Much appreciated, 
Ben Amsel
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Hi Ben,

Pinheiro and Bates 2000 is the "real" documentation for nlme.  See the
Cell Culture Bioassay example starting on pg 163 for a demonstration
of fitting crossed random effects using pdIdent and pdBlocked objects.

hth,
Kingsford

On Tue, Sep 1, 2009 at 6:44 AM, bamsel<benamsel at gmail.com>
wrote:
>
> Hello R users,
> I've read the posts on this topic, and had a look at the R
documentation for
> nlme, but I can't seem to make this work. I'd like to be able to
fit a mixed
> effects model with crossed random effects, but also be able to specify the
> covariance matrix structure for the residuals. Here's the syntax using
the
> lmer function in lme4 (which doesn't currently allow alternate error
> covariance structures). Does anybody know how to transform this to work
with
> nlme?
>
> fit = lmer(data$DV ~ X + time + (X*time) + (1|Item_Number) + (1|Subject),
> data)
>
> Much appreciated,
> Ben Amsel
> --
> View this message in context:
http://www.nabble.com/Syntax-for-crossed-random-effects-in-nlme-tp25239714p25239714.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
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> PLEASE do read the posting guide
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>