[R-sig-ME] SVN version of lme4 has a space-saving version of lmer2

Douglas Bates bates at stat.wisc.edu
Mon Mar 26 15:48:38 CEST 2007

The SVN version of lme4, available at


has a new version of lmer2 that should require less memory on large
model fits.  It creates the entire lmer2 object at once rather than
creating the mer2 object then later creating the lmer2 object from
that.  This should avoid a copy operation involving potentially large

If you have a very large model fit to create please try out the new
version.  It does require R-2.5.0 so you will need to build that
first.  If that is not feasible and you can allow me access to the
data then I would be pleased to run the tests.

The largest test for which I have real data is a model fit to the star
data (about 25000 observations and approximately the same number of
random effects) and that ends up taking too little memory (12 MB) to
be a real test of the memory growth.

The optional argument frame = FALSE (don't save the model frame) cuts
down on the size of the returned object, sometimes dramatically.

More information about the R-sig-mixed-models mailing list