[R-sig-ME] simulate() fails for poisson lmer fits

[William Valdar]

Hello,

I wish to simulate() from a fitted Poisson GLMM. Both lmer() and lmer2() 
from lme4 (version info at the bottom) fail, apparently due to bugs. 
Here's a test case:

counts <- data.frame(
         count  = c(8, 3, 0, 3, 0, 9, 0, 11, 4, 7, 0, 0, 0, 4, 3, 6, 3,
                 15, 11, 9),
         batch = c(3.1, 3.1, 3.1, 3.3, 3.3, 3.3, 3.2, 3.12, 3.8, 3.11,
                 3.4, 3.4, 3.4, 3.4, 3.5, 3.5, 3.5, 3.5, 3.6, 3.6),
         weight = c(324.4, 372.5, 352.7, 379.6, 388.1, 431, 448.4, 377.3,
                 376.5, 358.4, 356, 351.4, 350.8, 332.1, 334.5, 392, 370.5,
                 409.7, 375, 318.5))

fit <- lmer(count ~ weight + (1|batch),  family=poisson, data=counts)
# Error: inherits(object, "lmer") is not TRUE

fit <- lmer2(count ~ weight + (1|batch),  family=poisson, data=counts)
simulate(fit)
# CHOLMOD error: X and/or Y have wrong dimensions
# Error in crossprod(object at ZXyt, c(unlist(lapply(seq_along(re), 
# function(k) (t(cholL[[k]]) %*%  :
#        Cholmod error 'X and/or Y have wrong dimensions' at 
# file:../MatrixOps/cholmod_sdmult.c, line 90

Is there a quick fix for either of these two? Otherwise, is there an 
alternative (I've checked objects produced by nlme, glmmPQL, GLMMGibbs 
with no luck)? I am using lme4 0.99875-6 version R 2.5.1 on Windows XP.

Many thanks,

Will

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Dr William Valdar               ++44 (0)1865 287 589
Wellcome Trust Centre           valdar at well.ox.ac.uk
for Human Genetics, Oxford      www.well.ox.ac.uk/~valdar