[R] glmulti runs indefinitely when using genetic algorithm with lme4

[Thomas]

Dear List,

I'm using glmulti for model averaging in R. There are ~10 variables in my  
model, making exhaustive screening impractical - I therefore need to use  
the genetic algorithm (GA) (call: method = "g").

I need to include random effects so I'm using glmulti as a wrapper for  
lme4. Methods for doing this are available here  
http://www.inside-r.org/packages/cran/glmulti/docs/glmulti and there is  
also a pdf included with the glmulti package that goes into more detail.  
The problem is that when telling glmulti to use GA in this setting it runs  
indefinitely, even after the best model has been found.

This is the example taken from the pdf included in the glmulti package:

     library(lme4)
     library(glmulti)

     # create a function for glmulti to act as a wrapper for lmer:
     lmer.glmulti <- function (formula, data, random = "", ...) {
     lmer(paste(deparse(formula), random), data = data, REML=F, ...)
     }

     # set some random variables:
     y = runif(30,0,10) # mock dependent variable
     a = runif(30) # dummy covariate
     b = runif(30) # another dummy covariate
     c = runif(30) # an another one
     x = as.factor(round(runif(30),1))# dummy grouping factor

     # run exhaustive screening with lmer:
     bab <- glmulti(y~a*b*c, level = 2, fitfunc = lmer.glmulti, random =  
"+(1|x)")

This works fine. The problem is when I tell it to use the genetic  
algorithm:

     babs <- glmulti(y~a*b*c, level = 2, fitfunc = lmer.glmulti, random =  
"+(1|x)", method = "g")

It just keeps running indefinitely and the AIC does not change:

     After 19550 generations:
     Best model: y~1
     Crit= 161.038899734164
     Mean crit= 164.13629335762
     Change in best IC: 0 / Change in mean IC: 0

     After 19560 generations:
     Best model: y~1
     Crit= 161.038899734164
     Mean crit= 164.13629335762
     Change in best IC: 0 / Change in mean IC: 0

     After 19570 generations:
     Best model: y~1
     Crit= 161.038899734164
     Mean crit= 164.13629335762

     etc.

I have tried using calls that tell glmulti when to stop (deltaB = 0,  
deltaM = 0.01, conseq = 6) but nothing seems to work. I think the problem  
must lie with setting the function (?). It may be something really obvious  
however I'm new to R and I can't work it out.

I am using R v.2.15.0, glmulti v.1.0.6 and lme4 v.0.999999-0 on Windows.

Any help with this would be much appreciated.

Thomas