[R] Correlated frailty model

[ah06981 at studbocconi.it]

Dear R-help,
I am trying to a estimate a correlated frailty model. My dataset is 
made up of 40000 observations. I would like to know if it is too big or 
I have done some mistakes in the following code.

group<-paste(usa$id,usa$mob)
mixed.logn<-coxme(Surv(yearspan)~ south+mod, data=usa,random= ~ 1|group)
Errore in matrix(0, dd[1], dd[2], dimnames = x at .Dimnames) :        non 
è possibile allocare un vettore di lunghezza 1600000000
(It is not possible to use a vector of leght 1600000000)
Inoltre(Also): Warning message:
The initial fit took 6  steps, which is bigger than the inner.iter  
paramter.  Consider increasing the latter in: coxme.fit(X, Y, strats, 
offset, init, control, weights = weights,  Thank you
Silvia