[R] How to solve allocation problem in lme() analysis?

[Petar Milin]

Hello!
I am running analysis on the data from 4 experiments, with approximately
4600 rows (cases). My working model is:
fitA1 = lme(RT~F1+F2+L,random=~1|Experiment/Subject,data=data)

Model works very fine, but if I try to check whether the effect of L
depends on Experiments/Subjects with:
fitA2 = lme(RT~F1+F2+L,random=~1+L|Experiment/Subject,data=data)
[with the idea to make: anova(fitA1,fitA2)]

> analysis crashes with the message:
> Error: cannot allocate vector of size 2481574 Kb
> In addition: Warning message:
> Fewer observations than random effects in all level 2 groups in:
> lme.formula(RT ~ F1 + F2 + L, random = ~1 + L | Experiment/Subject,

Can anyone help me with this issue? Thanks in advance.

Sincerely,
Petar Milin
Assistant Professor
Department of Psychology
University of Novi Sad
Serbia and Montenegro