[R-sig-ME] R^2 for lme

[Balázs Lestár]

Dear All,

Can anybody tell me how to get the R^2 and adjusted R^2 for an lme object?
I found a formula, but when I checked it with an lm function, it didn't return the same result like summary(lm.model)$ r.squared.

l.B <- logLik (lme.model)
l.0 <- logLik ( lme ( y~ 1, random= ~1| a / b ) )
Rsq <- 1 - exp( - ( 2 / length(y ) * (l.B - l.0) ) )

Is there any packages that can help me?