[R-sig-ME] bug in refit function?

[Alexandra Kuznetsova]

Hi all,

If I apply update function on the refit function, then the refitted model becomes the initial model. The example:

> set.seed(101)
> Y <- matrix(rnorm(1000),ncol=2)
> d <- data.frame(y1=Y[,1],  x=rnorm(100), f=rep(1:10,10))
> fit1 <- lmer(y1 ~ x+(1|f),data=d)
> fit2 <- refit(fit1, newresp = Y[,2])
> all.equal(fit1, update(fit2))
[1] TRUE

> sessionInfo()
R version 3.0.1 (2013-05-16)
Platform: x86_64-w64-mingw32/x64 (64-bit)

locale:
[1] LC_COLLATE=Danish_Denmark.1252  LC_CTYPE=Danish_Denmark.1252    LC_MONETARY=Danish_Denmark.1252
[4] LC_NUMERIC=C                    LC_TIME=Danish_Denmark.1252    

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] lme4_1.0-4      Matrix_1.0-12   lattice_0.20-15

loaded via a namespace (and not attached):
[1] grid_3.0.1    MASS_7.3-26   minqa_1.2.1   nlme_3.1-109  splines_3.0.1 tools_3.0.1  


Probably this is a bug?

Alexandra