[R-sig-ME] Error when using models with lmer

[Douglas Bates]

On Tue, Feb 7, 2012 at 2:03 PM, Olga Vitek <ovitek at stat.purdue.edu> wrote:
> Hello,
>
> I am executing the following code
>
>> library("lme4")
>> library(faraway)
>> data(penicillin)
>> fit4 <- lmer(yield ~ treat + (1|blend), penicillin)
>
> and the lines below generate error messages
>
>> library(gmodels)
>> ci(fit4)

Yes.  Why would you want to try to create a vector from an S4 fitted
model object?

It almost never makes sense to use

c(foo)

Most of the time when people use that idiom what they really mean is

foo

(I say "almost never" because in the old days many of us would use
c(myMatrix) to create a vector from a matrix.  The preferred form is
now as.vector(myMatrix).)

> Error in as.vector(data) :
>  no method for coercing this S4 class to a vector
>
>> contrast.function <- c(0, -1, 0, 0)
>> test.result <- estimable(fit4, contrast.function)
> Error in as.vector(data) :

I assume that the "estimable" function is in the gmodels package, so
you should contact the author of that package about this.

>  no method for coercing this S4 class to a vector
>
>
> This worked with with lme4_0.999375-40 and R version 2.13.1, but not with lme4_0.999375-42 and R version 2.14.1.
>
> Would you have suggestions on how to make this work?
> Thank you in advance
> Olga Vitek
>
>> sessionInfo()
> R version 2.14.1 (2011-12-22)
> Platform: i386-apple-darwin9.8.0/i386 (32-bit)
>
> locale:
> [1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
>
> attached base packages:
> [1] stats     graphics  grDevices utils     datasets  methods   base
>
> other attached packages:
> [1] gmodels_2.15.1   faraway_1.0.5    lme4_0.999375-42 Matrix_1.0-3     lattice_0.20-0
>
> loaded via a namespace (and not attached):
> [1] gdata_2.8.2   grid_2.14.1   gtools_2.6.2  MASS_7.3-16   nlme_3.1-102  stats4_2.14.1 tools_2.14.1
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