R help - Mar 2007 - Removing duplicated rows in a matrix, with missing data as wildcards

I'd like to remove duplicated rows within a matrix, with missing data
being treated as wildcards.

For example
> x <- matrix((1:3), 5, 3)
> x[4,2] = NA
> x[3,3] = NA
> x
    [,1] [,2] [,3]
[1,]    1    3    2
[2,]    2    1    3
[3,]    3    2   NA
[4,]    1   NA    2
[5,]    2    1    3

I would like to obtain

     [,1] [,2] [,3]
[1,]    1    3    2
[2,]    2    1    3
[3,]    3    2   NA
>From the R-help archives, I learned about unique(x) and duplicated(x).
However, unique(x) returns
> unique(x)
    [,1] [,2] [,3]
[1,]    1    3    2
[2,]    2    1    3
[3,]    3    2   NA
[4,]    1   NA    2

and duplicated(x) gives
> duplicated(x)
[1] FALSE FALSE FALSE FALSE  TRUE

I have tried various na.action 's but with unique(x) I get errors at best.

e.g.
> unique(x, na.omit(x))
Error: argument 'incomparables != FALSE' is not used (yet)

How I might tackle this?

Thanks,

-stacey

--
-stacey lee thompson-
Stagiaire post-doctorale
Institut de recherche en biologie v?g?tale
Universit? de Montr?al
4101 Sherbrooke Est
Montr?al, Qu?bec H1X 2B2 Canada
stacey.thompson at umontreal.ca