On Wed, Jan 20, 2010 at 2:26 AM, Martin Maechler
<maech...@stat.math.ethz.ch> wrote:
> Scanning for 'Matrix' in old R-help e-mail, I found
>
>>>>>> "GA" == Gad Abraham <gabra...@csse.unimelb.edu.au>
>>>>>> on Fri, 27 Nov 2009 13:45:00 +1100 writes:
>
> GA> Hi,
> GA> I'd like to store large covariance matrices using Matrix classes.
>
> GA> dsyMatrix seems like the right one, but I want to specify just the
> GA> upper/lower triangle and diagonal and not have to instantiate a huge
> GA> n^2 vector just for the sake of having half of it ignored:
>
> GA> Dumb example:
> GA> M <- new("dsyMatrix", uplo="U", x=rnorm(1e4), Dim=as.integer(c(100,
> 100)))
> GA> diag(M) <- 1
>
> GA> This doesn't work:
> GA> M <- new("dsyMatrix", uplo="U", x=0, Dim=as.integer(c(100, 100)))
> GA> Error in validObject(.Object) :
> GA> invalid class "dsyMatrix" object: length of x slot != prod(Dim)
>
> GA> Is there an easier way of doing this?
>
> I think you want a "dspMatrix" ("sp" == "symmetric packed")
> instead.
>
> Before going into details: Is this topic still interesting to
> those involved almost two months ago?
Yes, please!
--
Gad Abraham
PhD Student, Dept. CSSE and NICTA
The University of Melbourne
Parkville 3010, Victoria, Australia
email: gabra...@csse.unimelb.edu.au
web: http://www.csse.unimelb.edu.au/~gabraham
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