I meant "sparse matrix", sorry for the typo.
Feng
On Sat, Jan 29, 2011 at 7:02 PM, Feng Li <m@feng.li> wrote:
> Dear R,
>
> I have a simple question concerning with a special case of sparse matrix
> multiplications. Say A is a 200-by-10000 dense matrix. B is a
10000-by-10000
> block- diagonal matrix, and each diagonal block B_i is 100-by-100. The
usual
> way I did A%*%B will take about 30 seconds which is to time consuming
> because I have to do this thousands of times. I also tried to partition A
> into 100 small blocks and use mapply function to multiply by each B_i, but
> that is even slower.
>
> I am wondering if there is an efficient way to perform this type of
> multiplication with R?
>
> Thanks in advance!
>
> Feng
>
> --
> Feng Li
> Department of Statistics
> Stockholm University
> 106 91 Stockholm, Sweden
> http://feng.li/
>
>
--
Feng Li
Department of Statistics
Stockholm University
106 91 Stockholm, Sweden
http://feng.li/
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