[CP2K:3992] creating a sparse dbcsr matrix
aml... at ucdavis.edu
Tue Aug 28 22:35:39 CEST 2012
Thanks! Our matrices fit on one computer so the filter works for showing
linear scaling for now.
On Monday, August 27, 2012 2:35:28 AM UTC-6, Urban wrote:
> Hi Adam,
> On Fri, 2012-08-24 at 16:34 -0700, Adam wrote:
> > Hi,
> > I'm creating dbcsr matrices out of dense 2d fortran arrays. However
> > few elements are non-zero values, and I'd like to build a dbcsr matrix
> > in sparse format so I can see speed ups when doing multiplication. The
> > examples provided with the dbcsr package only show how to build dense
> > random matrices. Is there any examples on building sparse matrices, or
> > can you tell me how a sparse matrix is built? Right now timing my code
> > it is scaling closer to order n^3 than n. Any help is much
> > appreciated.
> There are generally two basic approaches to having a sparse matrix:
> either you know the sparsity pattern beforehand and store only the
> appropriate blocks in the matrix or you completely fill the matrix and
> then filter it (using the dbcsr_filter* subroutine(s)). The latter is
> easier to do but it's really only a hack. It only works in cases where
> dense the matrix fits in memory; however, since it's still distributed,
> it's usually not a show-stopper.
> > Thanks,
> > Adam
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