[petsc-users] MatCreateMPIAIJWithSplitArrays for symmetric matrix?

[Jed Brown]

On Mon, Nov 8, 2010 at 13:47, Daniel Langr <daniel.langr at gmail.com> wrote:

> Great, helps much, that is something I was hoping for :). As for now, we
> can generate matrix in-order. In the future it seems we will need to
> generate matrix in "transposed" order, e.g. row-by-row order for the lower
> triangular part. But then I suppose we will need to use MatMultTranspose()
> or MatCreateTranspose() if the performance won't suffer much (I have not
> tried it yet, so I have no idea about it for now.)


Well, the distinguishing property of symmetric matrices is that they are
equal to their transpose. :-)

For non-symmetric matrices, MatMultTranspose (perhaps accessed as MatMult
via MatCreateTranspose) is about the same speed as MatMult.

Jed
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