[petsc-users] Dense matrix solver

[Matthew Knepley]

On Thu, Sep 19, 2013 at 8:30 PM, Jed Brown <jedbrown at mcs.anl.gov> wrote:

> Frank <fangxingjun0319 at gmail.com> writes:
>
> > Hi,
> >
> > I am thinking of solving a linear equations, whose coefficient matrix
> > has 27 nonzero diagonal bands(diagonal dominant). Does any body have any
> > idea about how this will perform? Do you have any recommendation about
> > which solver to choose?
>
> How far away from the diagonal are those bands, as a function of the
> grid size (if relevant)?
>
> http://scicomp.stackexchange.com/a/880/119
> http://scicomp.stackexchange.com/a/869/119


If your matrix/preconditioner has bandwidth K which is small and is
diagonally dominant,
you can solve it efficiently using
http://en.wikipedia.org/wiki/SPIKE_algorithm.

  Thanks,

      Matt


> > I have solved a 11 nonzero diagonal bands matrix equation with
> > "boomeramg", which is 50% solwer than 7 nonzero diagonal bands.
>
> This doesn't mean much of anything.  Send -log_summary if you have
> performance questions.
>
> Why does the subject of this email say "dense"?
>



-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener
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