[petsc-users] looking for examples on solving linear systems of matrix-free matrices

[Matthew Knepley]

On Sat, Sep 4, 2010 at 10:26 AM, jinshan wu <wujinshan at yahoo.com> wrote:

> Hi all, I am new to this list. But it seems to have a lot of resources and
> friendly people here.
>
> I need to solve a huge linear system. In order to save some memory, I am
> thinking to store the matrices in its own data structure other than in real
> matrices. I understand that petsc can do that via GMRES (and others)
> without accessing matrix elements . So my question is where can we find
> some
> example? I am perfectly fine with supplying the matrix-vector product part
> by my
> own. I need more infor on how to connect it to the solver in petsc.
>

You can use

http://www.mcs.anl.gov/petsc/petsc-as/snapshots/petsc-current/docs/manualpages/Mat/MatCreateShell.html

There are links to examples on that page.


> Also another technical question: do we have to perform the preconditioner?
>

Usually, if you want it to be efficient.

   Matt


> thanks,
> Jinshan
>
>
>
>


-- 
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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