[Trilinos-Users] Epetra Matrices for ML from Metis Partitioned Matrices

[Marzio Sala]

Hi Greg,

the ML preconditioning class works with Epetra_RowMatrix derived objects. It
requires that each row is *entirely* owned by exactly one processor. If you
can reproduce this situation, it is quite easy to wrap your distributed
matrix format as an Epetra_RowMatrix, then call ML. The ML user's guide
describes how local and global indices are managed by ML.

If you partition the grid elements, then probably you first need to "unify"
the rows corresponding to boundary nodes, then call ML. Classes like
Epetra_FECrsMatrix can make this step easy.

-Marzio


On 5/10/06, gjl7 at et.byu.edu <gjl7 at et.byu.edu> wrote:
>
> We are linking Trilinos with another code.  The finite element mesh has
> already been partitioned using metis and the local matrices are already
> set up in a compressed sparse row format and distributed on each
> processor.  Now, we want to use ML to solve these matrices, with ML
> realizing these matrices are coupled due to node overlap.  Is there an
> example showing how to set up the Epetra matrices so ML realizes these
> matrices are linked by the overlapping nodes?  If there is no documented
> example, what would you recommend?  Thanks.
>
> Greg Larson
>
>
>
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