Using parMetis in petsc for ordering

[Barry Smith]

On Thu, 11 Jan 2007, Dimitri Lecas wrote:

> Barry Smith a écrit :
> >   Dimitri,
> > 
> >    No, I think this is not the correct way to look at things. Load
> > balancing the original matrix is not neccessarily a good thing for
> > doing an LU factorization (in fact it is likely just to make the LU
> > factorization have much more fill and require much more floating
> > operations). 
> >   Packages like SuperLU_dist and Mumps have their own internal ordering
> > routines that are specifically for getting a good ordering for doing
> > the parallel LU factorization, you should just have these solvers
> > use them (which they do automatically).
> > 
> >    Barry
> > 
> > 
> > On Thu, 11 Jan 2007, Dimitri Lecas wrote:
> > 
> >   
> I'am no longer talking about doing LU factorization. But use iterative method
> for solving a linear system, like bicg. Like in the ex10. In this example i
> don't understand why using MatPartitioning.

  Please rephrase the question. Are you asking why one should do the partition 
or why one should not? Are you asking in the case where the matrix is read from
disk or generated in a parallel program?

> 
>