[petsc-users] Avoid MUMPS ordering for distributed matrices?

[Jed Brown]

On Wed, Nov 23, 2011 at 05:43, Dominik Szczerba <dominik at itis.ethz.ch>wrote:

> In my procedure considerable time is spent to partition the domain.
> When using MUMPS as a solver for my matrix I see the message:
>
> "Ordering based on METIS"
>

This is an ordering to reduce fill in factorization, not to to partition
the domain. Last I heard, symbolic factorization was done in serial, which
explains why you find it taking a lot of time. The right hand side and
solution vectors are also passed on rank 0, which presents another
inefficiency/imbalance and memory bottleneck. Talk to the MUMPS developers
or use a different package if you don't like these properties.
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