[Trilinos-Users] AztecOO Convergence

[Ammar T. Al-Sayegh]

> Note that (using Ifpack as the preconditioner package) it is possible to
> have a different data distribution for the preconditioner than the rest of
> the problem.  In other words, you can leave the data distribution as-is for
> all of the problem except for the formation and use of the preconditioner.
> Just make sure that the domain and range maps of the preconditioner are
> compatible with the data distribution of the original problem.  If you
> decide this is a route to take, I can point you to some examples.  Since the
> preconditioner is the only phase whose robustness is affected by data
> distribution, this is an effective way of addressing this problem.

Agreed. Can you please point to good starting points?


> This technique also works for Amesos (see next).

I overlooked Amesos. I thought that Aztec was the only solver interface
(maybe because it has more puplicity?). I can see now that there are
several solver packages. I'll start learning more about how to use Amesos.


> Finally, if the target problem for this solve is fairly small, a direct
> solver is probably best.  There are a number of parallel direct solvers
> available via the Trilinos package Amesos.  Amesos provides a consistent
> interface to many of the popular direct sparse solvers, including UMFPACK,
> SuperLU (serial and distributed), DSCPACK and other.  Amesos is quite easy
> to use, however all solvers except KLU must be built independently from
> Trilinos since they are 3rd-party software.

The web page says that KLU is a serial direct solver, so I assume that
I cannot use it in my parallel program if I'm running on more than one
node. 9 other solvers are listed. Can you recommend one of them at this
time so I can ask our cluster admin to install? Perhaps the one that is
most commonly used in the HPC community. Would be nice if there is a
comparison grid to help choosing.

Thank you for your continous help.


-ammar