[aspect-devel] Direct Solver in Aspect

[Wolfgang Bangerth]

>> How difficult would it be to extend TrilinosWrappers::SolverDirect?
>
> It can not possibly work with a 2x2 table of Trilinos matrices. The
> only option I see would be to copy everything from a block matrix into
> a single matrix. I don't think this is a good solution.

Oh, yes, I hadn't remembered that we already store data as Trilinos matrices, 
so we don't have access to individual elements. That's the difference to the 
UMFPACK interface, of course.


> I only need an if in very few places so far. It mostly involves
> replacing things like
>
>    IndexSet range = this->get_solution().block(2).locally_owned_elements();
>
> by
>
>    const unsigned int blockidx = this->introspection().block_indices.temperature;
>    IndexSet range =
> this->get_solution().block(blockidx).locally_owned_elements();
>
> which is useful anyway.

Yes, absolutely.


>> Anyway, good feature. I'm looking forward to seeing how it works in practice
>> :-)
>
> One of the things that I got out of the CIG MC meeting that might help
> with the speed for large 2d computations on a single workstation.
> We'll see.

Does it work in parallel?

W.


-- 
------------------------------------------------------------------------
Wolfgang Bangerth               email:            bangerth at math.tamu.edu
                                 www: http://www.math.tamu.edu/~bangerth/