[aspect-devel] Direct Solver in Aspect

[Timo Heister]

(cc'ed to the mailing list)

> Before I change anything about the system matrix, I'd like the ability
> to use a direct solver so I can test my changes on a simple 2d mesh
> and not worry about preconditioners for the time being.

I am working on it as we speak:
https://github.com/tjhei/aspect/tree/direct_solver


> If I understand the documentation, this basically just means using an
> object of type TrilinosWrappers::SolverDirect::SolverDirect rather
> than SolverFGMRES<LinearAlgebra::BlockVector> and replacing the
> distributed LinearAlgebra::BlockVector arguments with SparseMatrix and
> Vector types from the TrilinosWrappers namespace. Is this correct, or
> is there a better way to do this?

We need to:
1. put velocity and pressure into a single block (done)
2. fix all the places that assume the current layout (say T is in block 3)
3. Apply SolverDirect to the 0,0 block.

I am working on 2), while 1&3 is done.

-- 
Timo Heister
http://www.math.clemson.edu/~heister/