[Trilinos-Users] Sparse direct solver and language options for GPU

[Tom Anderson]

Alicia,

Yes, please send this to me. There is so much in the Benzi/Golub paper that
I didn't know where to begin, and it is great to hear about your approach.
I am especially interested to see you computed AZ=B. In my case, A and B
are both sparse.

I haven't yet figured out how to use preconditioning in my system.
I tried ML but so far I just get segfaults. I hope to learn from your
example.

Thanks,

-Tom Anderson
tomacorp at gmail.com

From: Alicia M Klinvex <aklinvex at purdue.edu>

I have a few Trilinos codes that solve saddle point problems of a specific
structure: the 1-1 block is a sparse, symmetric matrix (A); the 1-2 block
is a multivector (a tall, dense matrix) (B); the 2-1 block is B^T; the 2-2
block is zero.

The first code I have forms the inexact Schur complement S=B^T Z, where Z
is the approximate solution of AZ=B, computed by an iterative method.  (If
you want to precondition A, you can.  If you want to use a direct method
instead of an iterative one, you could also do that.)  It then uses the
Schur complement to construct the solution to your saddle point problem (as
in section 5 of the Benzi/Golub paper).

I also implemented the block diagonal preconditioner of section 10.1.1.  I
haven't implemented block upper triangular preconditioning, constraint
preconditioning or any of the other block preconditioners they mention, but
it wouldn't be too difficult to modify the code to accommodate them.

These saddle point solvers aren't in Trilinos 11.10.2 (as far as I know),
but I'd be happy to send you my code if it would help you.

Best wishes,
Alicia
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://software.sandia.gov/pipermail/trilinos-users/attachments/20140921/08eefbaf/attachment.html>