[Trilinos-Users] direct invertion of a projected matrix (Amesos and Epetra_CrsMatrix?)

[Heroux, Michael A]

?*Performance will be quite poor, I think.

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From: Trilinos-Users <trilinos-users-bounces at trilinos.org> on behalf of Heroux, Michael A <maherou at sandia.gov>
Sent: Tuesday, March 21, 2017 6:43 PM
To: Denis Davydov; trilinos-users
Subject: [EXTERNAL] Re: [Trilinos-Users] direct invertion of a projected matrix (Amesos and Epetra_CrsMatrix?)


Denis,


You can store a full matrix as a Epetra_CrsMatrix and use Amesos.  Performance will be quite, I think.?


Can you give more details about the dimensions of the problems?


Also, are you using an optimized BLAS for your LAPACK computations?


Mike


________________________________
From: Trilinos-Users <trilinos-users-bounces at trilinos.org> on behalf of Denis Davydov <davydden at gmail.com>
Sent: Tuesday, March 21, 2017 9:38 AM
To: trilinos-users
Subject: [EXTERNAL] [Trilinos-Users] direct invertion of a projected matrix (Amesos and Epetra_CrsMatrix?)

Dear all,

I would like to have a MPI-parallel inversion of (eventually sparse) matrix of size N being several hundreds.
I put "sparse" in brackets, because for starters i need to consider it full. The matrix represents the
projection of a FE operator on a vector subspace. I guess something similar is probably done in
Anasazi in the context of eigensolvers.

So the main question is if I can use Epetra_CrsMatrix but for now set the sparsity to be full?
If that is possible, i suppose i should be able to use Amesos direct solvers to get LU factorization
of the matrix (say using ScaLAPACK) and then do whatever I want with it.

If there are other classes in Trilinos to do the job better, please let me know.

p.s. currently i do inversion in serial, eventually using Lapack, but this takes too much time.

Sincerely,
Denis.

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