[Trilinos-Users] Assembling inverses of sub matrices

[Hoemmen, Mark]

On 11/5/16, 4:38 PM, "Trilinos-Users on behalf of trilinos-users-request at trilinos.org" <trilinos-users-bounces at trilinos.org on behalf of trilinos-users-request at trilinos.org> wrote:
>Date: Thu, 3 Nov 2016 19:36:59 +0100
>From: Karim Khayrat <kkhayrat at gmail.com>
>To: trilinos-users at trilinos.org
>Subject: [Trilinos-Users] Assembling inverses of submatrices
>
>I was wondering what is the best approach in Trilinos to take the following
>problem.
>
>Given a matrix A, I want to extract submatrices, invert them and reassemble
>them. This is very similar to what is done to obtain the schwarz
>preconditioner
>(see https://trilinos.org/oldsite/packages/ifpack/IfpackUserGuide.pdf
>equation 17). However I want to specify the subdomains myself since I will
>generally have much more subdomains than processors.

Ifpack_BlockRelaxation can do what you want.  I’m not an Ifpack developer, but we are currently refactoring Ifpack2::BlockRelaxation, which implements similar functionality.

mfh