[Trilinos-Users] [EXTERNAL] ilut

Danielle Catherine Maddix dcmaddix at stanford.edu
Fri Jan 22 13:48:00 EST 2016

Hi Andrew,

Thanks for the help!

1. With no preconditioner, 1,2,3 and 4 processors and no preconditioner, I get the same answer.  It does not converge to the correct solution due to ill-conditioning. but is consistent amongst the processors.

2. Yes, the 12,4-proc cases all give the same correct solution with the ilut preconditioner.

Let me know what you think.


From: Bradley, Andrew Michael <ambradl at sandia.gov>
Sent: Friday, January 22, 2016 10:24 AM
To: Danielle Catherine Maddix; trilinos-users at trilinos.org
Subject: Re: [EXTERNAL] [Trilinos-Users] ilut

Hi Danielle,

1. What happens if you do not use a preconditioner at all?

2. Have you verified in the 1,2,4-proc cases that the output solutions all agree?



From: Trilinos-Users <trilinos-users-bounces at trilinos.org> on behalf of Danielle Catherine Maddix <dcmaddix at stanford.edu>
Sent: Friday, January 22, 2016 11:20 AM
To: trilinos-users at trilinos.org
Subject: [EXTERNAL] [Trilinos-Users] ilut


I am solving a FSI finite element matrix vector system.  I am using GMRES with glut in AztecOO.  It appropriately solves it for 1,2 and 4 processors on my local machine, which with 3 processors it cannot bring the residual down below 1e-1.  I was wondering if this could be an issue with the ilut preconditioner, since it says convergence depends on the domain decomposition, or if it is possible there is a bug in my code?


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