[Trilinos-Users] Solvers and preconditioners available for Epetra_VbrMatrices

Charles Boivin charles.boivin at mayahtt.com
Fri Sep 16 10:02:52 MDT 2011


Mike,

This last comment regarding preconditioners is puzzling me a bit. We've recently started using an Epetra_VbrMatrix (actually Epetra_FEVbrMatrix) in our code, and are feeding it to the ML preconditioner. Now, from what you are saying, this should not be working...

How does that manifest itself exactly? Would it crash? Give the wrong answer? Or simply not be as efficient as it should?

We've been able to get answers out of this setup... 

Thank you,

Charles Boivin

-----Original Message-----
From: trilinos-users-bounces at software.sandia.gov [mailto:trilinos-users-bounces at software.sandia.gov] On Behalf Of Heroux, Michael A
Sent: Thursday, September 15, 2011 3:04 PM
To: Alberto F. Martín-Huertas; trilinos-users at software.sandia.gov
Cc: Javier Principe
Subject: Re: [Trilinos-Users] Solvers and preconditioners available for Epetra_VbrMatrices

Alberto,

All of the solvers and preconditioners in Trilinos are usable with
Epetra_VbrMatrix objects.

The iterative solvers will use your VbrMatrix directly and utilize the block
structure.

However, there are no block entry preconditioners.  All of the
preconditioners will be constructed as point entry objects.  In fact,
because of a structural deficiency in Epetra_VbrMatrix, you will need to
construct an Epetra_VbrRowMatrix object (which is a light-weight wrapper
around Epetra_VbrMatrix) and pass that to the preconditioner.  It's a single
line of code, but is required for proper interpretation of the
Epetra_RowMatrix interface with a VbrMatrix object.

I hope this helps.

Mike


On 9/15/11 1:04 PM, "Alberto F. Martín-Huertas" <amartin at cimne.upc.edu>
wrote:

>  Dear Trilinos-Users,

 is there any reference where I can
 find which krylov
> subspace solvers (AztecOO)
 and preconditioners (ML, Ifpack, AztecOO) are
> available
 for variable block row distributed matrices
 (i.e.,
> EpetraVbrMatrix).

 Thanks in advance.

 Best regards,
  Alberto.


-- 

> Alberto F. Martín-Huertas
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> l'Enginyeria (CIMNE)
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> 5, Building C3, Office 210,
 08860 Castelldefels (Barcelona, Spain)
 Tel.:
> (+34) 9341 34223
 e-mail: amartin at cimne.upc.edu

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