[Trilinos-Users] Behavior of Epetra_VbrMatrix and Epetra_MultiVector

Bill McGrory mcgrory at aerosoftinc.com
Fri Dec 28 08:24:46 MST 2012

I'm confused about the use/behavior of Epetra_VbrMatrix and 

I am trying to port a legacy CFD software package to use Trilinos. I 
have internal iterative sparse solvers which I can compare against.

I am solving a coupled system of equations (let's just say 5 for now, 
(mass, 3x momentum and energy)
So I thought I would put fill a VbrMatrix where each block was the 
Jacobian of the local system (dF/dQ_i) 5x5 blocks
and I filled my MultiVector over the number of control volumes, x 5 
where the 5 was each equation I am solving

I'm Implicit Newton iterations for time integration, so I need to solve 
an A dQ = -R type system, and I'm using Belos.

This fails to reproduce my behavior of the legacy code, so I step back 
and tried to fill my A with  diagonal dense blocks, and 0 off diagonals, 
and when I solve this embarrassingly simple problem I get a solution 
that is only dependent on the 1,1 entry of the dense block, which tells 
me I'm not interpreting the use of VbrMatrix and MultiVector correctly?

What am I doing wrong?

I'd hate to think that I have to fill each term in a CrsMatrix


Dr. William D. McGrory    AeroSoft, Inc.
mcgrory at aerosoftinc.com   Suite 1400
(540) 557-1904            2000 Kraft Drive
(540) 557-1919 (FAX)      Blacksburg, VA 24060

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