[Trilinos-Users] Problems with crashing with the ML's MatrixFreePreconditioner (UNCLASSIFIED)

[Ramsey, James J CIV (US)]

Classification: UNCLASSIFIED
Caveats: NONE

-----Original Message-----
I've tried two different types of Epetra_CrsGraph with the 
MatrixFreePreconditioner: one like that used to construct the 
Epetra_CrsMatrix, and one like that used to construct the Epetra_FEVbrMatrix 
(with a block size of 3).
-----End Original Message-----

Okay, I've tried a new graph, which seems to work, at least in the sense of 
not crashing and of returning the same results that I get when not using the 
preconditioner. What I did was to create a graph *without* applying the 
boundary conditions that I apply when creating the graph for the 
Epetra_FEVbrMatrix.

However, performance isn't particularly better than not using a 
preconditioner. I've got far fewer *iterations* (~50 iterations with ML vs. 
~300 without), but each iteration takes longer. Currently, I'm using the 
Chebyshev smoother and "METIS" as the aggregation type. The other parameters 
are left at their defaults.

Classification: UNCLASSIFIED
Caveats: NONE


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