A different kind of lagged preconditioner

Mon Mar 23 14:06:07 CDT 2009

Barry,

sorry if I'm coming off stubborn or something, but I think I'm not following
your reasoning.

 NO.
>
>  If you are using LU to construct a preconditioner then you ARE providing
> the Jacobian explicitly (as a sparse) matrix.  Each time the preconditioner
> is built this sparse matrix is factored.

What do you mean by "providing the jacobian explicity (as a sparse) matrix"?
I thought that there was no explicit jacobian matrix, but only a MATMFFD
context.

Rafael
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