[petsc-dev] LSC question

[Jed Brown]

On Thu, Mar 8, 2012 at 15:40, Barry Smith <bsmith at mcs.anl.gov> wrote:

> But the LSC_L reflects properties of the true operator while LSC_Lp
> reflects properties of the matrix from which you build the preconditioner.
>

Only if you used -pc_fieldsplit_real_diagonal. My concern is that pc->mat
is a MatSchurComplement that is not likely to be made by the user (the user
never has access to it in PCFieldSplit so there is no way it can be
anything else). If we actually used the MatGetSchurComplement() interface,
the user would have an opportunity to see it, but it's not practical to do
that currently because it would duplicate the submatrices.


> Hence LSC_L should be attached to pc->mat
>
>  So why not check in pc->mat first and if not there check in pc->pmat
>
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