[petsc-users] Nullspaces for schur complement PCs

[Jed Brown]

Dmitry Karpeyev <karpeev at mcs.anl.gov> writes:

> I think the problem-specific solver configuration can be carried out by an
> additional user-specified callback (attached, e.g., using PCSetUserSetUp())
> called from PCSetUp().
> The problem of propagating it down the hierarchy can be solved by using DMs
> (even DMShell would do, as it carries an ApplicationCtx) and a consistent
> use of DMFieldSplitRestrictHook (by analogy with other restriction hooks,
> like DMSubDomainRestrictHook).  DMFieldSplitRestrict() would be called when
> creating each split and one of the restriction hooks would transfer the
> necessary contexts.
>
> This is a bit heavyweight, but flexible and logically consistent, it seems
> to me, and no worse that what has to be done to propagate things like
> DMSNES/DMKSP through the MG hierarchy. (N)ASM uses something similar, too.

Previously discussed.

http://lists.mcs.anl.gov/pipermail/petsc-dev/2012-August/009291.html

It makes things more dependent on DM, but that may be less bad than the
alternatives.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 818 bytes
Desc: not available
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20141113/837afb41/attachment-0001.pgp>