[petsc-dev] DD FAQ

[Jed Brown]

The FAQ mentions PCNN, but the advice "-pc_type nn" is completely
inadequate to actually use this method, and the referenced example does
not exist.  I have removed it's mention from the "Domain Decomposition"
answer, I think it needs a working example in order to be mentioned
there.  Also, ex2 -pc_type nn -mat_type fails with a seg-fault, I
haven't investigated why.

Barry, PCEXOTIC does have a working example, should it be mentioned
here, or do you consider it to be a toy that users needn't bother trying
to use.

As for future DD directions, have you thought about what is necessary to
provide quasi-generic support for optimized Schwarz.  I was only vaguely
aware of this method until recently, but this approach seems to offer
significant potential, especially for some indefinite problems.

Jed