[petsc-users] How can I retrieve the IS for all Missing Diagonal entries?

[Smith, Barry F.]

> On Nov 22, 2017, at 10:13 AM, Eric Chamberland <Eric.Chamberland at giref.ulaval.ca> wrote:
> 
> Hi,
> 
> I have 2 questions:
> 
> First, I am looking for a function that is almost like MatMissingDiagonal, but that would return me *all* missing diagonal entries.
> 
> Does it exists?

  I'm afraid not.

> 
> If not, is there another way of doing this?

  You would have to copy the appropriate MatMissingDiagonal_SeqAIJ() code and modify for your needs.

  Barry

> 
> Second: after searching through Petsc list, I found this that upset me a bit:
> 
> https://www.mail-archive.com/petsc-users@mcs.anl.gov/msg22867.html
> 
> so maybe I should modify our code to be fully compliant with this?  I have some examples (MUMPS) that are working without diagonal entries but I didn't tried other PCs or KSPs...
> 
> Thanks,
> 
> Eric