[petsc-dev] Lies in PCFieldSplit

[Matthew Knepley]

On Sun, Dec 2, 2012 at 10:57 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:
>
>   Jed, Matt, or I are responsible for what are likely lies in the field split naming terminology
>
>    We have
>
> const char *const PCFieldSplitSchurPreTypes[] = {"SELF","DIAG","USER","PCFieldSplitSchurPreType","PC_FIELDSPLIT_SCHUR_PRE_",0};
>
> Diag here actually means the A11 matrix, correct?
>
>     case PC_FIELDSPLIT_SCHUR_PRE_DIAG:
>       ierr = PetscViewerASCIIPrintf(viewer,"  Preconditioner for the Schur complement formed from the block diagonal part of A11\n");CHKERRQ(ierr);break;
>     case PC_FIELDSPLIT_SCHUR_PRE_USER:
>       if (jac->schur_user) {
>
> block diagonal part of A11 actually means A11, correct?  Otherwise what blocks????

Processor diagonal. This is not ASM where what we select is
automatically process diagonal.

   Matt

>    Once I get confirmation that these are phrased wrong I will update the source to be less confusing. Otherwise please example what diagonal means and how it is used here.
>
>     Thanks
>
>    Barry
>



--
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which
their experiments lead.
-- Norbert Wiener