[petsc-dev] circular dependencies SLEPc

[Matthew Knepley]

On Wed, Jun 26, 2019 at 4:11 PM Jed Brown <jed at jedbrown.org> wrote:

> Matthew Knepley <knepley at gmail.com> writes:
>
> > On Wed, Jun 26, 2019 at 3:42 PM Jed Brown via petsc-dev <
> > petsc-dev at mcs.anl.gov> wrote:
> >
> >> "Smith, Barry F." <bsmith at mcs.anl.gov> writes:
> >>
> >> >> On Jun 26, 2019, at 1:53 PM, Jed Brown <jed at jedbrown.org> wrote:
> >> >>
> >> >> "Smith, Barry F." <bsmith at mcs.anl.gov> writes:
> >> >>
> >> >>>  It is still a PC, it may as part of its computation solve an
> >> eigenvalue problem but its use is as a PC, hence does not belong in
> SLEPc.
> >> >>
> >> >> Fine; it does not belong in src/ksp/pc/.
> >> >
> >> >   Why not? From the code mangement point of view that is the perfect
> >> place for it. It just depends on an external package in the same way
> that
> >> PCHYPRE depends on an external library. Having it off in some other
> >> directory src/plugins would serve no purpose. Of course making sure it
> >> doesn't get compiled into -lpetsc may require a tweak to the make
> >> infrastructure. Make could, for example, skip plugin subdirectories for
> >> example.
> >>
> >> I think it's confusing to have code that is part of libpetsc.so
> >> alongside code that is not (e.g., won't be accessible to users unless
> >> they also build SLEPc and link the plugin).
> >>
> >> >   BTW: Matt's perverse use of SNES from DMPLEx could also be fixed to
> >> >   work this way instead of the disgusting PetscObject casting used to
> >> >   cancel the SNES object.
> >>
> >> That code could be part of libpetscsnes.so.
> >>
> >
> > What? I thought I moved everything to SNES a long time ago.
>
> I thought there was a place where SNES was cast to PetscObject.  There
> is DMAddField, but it's different.
>

I can't find it right now. Yeah, AddField is waiting for a true
Discretization object.
I think its spelled G-O-D-O-T.


> PetscViewerVTKAddField is another example of code that uses PetscObject
> to avoid depending on a higher level type like Vec.
>

Viewer is a weird mixin with everything.

   Matt

-- 
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

https://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/>
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