[petsc-users] snes ex12 question about DMPlexProjectFunctionLocal

[Matthew Knepley]

On Thu, Nov 14, 2013 at 8:16 PM, Geoffrey Irving <irving at naml.us> wrote:

> On Thu, Nov 14, 2013 at 6:08 PM, Matthew Knepley <knepley at gmail.com>
> wrote:
> > On Thu, Nov 14, 2013 at 7:38 PM, Geoffrey Irving <irving at naml.us> wrote:
> >>
> >> On Thu, Nov 14, 2013 at 5:35 PM, Matthew Knepley <knepley at gmail.com>
> >> wrote:
> >> > On Thu, Nov 14, 2013 at 7:32 PM, Geoffrey Irving <irving at naml.us>
> wrote:
> >> >>
> >> >> If this line in ex12 is part of Dirichlet boundary conditions, why is
> >> >> it done unconditionally even for Neumann?  Is this a mistake that
> >> >> fails to test correct Neumann conditions?
> >> >>
> >> >>     ierr = DMPlexProjectFunctionLocal(dm, user.fe, user.exactFuncs,
> >> >> INSERT_BC_VALUES, userJ.u);CHKERRQ(ierr);
> >> >
> >> > No, its just idempotent in that case.
> >>
> >> That's what I meant by fail to test: if there was a bug related to
> >> null spaces, it wouldn't show up in this example.
> >
> >
> > I do not understand. If you have Neumann conditions, nothing happens, so
> > it would check that case.
>
> I may be misunderstanding something, but wouldn't nothing happen only
> if the rest of the code is correct?


Nothing would happen as long as you have not set any Dirichlet conditions.

   Matt


> Geoffrey
>



-- 
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
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