[petsc-users] [petsc-maint] How to impose boundary conditions using DMDA

[Matthew Knepley]

On Sun, Oct 28, 2018 at 12:18 PM Smith, Barry F. <bsmith at mcs.anl.gov> wrote

>     Matt,
>
>        How difficult would it be to impose such boundary conditions with
> DMPlex? Presumably you just connect the mesh up "properly" and it is
> straightforward?
>

If you figure out what topology is meant by this, it should not be hard.
However, I
cannot figure out what they mean right now.

  Thanks,

    Matt


>    Barry
>
>
> > On Oct 27, 2018, at 10:23 AM, Matthew Knepley <knepley at gmail.com> wrote:
> >
> > On Sat, Oct 27, 2018 at 2:02 AM Fengwen Wang <fwan at mek.dtu.dk> wrote:
> > Dear Colleagues,
> >
> >
> >
> > I use the finite element method to solve my problem in Petsc.
> >
> >
> >
> > Mesh is defined as a  regular mesh using DMDA.  I have a special
> boundary condition which I  do not know how to impose it in Petsc.
> >
> >
> >
> > In a 2D problem, the domain is unit size, two degrees of freedom per
> node (u, v). I would like impose the following boundary condition:
> >
> >
> >
> > u(x=1) = -v ( y=1) and v(x=1 )= -u (y=1) .
> >
> >
> >
> > How can I impose such a boundary condition in Petsc?
> >
> > In a serial code, you could do this just by equating those variables,
> but in parallel we have no support for such a boundary condition.
> >
> >   Thanks,
> >
> >      Matt
> > Thanks a lot.
> >
> >
> >
> > Best regards
> >
> > Fengwen
> >
> >
> >
> >
> >
> > ____________________________________________________
> > Senior Researcher
> > Department of Mechanical Engineering, DTU
> > Nils Koppels Allé
> > Building 404
> > 2800  Kgs. Lyngby
> > fwan at mek.dtu.dk
> >
> >
> > --
> > 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/
>
>

-- 
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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