[petsc-users] dmplex normal vector incorrect for periodic gmsh grids

[Matthew Knepley]

On Tue, Dec 13, 2022 at 6:11 AM Praveen C <praveen at gmx.net> wrote:

> Hello
>
> In the attached test, I read a small grid made in gmsh with periodic bc.
>
> This is a 2d mesh.
>
> The cell numbers are shown in the figure.
>
> All faces have length = 2.5
>
> But using PetscFVFaceGeom I am getting length of 7.5 for some faces. E.g.,
>
> face: 59, centroid = 3.750000, 2.500000, normal = 0.000000, -7.500000
>
> ===> Face length incorrect = 7.500000, should be 2.5
>
> support[0] = 11, cent = 8.750000, 3.750000, area = 6.250000
>
> support[1] = 15, cent = 8.750000, 1.250000, area = 6.250000
>
>
> There are also errors in the orientation of normal.
>
> If we disable periodicity in geo file, this error goes away.
>

Yes, by default we only localize coordinates for cells. I can put in code
to localize faces.

  Thanks,

    Matt


> Thanks
> praveen
>
-- 
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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