[petsc-users] DMPlexCreateGmsh

[Matthew Knepley]

On Thu, Jan 16, 2014 at 2:17 PM, Dharmendar Reddy
<dharmareddy84 at gmail.com>wrote:

> Hello,
>         Gmsh does not output mesh in exodus format. I tried hard to
> look for an open source mesher which i can use, i ended up with gmsh.
> If there is a better alternative i can switch.
>

You could use --download-ctetgen which also meshes in 3D. I am not sure
what else Gmsh provides.


> Currently i pre process the gmsh file in my fortran code before i
> create a dm object via createFromCellList.
>
> Is there an opensource mesh converter available which can take gmsh to
> exoduss, i could not find one. I tried writing one but the problem is,
> i have to first form all the edges/facets in the mesh and map them to
> the boundary before i can create the sidesets for the exodus.
>

This at least is easy. If you have a cell-vertex mesh, you can call

  DMPlexInterpolate(dm, &idm);

and get the edges/faces.


> So, if it is possible, i will prefer to read my mesh via
> DMPLexcreateGmsh otherwise i can continue to use my code.
>

We can try. What will probably happen is that the reader will be able to
handle
exactly what you need since the full format is a little crazy.

  Thanks,

      Matt


> Thank you All
> Reddy
>
>
> On Thu, Jan 16, 2014 at 8:28 AM, Jed Brown <jed at jedbrown.org> wrote:
> > Matthew Knepley <knepley at gmail.com> writes:
> >
> >> On Sun, Jan 12, 2014 at 7:37 PM, Gorman, Gerard J
> >> <g.gorman at imperial.ac.uk>wrote:
> >>
> >>>  Hi Matt
> >>>
> >>>  First - really sorry for having inflicted this on you. I agree that
> >>> there are many problems with the format and it’s not like the world
> needs a
> >>> new file format. I only happened to use it for a case where there was
> an
> >>> existing toolchain…which I’m now rewriting anyhow.
> >>>
> >>>  What is your current least detested file format for FEM that plays
> >>> nicely with DMPlex? Exodus II?
> >>>
> >>
> >> ExodusII we can read, and it maintains all the markers correctly, etc.
> It
> >> is currently my favorite.
> >
> > CGNS is another alternative that is implemented (though less mature in
> > PETSc).  Note that CGNS is more typically finite volume CFD oriented,
> > though it can also be used for FEM.
>
>
>
> --
> -----------------------------------------------------
>



-- 
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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