[Dune] Local node numbering in Dune

[Jö Fahlke]

Am Fri, 10. Apr 2015, 14:09:09 +0100 schrieb Ganesh Diwan:
> Date: Fri, 10 Apr 2015 14:09:09 +0100
> From: Ganesh Diwan <gcdiwan83 at gmail.com>
> To: Oliver Sander <sander at igpm.rwth-aachen.de>, DUNE Liste
>  <dune at dune-project.org>
> Subject: Re: [Dune] Local node numbering in Dune
> X-No-Auth: unauthenticated sender
> X-No-Relay: not in my network
> X-Envelope-From: <gcdiwan83 at gmail.com>
> 
> Hi Oliver
> 
> When I loop through the element(s), I see that Dune returns element faces
> that are in conflict with what the link above says. To be specific I get
> my face 2 as Dune reference element face 0,
> my face 0 as Dune reference element face 1,
> my face 3 as Dune reference element face 2,  and
> my face 1 as Dune reference element face 3,
> 
> Clearly I am doing something wrong!

I'm sorry, you appear to have included the wrong version of MeshTraversal in
your mail.  At least I cannot see how it could have produced the output above,
since it does not contain the string "my face".

(In case I misunderstood and MeshTraversal was not meant to produce that
output, please clarify how you obtained the numbers after "my face" and "Dune
reference element face".)

Regards,
Jö.

> I have:
> 
> typedef Dune::ALUGrid<2, 2, Dune::cube, Dune::nonconforming> GridTypeALU;
> std::auto_ptr<GridTypeALU> mygrid( GmshReader<GridTypeALU>::read(
> "./grids/hhgex.msh", true, true ) );
> MeshTraversal (*mygrid); //
> 
> and then I have MeshTraversal as:
> 
> template<class G>
> void MeshTraversal(G& grid) {
>     //first we extract the dimensions of the grid
> 
>     const int dim = G::dimension;
>     std::cout << "dimension of the grid is: " << dim << std::endl;
>     const int dimworld = G::dimensionworld;
>     typedef typename G::ctype ct;
>     typedef typename G::LeafGridView GridView;
> 
>     typedef typename GridView::template Codim<0>::Iterator LeafIterator;
>     typedef typename GridView::IntersectionIterator IntersectionIterator;
> 
>     GridView gridView = grid.leafView();
>     // get grid view on leaf part
> 
>     LeafIterator endit = gridView.template end<0>();
> 
>     int count = 0;
>     //
>     for (LeafIterator it = gridView.template begin<0>(); it != endit; ++it)
> {
> 
>         count++;
>         Dune::GeometryType gt = it->type();
>         //
>         std::cout << "visiting element " << count << gt << std::endl;
> 
>         IntersectionIterator isend = gridView.iend(*it);
> 
>         int countface = 0;
>         for (IntersectionIterator is = gridView.ibegin(*it); is != isend;
>                 ++is) {
>             countface++;
>             Dune::GeometryType gfacet = is->type();
>             std::cout << "visiting face " << countface << gfacet <<
> std::endl;
>             std::cout << "node 1 for face" << countface << " is "
>                     << is->geometry().corner(0) << std::endl;
>             std::cout << "node 2 for face" << countface << " is "
>                     << is->geometry().corner(1) << std::endl;
>             //
>         }
>     }
>     std::cin.get();
> }
> 
> 
> 
> On Wed, Apr 8, 2015 at 3:57 PM, Ganesh Diwan <gcdiwan83 at gmail.com> wrote:
> 
> > Thankyou!
> >
> > Ganesh
> >
> > On Wed, Apr 8, 2015 at 3:56 PM, Oliver Sander <sander at igpm.rwth-aachen.de>
> > wrote:
> >
> >> Am 08.04.2015 um 16:50 schrieb Ganesh Diwan:
> >> > Dear List
> >> >
> >> > It appears that after reading the grid from a Gmsh format file inside
> >> Dune,
> >> > the local dofs 2 and 3 i.e. node number 3 and 4 are swapped. This is
> >> inside
> >> > dune-grid//dune/grid/io/file/gmshreader.hh
> >> >
> >> > Is there a specific reason this is done? Is there a way to tell Dune to
> >> use
> >> > the same node numbering as in Gmsh file and not to alter it?
> >>
> >> Hi Ganesh,
> >> Dune has one fixed numbering for the local node numbers of all reference
> >> elements
> >> (see
> >> http://www.dune-project.org/doc/doxygen/dune-geometry-html/group___geometry_reference_elements.html
> >> )
> >>
> >> These numberings differ from the ones used by gmsh, and hence the gmsh
> >> reader
> >> needs to do some node swapping.
> >>
> >> Best,
> >> Oliver
> >>
> >> >
> >> > Thankyou
> >> > Ganesh
> >> >
> >> >
> >> >
> >> > _______________________________________________
> >> > Dune mailing list
> >> > Dune at dune-project.org
> >> > http://lists.dune-project.org/mailman/listinfo/dune
> >> >
> >>
> >>
> >>
> >> _______________________________________________
> >> Dune mailing list
> >> Dune at dune-project.org
> >> http://lists.dune-project.org/mailman/listinfo/dune
> >>
> >>
> >

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-- 
Jorrit (Jö) Fahlke, Institute for Computational und Applied Mathematics,
University of Münster, Orleans-Ring 10, D-48149 Münster
Tel: +49 251 83 35146 Fax: +49 251 83 32729

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