Re: dof with singular mesh

[Yves Renard]

Dear Edouard,

I tested with the Matlab interface a similar experience :

tmesh = gf_mesh('load', 'savemesh.mesh')
tmeshfem = gf_mesh_fem(tmesh, 1)
gf_mesh_fem_set(tmeshfem, 'fem', gf_fem('FEM_PK(2, 4)'))
pdof = gf_mesh_fem_get(tmeshfem, 'basic dof nodes');
gf_plot_mesh(tmesh);
hold on; scatter(pdof(1,:), pdof(2,:), '+'); hold off
And I do not have the problem (see attached image of the small circle)

I do not see where your result comes from.

Best regards,

Yves







Le 11/05/2021 à 17:57, Edouard Oudet a écrit :
> oups, sorry
>
> https://www-ljk.imag.fr/membres/Edouard.Oudet/download/dof_singular.png
>
> Best
>
> On 5/11/21 5:46 PM, Yves Renard wrote:
> > Dear Edouard,
> >
> > Your second picture is missing. Can you send the link again ?
> >
> > Best regards,
> >
> > Yves
> >
> >
> > Le 11/05/2021 à 16:11, Edouard Oudet a écrit :
> > > Dear getfem users,
> > >
> > > Using the python interface of Getfem++, I obtained surprising 
> > > results related to the representation of degrees of freedom for a 
> > > singular mesh associated to a square with two circular holes. One of 
> > > the hole has a very small radius see picture
> > >
> > > https://www-ljk.imag.fr/membres/Edouard.Oudet/download/singmesh.png
> > >
> > > This mesh can be downloaded at
> > >
> > > https://www-ljk.imag.fr/membres/Edouard.Oudet/download/savemesh.mesh
> > >
> > > Using the following instructions
> > >
> > > filemesh = '/tmp/savemesh.mesh'
> > > tmesh = getfem.Mesh("load", filemesh)
> > > tmeshfem = getfem.MeshFem(tmesh, 1)
> > > tmeshfem.set_fem(getfem.Fem('FEM_PK(2, 4)'))
> > > pdof = getfem.MeshFem.get(tmeshfem, 'basic dof nodes')
> > >
> > > and plotting these pdof points I obtained the following picture 
> > > around the small circle
> > >
> > > https://www-ljk.imag.fr/membres/Edouard.Oudet/download/savemesh.mesh
> > >
> > > As it can be observed some dof are missing.. I do not get this 
> > > problem for a degree smaller than 4.
> > > Any suggestions are welcome,
> > >
> > > best,
> > >
> > > Edouard.

--

  Yves Renard (Yves.Renard@insa-lyon.fr)       tel : (33) 04.72.43.87.08
  INSA-Lyon
  20, rue Albert Einstein
  69621 Villeurbanne Cedex, FRANCE
  http://math.univ-lyon1.fr/~renard

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mesh.jpg
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