getfem-users
[Top][All Lists]

## Re: dof with singular mesh

 From: Yves Renard Subject: Re: dof with singular mesh Date: Tue, 11 May 2021 19:38:55 +0200 User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1

```
Dear Edouard,

I tested with the Matlab interface a similar experience :

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

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
```

Using the following instructions

filemesh = '/tmp/savemesh.mesh'
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
```

```
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

---------

```

mesh.jpg
Description: JPEG image