Re: [Getfem-users] Problem with mixed meshes

[Yves Renard]

Dear Phuoc,

The problem come from the fact that the test is made on the mean unit 
normal vector on a face. This mean unit normal vector is computed by 
averaging the unit normal vector on each geometrical node of a face. 
Unfortunately, for a pyramid element, the transformation is singular on 
the geometrical nodes.

I replaced the mean of normal vector by the normal vector on the mean of 
geometrical nodes of the face. It fixes the problem.  (I push the change 
on the master branch).

Best regards,

Yves


Le 14/06/2018 à 15:40, Huu Phuoc BUI a écrit :
> Dear Yves,
>
> Please find the mesh attached.
>
> Thank you for your help.
>
> Best regards,
>
> Phuoc
>
>
> On 14/06/2018 14:52, Yves Renard wrote:
> > Dear Phuoc,
> >
> > No, I see no reason. If you can just send me the mesh in a format 
> > readable by GetFEM, I could check what is wrong.
> >
> > Best regards,
> >
> > Yves
> >
> > Le 14/06/2018 à 10:24, Huu Phuoc BUI a écrit :
> > > Dear Getfem-users,
> > >
> > > I have a problem with computing the outer faces when using a mixed 
> > > mesh (having tetras, hexa, prisms and pyramids).
> > >
> > > The error is:
> > >
> > > face_left = m.outer_faces_with_direction([0, 0., -1.0], 0.01)
> > >   File "/usr/local/lib/python2.7/dist-packages/getfem/getfem.py", 
> > > line 1372, in outer_faces_with_direction
> > >     return self.get("outer_faces_with_direction", v, angle, CVIDs)
> > >   File "/usr/local/lib/python2.7/dist-packages/getfem/getfem.py", 
> > > line 1152, in get
> > >     return getfem('mesh_get',self.id, *args)
> > > RuntimeError: (Getfem::InterfaceError) -- Error in 
> > > bgeot_geometric_trans.cc, line 381 const base_matrix& 
> > > bgeot::geotrans_interpolation_context::B() const:
> > > Non invertible matrix
> > >
> > >
> > > Please let me know if you have any idea. Thank you.
> > >
> > > Best regards,
> > >
> > > Phuoc

--

  Yves Renard (address@hidden)       tel : (33) 04.72.43.87.08
  Pole de Mathematiques, INSA-Lyon             fax : (33) 04.72.43.85.29
  20, rue Albert Einstein
  69621 Villeurbanne Cedex, FRANCE
  http://math.univ-lyon1.fr/~renard

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