[petsc-users] Gmsh 8-noded quadrilateral

[Susanne Claus]

Dear Matthew,

Thank you so much.
I have a attached a small 8-noded quadrilateral mesh file (Version 4 
ASCII) generated with gmsh 4.8.4.

Best wishes,
Susanne

On 10.02.2022 16:23, Matthew Knepley wrote:

> On Thu, Feb 10, 2022 at 10:12 AM Susanne Claus <susanne.claus at onera.fr> 
> wrote:
> 
>> Hello,
>> 
>> I am using DMPlex for the mesh structure of a solid mechanics finite 
>> element code. I mainly use gmsh as input file format. When I try to 
>> read in 8-noded Quadrilaterals (Element type 16 in gmsh) DMPlex tells 
>> me that this element type is unknown. However a 9-noded Quadrilateral 
>> can be read without problem. On inspecting the plexgmsh.c source code 
>> I can see that 8-noded quadrilaterals are deactivated:
>> 
>> #if 0
>> 146:   {20, GMSH_TRI, 2, 3, 3,  9, NULL},
>> 147:   {16, GMSH_QUA, 2, 2, 4,  8, NULL},
>> 
>> For our application these 8-noded quadrilateral are very important.
>> 
>> Is there any reason why they have not been implemented/deactivated in 
>> the dmplex gmsh reader?
> 
> No, we can handle them in the same way I think. Let me look at it. 
> Hopefully it is easy.
> 
> Thanks,
> 
> Matt
> 
>> Thank you for all the great work you are doing. PETSc is amazing.
>> 
>> Best wishes,
>> Susanne Claus
> 
> --
> 
> 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
> 
> https://www.cse.buffalo.edu/~knepley/ [1]

-- 

Susanne Claus
Ingénieur Chercheur
Applied Mathematics and Scientific Computing Group
DTIS

ONERA - The French Aerospace Lab
6 Chemin de la Vauve aux Granges, 91120 Palaiseau

Links:
------
[1] http://www.cse.buffalo.edu/~knepley/
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