On Friday, June 20th, 2025 at 9:37 PM, Matthew Knepley
wrote:
> I do have this implemented. If you give -dm_plex_high_order_view, it will
> refine the grid and project into the linear space.
> You can see that the code is pretty simple:
Thanks ,that will be handy. Perhaps this whole idea of us
Thank you once again, the code provides exactly what needed.
An alternative for the VTK use was subdividing cells using corner nodes and
integration points, such that all cells were first order. Any "better"
alternative format/visualization software for this purpose?
Possibly the last question i
See image attached.
Connectivity of the top mesh (first order triangle), can be obtained with the
code shared before.
Connectivity of the bottom mesh (second order triangle) is what I would be
interested in obtaining.
However, given your clarification on what the Plex and the PetscSection handle
Thank you. For now, I am dealing with vertices only.
Perhaps I did not explain myself properly, or I misunderstood your response.
What I meant to say is, given an element of order higher than one, the
connectivity matrix I obtain this way only contains as many entries as the
first order element:
I might be able to answer myself.
in the $Nodes section, the mid-face nodes are included with dimension 2 a.k.a
faces; e.g. the ninth node
2 6 0 1 <-- 2 is the element dimension, 6 is the tag
9
0.5 0.5 1.0
So when creating groups for the surfaces, these nodes are also included into
their own p
Thank you for the code; it provides exactly what I was looking for.
Following up on this matter, does this method not work for higher order
elements? For example, using an 8-node quadrilateral, exporting to a
PETSC_VIEWER_HDF5_VIZ viewer provides the correct matrix of node coordinates in
geomet
Hello,
In the mesh attached, a 1x1x1 cube with 8 nodes, physical groups are defined
for the 6 bounding faces only. According to the GUI, and looking at the MSH
file in $Entities, there are no physical groups for nodes.
Using the following code:
---
#include
#include
int main(int argc, char
Hello,
Thank you the various options.
Use case here would be obtaining the exact output generated by option 1),
DMView() with PETSC_VIEWER_HDF5_VIZ; in particular, the matrix generated under
/viz/topology/cells.
> There are several ways you might do this. It helps to know what you are
> aimin
Hello,
I am trying to build the connectivity matrix for a mesh; i.e. the indices of
the nodes that compose each cell.
Example:
0---1
|.\.|
|...\...|
|.\.|
3---2
the matrix would look like [ [0, 3, 2], [2, 1, 0] ] (possibly different
ordering).
One option is using DMPlexGetTr
Hello,
I ran into a seemingly non-consistent behavior of the function
[DMPlexComputeCellGeometryFEM](https://urldefense.us/v3/__https://petsc.org/release/manualpages/DMPlex/DMPlexComputeCellGeometryFEM/__;!!G_uCfscf7eWS!YEv7_aaCdN0cxV8sUhRBIACYZGNNcwQusNjEpfVep6yOAxRYE9f8kw4XiVENrjEvQEVwiheebMTQV
work, but perhaps there is a different idea behind it.
Thanks.
Noam
On Tuesday, March 26th, 2024 at 11:17 PM, Matthew Knepley
wrote:
> On Tue, Mar 26, 2024 at 2:23 PM Noam T. via petsc-users
> wrote:
>
>> Hello, I am trying to understand the FE Tabulatio
Hello,
I am trying to understand the FE Tabulation data obtained from e.g .
PetscFEComputeTabulation. Using a 2D mesh with a single triangle, first order,
with vertices (0,0), (0,1), (1,0) (see msh file attached), and a single
quadrature point at (1/3, 1/3), one gets Nb = 6, Nc = 2, Nq = 1, and
hould be able to access those of
>>>> cell/face/vertex as well?
>>>
>>> Shoot, yes this changed after another request. Yes, we can put in a flag
>>> for that. Should not take long.
>>>
>>> Thanks,
>>>
>>> Matt
>>>
gt; PS: Using PETSc 3.20.3
>>
>> Thanks,
>> Noam
>> On Thursday, January 11th, 2024 at 5:28 PM, Matthew Knepley
>> wrote:
>>
>>> On Thu, Jan 11, 2024 at 11:18 AM Noam T. via petsc-users
>>> wrote:
>>>
>>>> Would it be feasi
access those of
cell/face/vertex as well?
PS: Using PETSc 3.20.3
Thanks,
Noam
On Thursday, January 11th, 2024 at 5:28 PM, Matthew Knepley
wrote:
> On Thu, Jan 11, 2024 at 11:18 AM Noam T. via petsc-users
> wrote:
>
>> Would it be feasible to have an option (e.g. new flag alo
Would it be feasible to have an option (e.g. new flag along the lines of
-dm_plex_gmsh_...) that allows the user to access both the default sets (Cell /
Face / Vertex) together with user-defined gorups (those under $PhysicalNames,
available when using -dm_plex_gmsh_use_regions)?
That is, with a
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