[petsc-dev] Inquiry about contributing to MMG interface

[neil liu]

It seems the figures were  broken. Please see the following attached.

On Wed, Feb 5, 2025 at 10:36 AM neil liu <liufield at gmail.com> wrote:

> Hi, Mark,
>
> For example, in the left figure, the yellow rectangular face needs to be
> preserved during mesh refinement. However, without specifying its four
> corner points, the rectangle cannot be maintained, as shown in the right
> figure. Additionally, the four edges of this face must be recorded and
> retrieved for post-processing.
>
> This yellow face is an *open boundary*, meaning it is not an interface
> between different materials. To ensure its preservation during mesh
> refinement, MMG must be run in *opnbdy* (open boundary) mode.
>
> Thanks a lot,
>
> Xiaodong
> [image: image.png] [image: image.png]
>
>
> On Wed, Feb 5, 2025 at 10:05 AM Matthew Knepley <knepley at gmail.com> wrote:
>
>> On Wed, Feb 5, 2025 at 9:52 AM neil liu <liufield at gmail.com> wrote:
>>
>>> Dear developers,
>>>
>>> I am currently working with MMG in the context of PETSc and have
>>> identified a need to modify the existing MMG interface,
>>> DMAdaptMetric_Mmg_Plex(), for our use case. Given these requirements, I
>>> would like to explore the feasibility of contributing to PETSc to enhance
>>> this interface, which has been verified and validated in our research code.
>>> *Proposed Modifications:*
>>>
>>>    1.
>>>
>>>    *Additional Labels for Physical Entities:*
>>>    - In addition to the existing bdLabel and rgLabel, our case requires
>>>       two additional labels to represent physical vertices and edges within the
>>>       computational domain (3D).
>>>
>>> I am open to this. Can you be more specific about what it means?
>>
>>>
>>>    1.
>>>       - One approach is to introduce two new parameters in the
>>>       subroutine’s input list. However, this may require modifications across
>>>       related components, such as Pragmatic.
>>>
>>> This is not a problem. I can modify those.
>>
>>>
>>>    1.
>>>
>>>    *Support for Open Boundaries:*
>>>    - The current interface does not support open boundaries, a feature
>>>       available in MMG.
>>>       - As a result, several MMG benchmark cases involving open
>>>       boundary remeshing cannot be executed within PETSc.
>>>
>>> Can you explain what this means? What is an open boundary exactly?
>>
>>
>>> Would this be a viable contribution to PETSc? If so, I would appreciate
>>> any guidance on the best approach to implementing these changes while
>>> maintaining compatibility with existing features.
>>>
>> Yes. Please make a fork of the petsc repo, make a branch with the
>> proposed changes, make an MR for that branch, and add me to your fork (I am
>> knepley on GitLab). I can help you get it going.
>>
>>   Thanks,
>>
>>     Matt
>>
>>
>>> Looking forward to your thoughts.
>>>
>>> Best regards,
>>>
>>> Thanks,
>>> Xiaodong
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>
>> --
>> 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
>>
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>>
>
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