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<p>Thanks for your suggestions!</p>
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<p>Since the code is already using tets for finite element discretization, I don't want to change it, but want a classical DMDA type partition.</p>
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<p>Bests,</p>
<p>Li</p>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Matthew Knepley <knepley@gmail.com><br>
<b>Sent:</b> Tuesday, 23 December, 2025 00:21:22<br>
<b>To:</b> liluo<br>
<b>Cc:</b> petsc-users@mcs.anl.gov; Zhang Pai<br>
<b>Subject:</b> Re: [petsc-users] A partition of DMPlex mesh similar to what DMDA provides?</font>
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On Mon, Dec 22, 2025 at 5: 46 AM liluo <liluo@ um. edu. mo> wrote: Dear PETSc developers, I’m using DMPlex to manage an unstructured mesh. However, in my case, the input mesh is actually a structured tetrahedral mesh, and its geometric domain</div>
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<div dir="ltr">On Mon, Dec 22, 2025 at 5:46 AM liluo <<a href="mailto:liluo@um.edu.mo">liluo@um.edu.mo</a>> wrote:</div>
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<p>Dear PETSc developers,</p>
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<p>I’m using <code>DMPlex</code> to manage an unstructured mesh. However, in my case, the input mesh is actually a structured tetrahedral mesh, and its geometric domain is just a simple box.</p>
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<p>Is there any PETSc functionality or recommended approach to obtain a partition similar to what
<code>DMDA</code> provides—i.e., a simple Cartesian block partition—when working with such a mesh in
<code>DMPlex</code>?</p>
<p>Any guidance or best practices would be greatly appreciated.</p>
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<div>This is trivial in 2D because triangles nicely tile the box, but in 3D tetrahedra are harder to handle.I can see three avenues:</div>
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<div>1) Manually</div>
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<div>You can use PlexPartitioner type user, which allows you to explicitly indicate the cell numbers that go to each process. This is probably more work than you want.</div>
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<div>2) Mesh Partitioner + Refinement</div>
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<div>You can run a partitioner on a small mesh, for which they are pretty good, and then refine that. This is mostly what I do.</div>
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<div>3) New algorithm</div>
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<div>Amal Timalsina published a nice algorithm for converting hexes to tets, so you could create a hex mesh that is partitioned exactly as you want, and then convert it to tets, but this would mean writing new code.</div>
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<div>Why are you using tets instead of hexes for this problem?</div>
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<div> Thanks,</div>
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<div> Matt</div>
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<p>Thank you!</p>
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<p>Bests,</p>
<p>Li Luo</p>
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