<div dir="ltr"><div dir="ltr">On Sun, Feb 2, 2025 at 3:59 PM Aldo Bonfiglioli <<a href="mailto:aldo.bonfiglioli@unibas.it">aldo.bonfiglioli@unibas.it</a>> wrote:</div><div class="gmail_quote gmail_quote_container"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><u></u>
<div>
<p>Dear all,</p>
<p>it is unclear to me what is being flagged with the "marker" flag
when a mesh is created using DMPlexCreate.</p>
<p>The 2D triangular mesh pictured in the enclosed pdf has the
following features:</p>
<p>
</p><blockquote type="cite"><span style="font-family:monospace"><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">DM Object:
2D plex 1 MPI process</span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">
</span><br>
<span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">type:
plex</span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">
</span><br>
<span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">2D plex
in 2 dimensions:</span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">
</span><br>
<span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">Number
of 0-cells per rank: 12</span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">
</span><br>
<span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">Number
of 1-cells per rank: 23</span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">
</span><br>
<span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">Number
of 2-cells per rank: 12</span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">
</span><br>
<span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">Labels:</span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">
</span><br>
<span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">celltype:
3 strata with value/size (0 (12), 1 (23), 3 (12))</span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">
</span><br>
<span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">depth:
3 strata with value/size (0 (12), 1 (23), 2 (12))</span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">
</span><br>
<span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">marker:
1 strata with value/size (1 (20))</span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">
</span><br>
<span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">Face
Sets: 4 strata with value/size (1 (3), 2 (2), 3 (3), 4 (2))</span><br>
<span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">
</span><br>
</span></blockquote>
i.e 12 gridpoints, 23 edges and 12 triangular cells.<p></p>
<p>When I call DMGetStratumSize at stratum 0 to 2, this is what I
get.<br>
</p>
<p>
</p><blockquote type="cite"><span style="font-family:monospace"><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)"> </span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">CreateSectionAlternate
DMGetStratumSize found</span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)"> </span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">0 'marker'
points @ depth</span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)"> </span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">0 on PE#</span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)"> </span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">0</span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">
</span><br>
<span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">CreateSectionAlternate
DMGetStratumSize found</span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)"> </span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">20 'marker'
points @ depth</span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)"> </span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">1 on PE#</span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)"> </span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">0</span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">
</span><br>
<span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">CreateSectionAlternate
DMGetStratumSize found</span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)"> </span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">0 'marker'
points @ depth</span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)"> </span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">2 on PE#</span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)"> </span><span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">0</span><br>
<span style="color:rgb(0,0,0);background-color:rgb(255,255,255)">
</span><br>
</span></blockquote>
Is the marker flagging boundary edges or boundary vertices (nodes)
? In any case, why are there 20, instead of 10?</div></blockquote><div><br></div><div>By default the "marker" label marks all k-cells on the boundary. In this case it means</div><div><br></div><div> 10 vertices + 10 edges = 20 points</div><div><br></div><div>You can see what is in the label using</div><div><br></div><div> -dm_view -dm_plex_view_labels marker</div><div><br></div><div>with</div><div><br></div><div> DMViewFromOptions(dm, NULL, "-dm_view")</div><div><br></div><div>in your code.</div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div><p></p>
<p>Finally: I believe face sets refers to boundary faces, where each
side of the square domain has been given a different flag.</p>
<p></p></div></blockquote><div>Yes. </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div><p>How do I access the face sets information ?</p></div></blockquote><div>DMLabel label;</div><div><br></div><div>PetscCall(DMGetLabel(dm, "Face Sets", &label));</div><div><br></div><div> Thanks,</div><div><br></div><div> Matt</div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div>
<p>Thanks,</p>
<p>Aldo <br>
</p>
<p><br>
</p>
<pre cols="72">--
Dr. Aldo Bonfiglioli
Associate professor of Fluid Machines
Scuola di Ingegneria
Universita' della Basilicata
V.le dell'Ateneo lucano, 10 85100 Potenza ITALY
tel:+39.0971.205203 fax:+39.0971.205215
web: <a href="https://urldefense.us/v3/__http://docenti.unibas.it/site/home/docente.html?m=002423__;!!G_uCfscf7eWS!c6_YYKL6k6FdMvXiZuhIJ2t5rbgB45aqicDR0WpLsZSgrs7NO0SMggi_L8KB2ZKd-w8JlcGQJTFm-uotq1RhZRDxD575sfToW2A$" target="_blank">http://docenti.unibas.it/site/home/docente.html?m=002423</a></pre>
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</blockquote></div><div><br clear="all"></div><div><br></div><span class="gmail_signature_prefix">-- </span><br><div dir="ltr" class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div>What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.<br>-- Norbert Wiener</div><div><br></div><div><a href="https://urldefense.us/v3/__http://www.cse.buffalo.edu/*knepley/__;fg!!G_uCfscf7eWS!Zs0PBHmkwRS6C-HyPNWsfCXfxTmHZ51FTqXs6A-ujrSlUUYpguXpO2Cg1tShryNL4k0RYpZVhUjgM5Vlw3jP$" target="_blank">https://www.cse.buffalo.edu/~knepley/</a><br></div></div></div></div></div></div></div></div>