<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<style type="text/css" style="display:none;"><!-- P {margin-top:0;margin-bottom:0;} --></style>
</head>
<body dir="ltr">
<div id="divtagdefaultwrapper" style="font-size:12pt;color:#000000;font-family:'Times New Roman',Times,serif;" dir="ltr">
<p>Dear all,</p>
<p><br>
</p>
<p>I want to add more dofs to the coordinate DM to represent a curved mesh.</p>
<p>I first create a simple box mesh with one cell:</p>
<p><br>
</p>
<p></p>
<div> PetscCall(DMCreate(comm, &dm));</div>
<div> PetscCall(DMSetType(dm, DMPLEX));</div>
<div> dim = 2;</div>
<div> PetscInt n_faces[2] = {1, 1};</div>
<div> DMBoundaryType periodicity[2] = {DM_BOUNDARY_GHOSTED, DM_BOUNDARY_GHOSTED};</div>
<div> DMPlexCreateBoxMesh(comm, dim, PETSC_FALSE, n_faces, NULL, NULL, periodicity, PETSC_TRUE, &dm);</div>
<div><br>
</div>
<div>Then I add more dofs to cdm using section:</div>
<div><br>
</div>
<div>
<div> PetscCall(DMGetCoordinateDM(dm, &cdm));</div>
<div> PetscCall(DMGetLocalSection(cdm, &cs));</div>
<div> PetscCall(DMPlexGetChart(dm, &pStart, &pEnd));</div>
<div> PetscCall(PetscSectionSetChart(cs, pStart, pEnd));</div>
<div> degree = 3;</div>
<div> for(depth = 0; depth <= dim; ++ depth) {</div>
<div> PetscCall(DMPlexGetDepthStratum(cdm, depth, &pStart, &pEnd));</div>
<div> for(p = pStart; p < pEnd; ++p) {</div>
<div> <b>PetscCall(PetscSectionSetDof(cs, p, dim*PetscPowInt(degree-1, depth)));</b></div>
<div><b> PetscCall(PetscSectionSetFieldDof(cs, p, 0, dim*PetscPowInt(degree-1, depth)));</b></div>
<div> }</div>
<div> }</div>
<div> PetscCall(PetscSectionSetUp(cs));</div>
<div> PetscCall(DMSetUp(cdm));</div>
<div><br>
</div>
<div>Finally, I wish to get the vec to set the coordinates:</div>
<div><br>
</div>
<div>
<div> PetscCall(DMCreateLocalVector(cdm, &coordinates));</div>
<div> PetscScalar *pCoords = NULL;</div>
<div> PetscCall(DMPlexVecGetClosure(cdm, NULL, coordinates, 0, &pSize, &pCoords));</div>
<div> printf("pSize: %d\n", pSize);</div>
<div><br>
</div>
</div>
However, if I only use <b style="font-family: "Times New Roman", Times, serif, Times, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 16px;">PetscSectionSetDof</b>, the code reports
"<span>Section size 32 does not match Vec closure size 0</span>".</div>
<div>Instead, if I only use <b style="font-family: "Times New Roman", Times, serif, Times, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 16px;">
PetscSectionSetFieldDof</b>, the code crashes with "<span>Checking the memory for corruption."</span></div>
<div><span>It runs without error when I use both <b style="font-family: "Times New Roman", Times, serif, Times, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 16px;">
PetscSectionSetDof </b>and <b style="font-family: "Times New Roman", Times, serif, Times, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 16px;">
PetscSectionSetFieldDof</b>.</span></div>
<div><span><span style="font-family: "Times New Roman", Times, serif, Times, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 16px;"><br>
</span></span></div>
<div><span><span style="font-family: "Times New Roman", Times, serif, Times, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 16px;">Maybe I have missed something, but c</span></span>ould
you help to explain why I should both functions <b>PetscSectionSetDof</b> and <b>
PetscSectionSetFieldDof?</b></div>
<div><span><span style="font-family: "Times New Roman", Times, serif, Times, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 16px;"><span style="font-family: "Times New Roman", Times, serif, Times, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 16px;"><span style="font-family: "Times New Roman", Times, serif, Times, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 16px;">It
is not straightforward that I should again set the dofs of the section after each field of the section has been set.</span></span></span></span></div>
<div><span><span style="font-family: "Times New Roman", Times, serif, Times, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 16px;"><b style="font-family: "Times New Roman", Times, serif, Times, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 16px;"><span style="font-family: "Times New Roman", Times, serif, Times, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 16px;"><br>
</span></b></span></span></div>
<div>I can also see that <b style="font-family: "Times New Roman", Times, serif, Times, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 16px;">PetscSectionSetFieldDof </b>call
<span style="font-family: "Times New Roman", Times, serif, Times, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 16px;">
<b>PetscSectionSetDof </b>on the specific field of the section,</span></div>
<div><span>and cs->field[0] doesn't share the same address as cs itself.</span></div>
<div><span><br>
</span></div>
<div><span>Thanks in advance!</span></div>
<div>Junming</div>
<div><span><br>
</span></div>
<br>
<p></p>
<div id="Signature">
<div id="divtagdefaultwrapper" dir="ltr" style="font-size: 12pt; color: rgb(0, 0, 0); font-family: Calibri, Helvetica, sans-serif, Times, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols;">
<p style="font-family:Calibri,Helvetica,sans-serif; font-size:16px"><span style="font-family:"Times New Roman",Times,serif; font-size:12pt"></span></p>
</div>
</div>
</div>
</body>
</html>