<div dir="ltr"><div dir="ltr">On Mon, Feb 28, 2022 at 2:15 PM Ferrand, Jesus A. <<a href="mailto:FERRANJ2@my.erau.edu">FERRANJ2@my.erau.edu</a>> wrote:<br></div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div dir="ltr">
<div style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(0,0,0);background-color:rgb(255,255,255)">
Dear PETSc team:<br>
</div>
<div style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(0,0,0);background-color:rgb(255,255,255)">
<br>
</div>
<div style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(0,0,0);background-color:rgb(255,255,255)">
I am working on an FEA code that solves the elasticity equation using P1 elements. I want to write Vecs to ParaView in .vtk format. I can output the displacements by defining a PetscSection that assigned dof over the vertices of my mesh. I can export this Vec
using PetscViewerVTKAddField() and DMPlexVTKWriteAll(). Now I want to export strains and stresses using the same VTK functions, but these Vecs need a different PetscSection (one that assigns dof over the cells). My concern is that to output displacements I
attached the PetscSection to the DMPlex using DMSetLocalSection(). I'm not sure if I can define another local section for my cell-based strains and stresses and set it as a local section . </div></div></blockquote><div><br></div><div>1. I think this is possible, and will try to lay it out below. However, VTK is not a great format, so I will offer another, more flexible solution, afterwards.</div><div><br></div><div> The way to do this is to call DMClone(dm, &sdm) to get another DM with the same topology. Then set the Section to be your cellwise section</div><div> for strains. Then you just output that vector into the same VTK file. Since the topology is the same, this will work.</div><div><br></div><div>2. We have converted from VTK to HDF5 for Paraview. It is _much_ more flexible.</div><div><br></div><div> You have the same two DMs, and you output one of them to the HDF5 file suing DMView(), and all the fields using VecView(). I usually use</div><div> DMViewFromOptions() and VecViewFromOptions() and then something like </div><div><br></div><div> -dm_view hdf5:sol.h5 -disp_vec_view hdf5:sol.h5::append -strain_vec_view hdf5:sol.h5::append</div><div><br></div><div> and then process that file to make an XDMF file sol.xmf</div><div><br></div><div> $PETSC_DIR/lib/petc/bin/petsc_gen_xdmf.py sol.h5</div><div><br></div><div> All the fields will show up in Paraview when you load sol.xmf. This approach handles multiple timesteps, multiple meshes, mesh change, and many other things.</div><div><br></div><div> THanks,</div><div><br></div><div> Matt</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">
<div style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(0,0,0);background-color:rgb(255,255,255)">
My questions are:</div>
<div style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(0,0,0);background-color:rgb(255,255,255)">
<ul>
<li>Could I perhaps do this with DMSetGlobalSection()?<br>
<span></span></li><li><span>Can a DM hold multiple PetscSections (say multiple local sections and multiple global sections)?</span></li><ul>
<li><span>If so, how can select individual ones to properly output Vecs with DMPlexVTKWriteAll()?<br>
</span></li></ul>
<li><span>Does the local PetscSection depend on the Global one or vice versa? </span></li><li><span>Can I avoid having to define a PetscSection altogether for my cell-based Vecs if I use DMCreateGlobalVector()?</span></li><ul>
<li><span>I got this idea from the source code of DMPlexCreateRankField(), which I successfully use to visualize my mesh partition.<br>
</span></li></ul>
</ul>
</div>
<div style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(0,0,0);background-color:rgb(255,255,255)">
Sorry for the mouthful. <br>
</div>
<div>
<div style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(0,0,0)">
<br>
</div>
<div id="gmail-m_5748242978993678407Signature">
<div>
<div style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(0,0,0)">
</div>
<div></div>
<div></div>
<div id="gmail-m_5748242978993678407divtagdefaultwrapper" dir="ltr" style="font-size:12pt;color:rgb(0,0,0);font-family:Calibri,Helvetica,sans-serif">
<p style="margin-top:0px;margin-bottom:0px"></p>
<div>
<p style="margin:0px 0px 10.66px"></p>
<div>
<p style="background:none 0% 0% repeat scroll white;margin:0px 0px 11px;line-height:normal">
<span style="margin:0px;color:black;font-family:"Times New Roman",Times,serif;font-size:12pt">Sincerely:</span></p>
<p style="background:none 0% 0% repeat scroll white;margin:0px;line-height:normal">
<span style="margin:0px;color:red;font-family:"Courier New",monospace;font-size:14pt"><b><span style="font-family:"Courier New",monospace">J.A. Ferrand</span></b></span><u><span style="margin:0px;color:red;font-family:"Swis721 BlkCn BT",sans-serif;font-size:12pt"></span></u></p>
<p style="background:none 0% 0% repeat scroll white;margin:0px;line-height:normal">
<span style="margin:0px;color:black;font-family:Courant;font-size:12pt">Embry-Riddle Aeronautical University - Daytona Beach FL</span></p>
<p style="background:none 0% 0% repeat scroll white;margin:0px;line-height:normal">
<span style="margin:0px;color:black;font-family:Courant;font-size:12pt">M.Sc. Aerospace Engineering | May 2022</span></p>
<p style="background:none 0% 0% repeat scroll white;margin:0px;line-height:normal">
<span style="margin:0px;color:black;font-family:Courant;font-size:12pt">B.Sc. Aerospace Engineering</span></p>
<p style="background:none 0% 0% repeat scroll white;margin:0px;line-height:normal">
<span style="margin:0px;color:black;font-family:Courant;font-size:12pt">B.Sc. Computational Mathematics</span></p>
<p style="background:none 0% 0% repeat scroll white;margin:0px;line-height:normal">
<span style="margin:0px;color:rgb(0,0,0);font-family:Courant;font-size:12pt"> </span></p>
<p style="background:none 0% 0% repeat scroll white;margin:0px;line-height:normal">
<span style="margin:0px;color:black;font-family:Courant;font-size:12pt"><span style="color:rgb(0,0,0);font-family:Courant;font-size:12pt;background-color:rgb(255,255,255);display:inline">Sigma Gamma Tau</span><span style="color:rgb(0,0,0);font-family:Courant;font-size:12pt;background-color:rgb(255,255,255);display:inline"> </span><br>
</span></p>
<p style="background:none 0% 0% repeat scroll white;margin:0px;line-height:normal">
<span style="margin:0px;color:rgb(0,0,0);font-family:Courant;font-size:12pt">Tau Beta Pi</span></p>
<p style="background:none 0% 0% repeat scroll white;margin:0px;line-height:normal">
<span style="margin:0px;color:black;font-family:Courant;font-size:12pt"><span style="margin:0px;color:rgb(0,0,0);font-family:Courant;font-size:12pt">Honors Program</span></span></p>
<p style="background:none 0% 0% repeat scroll white;margin:0px;line-height:normal">
<span style="margin:0px;color:black;font-family:Courant;font-size:12pt"> </span></p>
<p style="background:none 0% 0% repeat scroll white;margin:0px;line-height:normal">
<u><span style="margin:0px;color:black;font-family:Courant;font-size:12pt">Phone:</span></u><span style="margin:0px;color:black;font-family:Courant;font-size:12pt"> (386)-843-1829</span></p>
<p style="background:none 0% 0% repeat scroll white;margin:0px;line-height:normal">
<u><span style="margin:0px;color:black;font-family:Courant;font-size:12pt">Email(s):</span></u><span style="margin:0px;color:black;font-family:Courant;font-size:12pt"> <a href="mailto:ferranj2@my.erau.edu" target="_blank">ferranj2@my.erau.edu</a></span></p>
<p style="background:none 0% 0% repeat scroll white;margin:0px;line-height:normal;text-indent:0.5in">
<span style="margin:0px;color:black;font-family:Courant;font-size:12pt"><span style="margin:0px">
</span><a href="mailto:jesus.ferrand@gmail.com" target="_blank">jesus.ferrand@gmail.com</a></span></p>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</blockquote></div><br clear="all"><div><br></div>-- <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="http://www.cse.buffalo.edu/~knepley/" target="_blank">https://www.cse.buffalo.edu/~knepley/</a><br></div></div></div></div></div></div></div></div>