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<p class="MsoNormal"><span style="font-size:11.0pt">Hi all,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">The following codes are how I used to setup PC mat ordering:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:8.0pt;font-family:Monaco"> // Setup KSP/PC (at this moment, user-input options and commandline options are available)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:8.0pt;font-family:Monaco"> SNESGetKSP(snes, &ksp);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:8.0pt;font-family:Monaco"> KSPSetFromOptions(ksp);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:8.0pt;font-family:Monaco"> PC pc;<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:8.0pt;font-family:Monaco"> KSPGetPC(ksp, &pc);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:8.0pt;font-family:Monaco"> <span style="background:yellow;mso-highlight:yellow">
PCFactorSetMatOrderingType(pc, MATORDERINGRCM);</span><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:8.0pt;font-family:Monaco"> // PCFactorSetLevels(pc, 5);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:8.0pt;font-family:Monaco"> SNESSetFromOptions(snes);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">After switching to PETSc 3.21, this no longer works, and can be confirmed from ‘-snes_view’ output:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:8.0pt;font-family:Monaco"> PC Object: 1 MPI process<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:8.0pt;font-family:Monaco"> type: ilu<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:8.0pt;font-family:Monaco"> out-of-place factorization<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:8.0pt;font-family:Monaco"> 0 levels of fill<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:8.0pt;font-family:Monaco"> tolerance for zero pivot 2.22045e-14<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:8.0pt;font-family:Monaco"> using diagonal shift to prevent zero pivot [NONZERO]<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:8.0pt;font-family:Monaco"> <span style="background:yellow;mso-highlight:yellow">
matrix ordering: natural</span><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">The command line option still works, i.e., ‘-pc_factor_mat_ordering_type rcm’ gives me the correct behavior.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Questions:<o:p></o:p></span></p>
<ul style="margin-top:0in" type="disc">
<li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo1"><span style="font-size:11.0pt">Is this a bug introduced in the new version, or<o:p></o:p></span></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo1"><span style="font-size:11.0pt">With the new version, I should call this function at a different time?<o:p></o:p></span></li></ul>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Best,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">-Ling<o:p></o:p></span></p>
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