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<p class="p1"><span class="s1"><span style="font-size:10.0pt">Hello,</span></span><span class="s1"><o:p></o:p></span></p>
<p class="p1"><span class="s1"><span style="font-size:10.0pt"><o:p> </o:p></span></span></p>
<p class="p1"><span class="s1"><span style="font-size:10.0pt">I have system matrix which is symmetric and thought I could make use of
</span></span><span style="font-size:9.0pt;color:#6C36A9">MatCreateSBAIJ. </span>
<span class="s1"><span style="font-size:10.0pt">I don’t understand how to set the blocksize bs. I believe it has taken into account, when having multiple components/dofs per node.<o:p></o:p></span></span></p>
<p class="p1"><span class="s1"><o:p> </o:p></span></p>
<p class="p1" style="margin-left:72.0pt;text-indent:-54.0pt;mso-list:l0 level1 lfo2">
<![if !supportLists]><span class="s1"><span style="font-size:10.0pt"><span style="mso-list:Ignore">(i)<span style="font:7.0pt "Times New Roman"">
</span></span></span></span><![endif]><span class="s1"><span style="font-size:10.0pt">Currently, I have only one scalar field to solve so I set bs = 1 as below. Is it correct?<o:p></o:p></span></span></p>
<p class="p1"><span class="s1"><o:p> </o:p></span></p>
<p class="MsoNormal" style="background:white"><span style="font-size:9.0pt;font-family:Menlo;color:black;mso-fareast-language:EN-GB"> ierr =
</span><span style="font-size:9.0pt;font-family:Menlo;color:#6C36A9;mso-fareast-language:EN-GB">MatCreateSBAIJ</span><span style="font-size:9.0pt;font-family:Menlo;color:black;mso-fareast-language:EN-GB">(</span><span style="font-size:9.0pt;font-family:Menlo;color:#6C36A9;mso-fareast-language:EN-GB">PETSC_COMM_WORLD</span><span style="font-size:9.0pt;font-family:Menlo;color:black;mso-fareast-language:EN-GB">,
</span><span style="font-size:9.0pt;font-family:Menlo;color:#1C00CF;mso-fareast-language:EN-GB">1</span><span style="font-size:9.0pt;font-family:Menlo;color:black;mso-fareast-language:EN-GB">,
</span><span style="font-size:9.0pt;font-family:Menlo;color:#643820;mso-fareast-language:EN-GB">PETSC_DECIDE</span><span style="font-size:9.0pt;font-family:Menlo;color:black;mso-fareast-language:EN-GB">,
</span><span style="font-size:9.0pt;font-family:Menlo;color:#643820;mso-fareast-language:EN-GB">PETSC_DECIDE</span><span style="font-size:9.0pt;font-family:Menlo;color:black;mso-fareast-language:EN-GB">, N, N, d_nz,
</span><span style="font-size:9.0pt;font-family:Menlo;color:#643820;mso-fareast-language:EN-GB">PETSC_NULL</span><span style="font-size:9.0pt;font-family:Menlo;color:black;mso-fareast-language:EN-GB">, o_nz,
</span><span style="font-size:9.0pt;font-family:Menlo;color:#643820;mso-fareast-language:EN-GB">PETSC_NULL</span><span style="font-size:9.0pt;font-family:Menlo;color:black;mso-fareast-language:EN-GB">, &</span><span style="font-size:9.0pt;font-family:Menlo;color:#326D74;mso-fareast-language:EN-GB">A</span><span style="font-size:9.0pt;font-family:Menlo;color:black;mso-fareast-language:EN-GB">);
</span><span style="font-size:9.0pt;font-family:Menlo;color:#643820;mso-fareast-language:EN-GB">CHKERRQ</span><span style="font-size:9.0pt;font-family:Menlo;color:black;mso-fareast-language:EN-GB">(ierr);<o:p></o:p></span></p>
<p class="MsoNormal" style="background:white"><span style="font-size:9.0pt;font-family:Menlo;color:black;mso-fareast-language:EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal" style="background:white"><span style="font-size:9.0pt;font-family:Menlo;color:black;mso-fareast-language:EN-GB"> ierr =
</span><span style="font-size:9.0pt;font-family:Menlo;color:#6C36A9;mso-fareast-language:EN-GB">MatCreateVecs</span><span style="font-size:9.0pt;font-family:Menlo;color:black;mso-fareast-language:EN-GB">(</span><span style="font-size:9.0pt;font-family:Menlo;color:#326D74;mso-fareast-language:EN-GB">A</span><span style="font-size:9.0pt;font-family:Menlo;color:black;mso-fareast-language:EN-GB">,
&</span><span style="font-size:9.0pt;font-family:Menlo;color:#326D74;mso-fareast-language:EN-GB">right</span><span style="font-size:9.0pt;font-family:Menlo;color:black;mso-fareast-language:EN-GB">, &</span><span style="font-size:9.0pt;font-family:Menlo;color:#326D74;mso-fareast-language:EN-GB">left</span><span style="font-size:9.0pt;font-family:Menlo;color:black;mso-fareast-language:EN-GB">);</span><span style="font-size:9.0pt;font-family:Menlo;color:#643820;mso-fareast-language:EN-GB">CHKERRQ</span><span style="font-size:9.0pt;font-family:Menlo;color:black;mso-fareast-language:EN-GB">(ierr);<o:p></o:p></span></p>
<p class="MsoNormal" style="background:white"><span style="font-size:9.0pt;font-family:Menlo;color:black;mso-fareast-language:EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal" style="background:white"><span style="font-size:9.0pt;font-family:Menlo;color:black;mso-fareast-language:EN-GB"><o:p> </o:p></span></p>
<p class="MsoListParagraph" style="margin-left:72.0pt;text-indent:-54.0pt;mso-list:l0 level1 lfo2;background:white">
<![if !supportLists]><span style="font-size:9.0pt;font-family:Menlo;color:black;mso-fareast-language:EN-GB"><span style="mso-list:Ignore">(ii)<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:9.0pt;font-family:Menlo;color:black;mso-fareast-language:EN-GB">If you multiple components/dofs per node, say 2, is the then block size = 2?<o:p></o:p></span></p>
<p class="MsoListParagraph" style="margin-left:72.0pt;background:white"><span style="font-size:9.0pt;font-family:Menlo;color:black;mso-fareast-language:EN-GB"><o:p> </o:p></span></p>
<p class="MsoListParagraph" style="margin-left:72.0pt;text-indent:-54.0pt;mso-list:l0 level1 lfo2;background:white">
<![if !supportLists]><span style="font-size:9.0pt;font-family:Menlo;color:black;mso-fareast-language:EN-GB"><span style="mso-list:Ignore">(iii)<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:9.0pt;font-family:Menlo;color:black;mso-fareast-language:EN-GB">To apply homogenous Dirichlet boundary condition, I make use of MatZeroRowsColumns. It works in serial but while applying in parallel the following
error is thrown, <o:p></o:p></span></p>
<p class="p1"><span class="s1"><o:p> </o:p></span></p>
<p class="p1" style="text-indent:36.0pt"><span class="s1"><span style="font-size:10.0pt">[0]PETSC ERROR: No method zerorowscolumns for Mat of type mpisbaij<o:p></o:p></span></span></p>
<p class="p1" style="text-indent:36.0pt"><span class="s1"><span style="font-size:10.0pt"><o:p> </o:p></span></span></p>
<p class="p1" style="text-indent:36.0pt"><span class="s1"><span style="font-size:10.0pt"> How do I fix it?<o:p></o:p></span></span></p>
<p class="p1"><span class="s1"><span style="font-size:10.0pt"><o:p> </o:p></span></span></p>
<p class="MsoListParagraph" style="margin-left:72.0pt;text-indent:-54.0pt;mso-list:l0 level1 lfo2">
<![if !supportLists]><span style="mso-list:Ignore">(iv)<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]><span style="font-size:9.0pt;font-family:Menlo;color:black;mso-fareast-language:EN-GB">Is there performance again, when using
</span><span style="font-size:9.0pt;color:#6C36A9">MatCreateSBAIJ </span><span style="font-size:9.0pt;font-family:Menlo;color:black;mso-fareast-language:EN-GB">for large symmetric system matrix? I read there is more communication involved.</span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Best,</p>
<p class="MsoNormal">Karthik.</p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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