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<p class="MsoNormal">Dear PETSc folks,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I have an emerging need to resolve the performance issue in building sparse matrix in PETSc.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I am are currently having some performance issues in building the sparse matrix in PETSc.  I am trying to input the inverted matrix from ScaLAPACK into PETSc.  This matrix is partitioned into series of submatrices with indices identified
 as block-cyclically distributed pattern.  <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Here are the options I have tested in PETSc to build them into PETSc and their limitations:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="mso-list:Ignore">1.<span style="font:7.0pt "Times New Roman"">      
</span></span><![endif]>MatSetValue(s)(…) is very easy to use.  However, the assembling process is extremely slow and expensive;<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="mso-list:Ignore">2.<span style="font:7.0pt "Times New Roman"">      
</span></span><![endif]>MatSetValuesBlocked(..) can speed up the assembly.  However, it is not well-fit for block-cyclically distributed matrices; and<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="mso-list:Ignore">3.<span style="font:7.0pt "Times New Roman"">      
</span></span><![endif]>MatCreateMPIAIJwithArrays(…) seems to be promising.  However, it is not straightforward to use for block-cyclically distributed matrices.<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="mso-list:Ignore">4.<span style="font:7.0pt "Times New Roman"">      
</span></span><![endif]>Customizeing MatSetValuesBlocked(…) such that we can specify the indices for (*mat->ops->setvaluesblocked)(…).  However, I have trouble to locate proper line for<o:p></o:p></p>
<p class="MsoListParagraph" style="margin-left:1.0in;text-indent:.5in">mat->ops->setvaluesblocked=&unknownFunctionName<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The question is what other options you have to resolve this performance issue? From your experience, do you guys have a worked example to build PETSc sparse matrix from block-cyclically distributed matrices obtained from ScaLAPACK with
 good performance?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I appreciate your inputs on this issue.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Jinquan<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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