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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Dear folks,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I have a question on how to use mumps properly in PETSc.  It appears that I didn’t set up mumps right.  I followed the example in
<o:p></o:p></span></p>
<p class="MsoNormal" style="text-indent:.5in"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><a href="http://www.mcs.anl.gov/petsc/petsc-dev/src/mat/examples/tests/ex125.c.html">http://www.mcs.anl.gov/petsc/petsc-dev/src/mat/examples/tests/ex125.c.html</a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">to set up my program.  Here is my situation on using the default setting
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<pre>        <a href="http://www.mcs.anl.gov/petsc/petsc-dev/docs/manualpages/Sys/PetscInt.html#PetscInt">PetscInt</a> icntl_7 = 5;<o:p></o:p></pre>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New"">       
<a href="http://www.mcs.anl.gov/petsc/petsc-dev/docs/manualpages/Mat/MatMumpsSetIcntl.html#MatMumpsSetIcntl">
MatMumpsSetIcntl</a>(F,7,icntl_7);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">in the example ex125.c:
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><span style="mso-list:Ignore">1.<span style="font:7.0pt "Times New Roman"">      
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">The program work fine on all
<b>small</b> models (sparse matrices at  the order of m= 894, 1097, 31k with a dense matrix included in the sparse matrix). The residuals are at the magnitude of 10^-3.<o:p></o:p></span></p>
<p class="MsoListParagraph"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><span style="mso-list:Ignore">2.<span style="font:7.0pt "Times New Roman"">      
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">The program has some issues on
<b>medium</b> size problem  (m=460k with a dense matrix at the order of n=30k included in the sparse matrix).  The full sparse matrix is sized at 17GB.<o:p></o:p></span></p>
<p class="MsoListParagraph" style="margin-left:1.0in;text-indent:-.25in;mso-list:l0 level2 lfo1">
<![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><span style="mso-list:Ignore">a.<span style="font:7.0pt "Times New Roman"">      
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">We used another software to generate sparse matrix by using 144 cores: 
<o:p></o:p></span></p>
<p class="MsoListParagraph" style="margin-left:1.5in;text-indent:-1.5in;mso-text-indent-alt:-9.0pt;mso-list:l0 level3 lfo1">
<![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><span style="mso-list:Ignore"><span style="font:7.0pt "Times New Roman"">                                                              
</span>i.<span style="font:7.0pt "Times New Roman"">      </span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">When I used the resource from 144 cores (12 nodes with 48GB/node), it could not provide
 the solution.  There was a complain on the memory violation.<o:p></o:p></span></p>
<p class="MsoListParagraph" style="margin-left:1.5in;text-indent:-1.5in;mso-text-indent-alt:-9.0pt;mso-list:l0 level3 lfo1">
<![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><span style="mso-list:Ignore"><span style="font:7.0pt "Times New Roman"">                                                            
</span>ii.<span style="font:7.0pt "Times New Roman"">      </span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">When I used the resource from 432 cores (36 nodes with 48GB/node), it provided the solution. 
<o:p></o:p></span></p>
<p class="MsoListParagraph" style="margin-left:1.0in;text-indent:-.25in;mso-list:l0 level2 lfo1">
<![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><span style="mso-list:Ignore">b.<span style="font:7.0pt "Times New Roman"">     
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">We used another software to generate the same sparse matrix by using 576 cores: 
<o:p></o:p></span></p>
<p class="MsoListParagraph" style="margin-left:1.5in;text-indent:-1.5in;mso-text-indent-alt:-9.0pt;mso-list:l0 level3 lfo1">
<![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><span style="mso-list:Ignore"><span style="font:7.0pt "Times New Roman"">                                                              
</span>i.<span style="font:7.0pt "Times New Roman"">      </span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">When I used the resource from 576 cores (48 nodes with 48GB/node), it could not provide
 the solution.  There was a complain on the memory violation.<o:p></o:p></span></p>
<p class="MsoListParagraph" style="margin-left:1.5in;text-indent:-1.5in;mso-text-indent-alt:-9.0pt;mso-list:l0 level3 lfo1">
<![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><span style="mso-list:Ignore"><span style="font:7.0pt "Times New Roman"">                                                            
</span>ii.<span style="font:7.0pt "Times New Roman"">      </span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">When I used the resource from 1152 cores (96 nodes with 48GB/node), it provided the solution. 
<o:p></o:p></span></p>
<p class="MsoListParagraph" style="margin-left:1.5in"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><span style="mso-list:Ignore">3.<span style="font:7.0pt "Times New Roman"">      
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">The program could not solve the
<b>large</b> size problem (m=640k with a dense matrix at the order of n=178k included in the sparse matrix).  The full sparse matrix is sized at 511GB.<o:p></o:p></span></p>
<p class="MsoListParagraph" style="margin-left:1.0in;text-indent:-.25in;mso-list:l0 level2 lfo1">
<![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><span style="mso-list:Ignore">a.<span style="font:7.0pt "Times New Roman"">      
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">We used another software to generate sparse matrix by using 900 cores: 
<o:p></o:p></span></p>
<p class="MsoListParagraph" style="margin-left:1.5in;text-indent:-1.5in;mso-text-indent-alt:-9.0pt;mso-list:l0 level3 lfo1">
<![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><span style="mso-list:Ignore"><span style="font:7.0pt "Times New Roman"">                                                              
</span>i.<span style="font:7.0pt "Times New Roman"">      </span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">When I used the resource from 900 cores (75 nodes with 48GB/node), it could not provide
 the solution.  There was a complain on the memory violation.<o:p></o:p></span></p>
<p class="MsoListParagraph" style="margin-left:1.5in;text-indent:-1.5in;mso-text-indent-alt:-9.0pt;mso-list:l0 level3 lfo1">
<![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><span style="mso-list:Ignore"><span style="font:7.0pt "Times New Roman"">                                                            
</span>ii.<span style="font:7.0pt "Times New Roman"">      </span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">When I used the resource from 2400 cores (200 nodes with 48GB/node), it STILL COULD NOT
 provide the solution.  <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">My confusion starts from the medium size problem:<o:p></o:p></span></p>
<p class="MsoListParagraph" style="margin-left:41.45pt;text-indent:-.25in;mso-list:l1 level1 lfo2">
<![if !supportLists]><span style="font-size:11.0pt;font-family:Symbol;color:#1F497D"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">        
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">It seems something was not right in the default setting in ex125.c for these problems. 
<o:p></o:p></span></p>
<p class="MsoListParagraph" style="margin-left:41.45pt;text-indent:-.25in;mso-list:l1 level1 lfo2">
<![if !supportLists]><span style="font-size:11.0pt;font-family:Symbol;color:#1F497D"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">        
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I got the info that METIS was used instead of ParMETIS in solving these problems. 
<o:p></o:p></span></p>
<p class="MsoListParagraph" style="margin-left:41.45pt;text-indent:-.25in;mso-list:l1 level1 lfo2">
<![if !supportLists]><span style="font-size:11.0pt;font-family:Symbol;color:#1F497D"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">        
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Furthermore, it appears that there was unreasonable demand on the solver even on the medium size problem.   <o:p></o:p></span></p>
<p class="MsoListParagraph" style="margin-left:41.45pt;text-indent:-.25in;mso-list:l1 level1 lfo2">
<![if !supportLists]><span style="font-size:11.0pt;font-family:Symbol;color:#1F497D"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">        
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I suspect one rank was trying to collect all data from other ranks. 
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">What other addition setting is needed for mumps such that it could deal with medium and large size problems?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Do you guys have similar experience on that?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Thanks,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Jinquan<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
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