On Thu, Dec 15, 2011 at 10:23 AM, Ravi Kannan <span dir="ltr"><<a href="mailto:rxk@cfdrc.com">rxk@cfdrc.com</a>></span> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div lang="EN-US" link="blue" vlink="purple" style="word-wrap:break-word"><div><p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Dear All,<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p><p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1f497d">This is Ravi Kannan from CFD Research Corporation. Recently, we are experimenting with the BoomerAMG preconditioner for some “stiff” CFD problems. In that regard, all the other standard solver-preconditioner combinations failed for the current CFD problem. The boomer is the only one which is able to provide with “converged” solutions.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p><p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1f497d">We noticed that the scalability of this boomer preconditioner is really poor. For instance, even with a cell size of 2 million, we cannot scale to even 16 partitions (in contrast, the other solver-preconditioner combinations like the BI-CGS/BJacobi gave good enough scalability).<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p><p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Are we missing something? Do we need to use a more latest version of boomer?</span></p>
</div></div></blockquote><div><br></div><div>Have you tried -pc_type gamg in petsc-dev?</div><div><br></div><div>  Matt</div><div> <span class="Apple-style-span" style="color:rgb(31,73,125);font-family:Calibri,sans-serif;font-size:19px"> </span></div>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div lang="EN-US" link="blue" vlink="purple" style="word-wrap:break-word"><div><p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Thanks,<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Ravi. <u></u><u></u></span></p><p class="MsoNormal"><font class="Apple-style-span" color="#1f497d" face="Calibri, sans-serif"><span class="Apple-style-span" style="font-size:19px"><br>
</span></font></p></div></div></blockquote></div><br clear="all"><div><br></div>-- <br>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<br>