On Tue, Oct 20, 2009 at 9:52 AM, <span dir="ltr"><<a href="mailto:jarunan@ascomp.ch">jarunan@ascomp.ch</a>></span> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Hello,<br>
<br>
I would like to know some information about GMRES performance in PETSc if you have any experience.<br>
<br>
I am running a parallel test case(9300 cells) comparing cpu time using by solvers in Petsc. While BICGSTAB was doing 0.9 sec, GMRES 15 sec with the same preconditioner(Additive Schwarz). I did not expect that GMRES would be that much slower. Everything is default.<br>
</blockquote><div><br>I ssume you mean it takes many more iterates. This is certainly possible.<br> </div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Please share your experiences, how the performance of solvers are in your test cases. Which option I should set to improve GMRES performance? Is there the best combination of Preconditioner and solver?<br></blockquote><div>
<br>Solvers are highly problem dependent. There is no black box solution.<br><br> Matt<br> </div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Thank you very much<br>
Jarunan<br>
<br>
-- <br>
Jarunan Panyasantisuk<br>
Development Engineer<br>
ASCOMP GmbH, Technoparkstr. 1<br>
CH-8005 Zurich, Switzerland<br>
Phone : +41 44 445 4072<br>
Fax : +41 44 445 4075<br>
E-mail: <a href="mailto:jarunan@ascomp.ch" target="_blank">jarunan@ascomp.ch</a><br>
<a href="http://www.ascomp.ch" target="_blank">www.ascomp.ch</a><br>
</blockquote></div><br><br clear="all"><br>-- <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>