On Tue, Jun 16, 2009 at 12:38 PM, xiaoyin ji <span dir="ltr"><<a href="mailto:sapphire.jxy@gmail.com">sapphire.jxy@gmail.com</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;">
Hi there,<br>
<br>
I'm using PETSc MATMPIAIJ and ksp solver. It seems that PETSc will run<br>
obviously faster if I set the number of CPUs close to the number of<br>
computer nodes in the job file. By default MPIAIJ matrix is stored in<br>
different processors and ksp solver will communicate for each step,<br>
however since on each node several CPUs share the same memory while<br>
ksp may still try to communicate through network card, this may mess<br>
up a bit. Is there any way to detect which CPUs are sharing the same<br>
memory? Thanks a lot.</blockquote><div><br>The interface for this is mpirun or the job submission mechanism.<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;">
<br>
Best,<br>
<font color="#888888">Xiaoyin Ji<br>
</font></blockquote></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>