<html><body bgcolor="#FFFFFF"><div>Ok, thanks.</div><div><br></div><div>In fact, I have another major problem: when running on multi-GPU with PETSc my results are totally inconsistent compared to a single GPU .</div><div><br></div><div>In my code, for now, I'm assuming a 1-1 correspondence between CPU and GPU: I run on 8 cores and 8 GPUs (4 K10). How can I enforce this in the PETSc solver? Is it automatically done or do I have to specify some options?</div><div><br></div><div>Thanks again</div><div><br></div><div>Andrea</div><div><br></div><div><br></div><div><br></div><div><br><br>On Jan 17, 2014, at 8:48 PM, Matthew Knepley <<a href="mailto:knepley@gmail.com">knepley@gmail.com</a>> wrote:<br><br></div><div></div><blockquote type="cite"><div><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Fri, Jan 17, 2014 at 1:29 PM, Andrea Lani <span dir="ltr"><<a href="mailto:andrea.lani@gmail.com" target="_blank"><a href="mailto:andrea.lani@gmail.com">andrea.lani@gmail.com</a></a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div><div></div>Dear Devs,<br></div><br>is the PCBJACOBI solver fully ported to GPU in the latest petsc-dev version? if not, is there any intention to do so in the near future? <br>
<br>I have a convection-dominated (with strong discontinuities in the flow field) MHD problem where PCASM and PCBJACOBI both work fine with KSPGMRES.</div></blockquote><div><br></div><div>These can be done on the GPU, but the key is the inner PC. Right now, we have no ILU0 or equivalent, which I think is what</div>
<div>you want. You can try the AMG variants, but I am guessing they would not be great for convection dominated flow.</div><div><br></div><div>Maybe Karl has a better suggestion?</div><div><br></div><div> Thanks,</div><div>
<br></div><div> Matt</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div><div>Looking for a speedup in my code (which is using a petsc-dev version about two-months old), the only GPU alternative I found was PCJACOBI. This is indeed considerably faster on GPU, but does not converge (neither does, consistently, its CPU counterpart) if not for a few iterations before blowing up. Any other alternative for GPU-based preconditioners or solvers worth trying at the moment?<br>
<br></div><div>Thanks in advance for your advice<span class="HOEnZb"><font color="#888888"><br><br></font></span></div><span class="HOEnZb"><font color="#888888"><div>Andrea<br></div><div><br><br clear="all"></div><div><div>
<br>-- <br><span style="color:rgb(102,102,102)">Dr. Andrea Lani </span><br style="color:rgb(102,102,102)">
<span style="color:rgb(102,102,102)">Senior Research Engineer, PhD</span><br style="color:rgb(102,102,102)"><span style="color:rgb(102,102,102)">Aeronautics & Aerospace dept., CFD group </span><span style="color:rgb(102,102,102)"><br>
Von Karman Institute for Fluid Dynamics </span><br style="color:rgb(102,102,102)"><span style="color:rgb(102,102,102)">
Chausse de Waterloo 72, </span><br style="color:rgb(102,102,102)"><span style="color:rgb(102,102,102)">B-1640, Rhode-Saint-Genese, Belgium</span><span style="color:rgb(102,102,102)"><br>fax : <a href="tel:%2B32-2-3599600" value="+3223599600" target="_blank">+32-2-3599600</a> </span><br style="color:rgb(102,102,102)">
<span style="color:rgb(153,153,153)"><span style="color:rgb(102,102,102)">
work : <a href="tel:%2B32-2-3599769" value="+3223599769" target="_blank">+32-2-3599769</a> </span> <span style=""></span></span><u style="background-color:rgb(51,51,255);color:rgb(153,153,153)"><br><span style="background-color:rgb(255,255,255);color:rgb(0,0,153)"><a href="mailto:lani@vki.ac.be" target="_blank"><a href="mailto:lani@vki.ac.be">lani@vki.ac.be</a></a></span></u>
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</blockquote></div><br><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
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