Sure, I'll probably need a few more days, though, I'm still debugging. I'll let you know Best
Andrea On May 6, 2013, at 7:43 PM, "Nystrom, William D" <wdn at lanl.gov> wrote: > Please share how that goes. I'd love to hear how it goes for you. > > Dave > > From: Andrea Lani [andrea.lani at gmail.com] > Sent: Monday, May 06, 2013 11:40 AM > To: Nystrom, William D > Cc: Paul Mullowney; petsc-dev at mcs.anl.gov; Nystrom, William D > Subject: Re: [petsc-dev] Preconditioners for GPU > > Ok, I ll try jacobi. I am also testing MHD cases by the way (interaction of > Solar wind and earth Magnetosphere, both steady and unsteady) :-) > Thx > Andrea > > On May 6, 2013, at 7:17 PM, "Nystrom, William D" <wdn at lanl.gov> wrote: > >> Andrea, >> >> Have you tried jacobi preconditioning with gpus. I've found it to work >> pretty >> well, surprisingly, and it does work in parallel with mpi. It is also worth >> seeing >> if you can use the ell or hyb matrix formats. I have seen a reduction in >> compute >> time using ell/hyb matrix formats of typically 2x up to as much as 5x when >> the >> iteration counts get large. You should also try both the cusp and cusparse >> mat_type. I've tried the above on extended mhd problems. YMMV. >> >> Having said that, I am looking forward to trying better preconditioners for >> gpus >> as they become available. But it would be interesting to see if jacobi >> preconditioning >> on the gpu solves your problem faster than your best preconditioning option >> on >> the cpu. Also, all my problems have been SPD. >> >> Dave >> >> -- >> Dave Nystrom >> LANL HPC-5 >> Phone: 505-667-7913 >> Email: wdn at lanl.gov >> Smail: Mail Stop B272 >> Group HPC-5 >> Los Alamos National Laboratory >> Los Alamos, NM 87545 >> >> From: petsc-dev-bounces at mcs.anl.gov [petsc-dev-bounces at mcs.anl.gov] on >> behalf of Andrea Lani [andrea.lani at gmail.com] >> Sent: Monday, May 06, 2013 10:52 AM >> To: Paul Mullowney >> Cc: petsc-dev at mcs.anl.gov >> Subject: Re: [petsc-dev] Preconditioners for GPU >> >> Thanks Paul! this only work for sequential cases, right? in this case, what >> performance benefit should I expect compared to a fully CPU-based version, >> if any? is anything available also for parallel runs? >> >> Andrea >> >> >> On Mon, May 6, 2013 at 5:48 PM, Paul Mullowney <paulm at txcorp.com> wrote: >> Hi Andrea, >> >> The matrix type, aijcusparse has an ILU(n) (and ICC(n) for symmetric >> problems) preconditioner. The factorization is done on the CPU. The solves >> are done on the GPU via the cusparse library. >> >> In the configure, do --download-txpetscgpu=yes >> >> I would also look at: >> >> http://www.mcs.anl.gov/petsc/petsc-dev/docs/manualpages/Mat/MATSEQAIJCUSPARSE.html >> >> for information on the aijcusparse class. >> >> -Paul >> >> >>> On Sun, May 5, 2013 at 4:26 PM, Andrea Lani <andrea.lani at gmail.com> >>> wrote: >>> Thanks, Matt! Let me re-iterate on the question... are there other >>> available preconditioners already ported to GPU, which are not based on AMG >>> (which is typically not suitable for my convection-dominated CFD problems) >>> and apart from BICGSTABCUSP? >>> >>> I believe that the txpetscgpu package has triangular solves for the GPU. >>> >>> BiCGStab is a Krylov method. >>> >>> Matt >>> >>> Andrea >>> >>> >>> On May 5, 2013, at 9:53 PM, Matthew Knepley <knepley at gmail.com> wrote: >>> >>>> On Sun, May 5, 2013 at 2:48 PM, Andrea Lani <andrea.lani at gmail.com> >>>> wrote: >>>> Dear Developers, >>>> >>>> Could you please tell me the list of preconditioners for non-symmetric >>>> systems fully ported to multi-GPU and available in the current development >>>> version? >>>> >>>> In my opinion, there are no truly multi-GPU preconditioners anywhere. We >>>> can imagine them, like AMG with Chebychev smoothers, but >>>> I have not really seen any of them reliably work. The CUSP SA-AMG is the >>>> closest one in this category, and Steve Dalton is working on >>>> it this summer at ANL. >>>> >>>> Matt >>>> >>>> Thanks in advance >>>> >>>> Andrea >>>> >>>> >>>> >>>> -- >>>> What most experimenters take for granted before they begin their >>>> experiments is infinitely more interesting than any results to which their >>>> experiments lead. >>>> -- Norbert Wiener >>> >>> >>> >>> -- >>> What most experimenters take for granted before they begin their >>> experiments is infinitely more interesting than any results to which their >>> experiments lead. >>> -- Norbert Wiener >> >> >> >> >> -- >> Dr. Andrea Lani >> >> Senior Research Engineer, PhD >> Aeronautics & Aerospace dept., CFD group >> Von Karman Institute for Fluid Dynamics >> Chausse de Waterloo 72, >> B-1640, Rhode-Saint-Genese, Belgium >> fax : +32-2-3599600 >> work : +32-2-3599769 >> lani at vki.ac.be > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-dev/attachments/20130506/6833eb0c/attachment-0001.html>
