[petsc-dev] GPU preconditioners

[Andrea Lani]

Ok, thanks.

In fact, I have another major problem: when running on multi-GPU with PETSc my results are totally inconsistent compared to a single GPU  .

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?

Thanks again

Andrea





On Jan 17, 2014, at 8:48 PM, Matthew Knepley <knepley at gmail.com> wrote:

> On Fri, Jan 17, 2014 at 1:29 PM, Andrea Lani <andrea.lani at gmail.com> wrote:
> Dear Devs,
> 
> 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?  
> 
> I have a convection-dominated (with strong discontinuities in the flow field) MHD problem where PCASM and PCBJACOBI both work fine with KSPGMRES.
> 
> 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
> you want. You can try the AMG variants, but I am guessing they would not be great for convection dominated flow.
> 
> Maybe Karl has a better suggestion?
> 
>   Thanks,
> 
>      Matt
>  
> 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?
> 
> Thanks in advance for your advice
> 
> Andrea
> 
> 
> 
> -- 
> 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
> 
> 
> 
> -- 
> 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
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