[petsc-dev] [issue1595] Issues of limited number of MPI communicators when having many instances of hypre boomerAMG with Moose

[Smith, Barry F.]

> On Apr 3, 2018, at 4:30 PM, Li, Ruipeng <li50 at llnl.gov> wrote:
> 
> Hi, Fande,
> 
> "For instance, if an application has multiple fields and each field will be solved by a HYPRE solver,  then we end up with  multiple hypre solves. The multiple hypre solves are not run simultaneously, instead, it will be run one-by-one. If we assign the same communicator to the multiple hypre solves, any potential tag conflict?"
> 
> In this scenario, is just the solve phase of BoomerAMG one after another, or also the setup of AMG? Since BoomerAMG takes the communicator from the A matrix, if the entire hypre solve (setup + solve) is serial, there should be no conflicts.

    It would be mostly be 

setup on first matrix solve on first matrix
setup on second matrix solve on second matrix
.....
solve on first matrix
solve on second matrix
...
setup on first matrix solve on first matrix
setup on second matrix solve on second matrix
.....
solve on first matrix
solve on second matrix
...

  Barry


> 
> -Ruipeng
> 
> . -- .- .. .-.. / ..-. .-. --- -- / .-. ..- .. .--. . -. --. / .-.. ..
> Ruipeng Li
> Center for Applied Scientific Computing
> Lawrence Livermore National Laboratory
> P.O. Box 808, L-561
> Livermore, CA 94551
> phone - (925) 422-6037,  email - li50 at llnl.gov
> 
> 
> ________________________________________
> From: Kong, Fande <fande.kong at inl.gov>
> Sent: Tuesday, April 3, 2018 1:34 PM
> To: hypre-support
> Cc: Barry Smith; Derek Gaston; Li, Ruipeng; Osei-Kuffuor, Daniel; For users of the development version of PETSc; Schroder, Jacob B.; tzanio at llnl.gov; umyang at llnl.gov; Wang, Lu
> Subject: Re: [issue1595] Issues of limited number of MPI communicators when having many instances of hypre boomerAMG with Moose
> 
> 
> 
> On Tue, Apr 3, 2018 at 2:12 PM, Rob Falgout hypre Tracker <hypre-support at llnl.gov<mailto:hypre-support at llnl.gov>> wrote:
> 
> Rob Falgout <rfalgout at llnl.gov<mailto:rfalgout at llnl.gov>> added the comment:
> 
> Hi Barry,
> 
> Can you explain the scenario where multiple hypre solves would be working in parallel with the same communicator?  Thanks!
> 
> Hi Rob,
> 
> For instance, if an application has multiple fields and each field will be solved by a HYPRE solver,  then we end up with  multiple hypre solves. The multiple hypre solves are not run simultaneously, instead, it will be run one-by-one. If we assign the same communicator to the multiple hypre solves, any potential tag conflict?
> 
> Fande,
> 
> 
> 
> -Rob
> 
> ____________________________________________
> hypre Issue Tracker <hypre-support at llnl.gov<mailto:hypre-support at llnl.gov>>
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