valgrind   http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind

   Note if your HPC resource doesn't have valgrind you can still run your app 
under it on a local machine. (Big as problem as you can fit).


   Barry

> On Jul 18, 2018, at 1:20 PM, Alistair Bentley <[email protected]> wrote:
> 
> Hello all,
> 
> I'm a first time PETSc mailing list user, so I apologize in advance if this 
> is not the right mailing list for this post!
> 
> I've been using PETSc with HYPRE (BoomerAMG) as part of a Schur complement 
> block preconditioner for a time-dependent 3D Navier-Stokes equation.
> 
> Specifically, for the Schur complement approximation, I've been using PETSc's 
> selfp method (given the simulation's short time steps, this has been 
> producing reasonable results) and a single application of the default HYPRE 
> BoomerAMG.
> 
> When I run on my local machine (up to 4 processors), the simulation runs to 
> completion smoothly.  The GMRES iterations for the global system (as well as 
> the block solves) appear to scale well with h.  
> 
> Next I pushed to job to our HPC resource and ran a small job (stabilized P1P1 
> elements on 329013 tetrahedra and 56970 nodes) with 36 cores.  This time, 
> however, the simulation did not run to completion.  Rather, I began to 
> encounter the following error:
> 
> [ 6] KSPSolve() line 666 in 
> /p/home/abentle/.hashdist/tmp/petsc-mtyptrixhukj/src/ksp/ksp/interface/itfunc.c
> [ 6] KSPSolve_FGMRES() line 291 in 
> /p/home/abentle/.hashdist/tmp/petsc-mtyptrixhukj/src/ksp/ksp/impls/gmres/fgmres/fgmres.c
> [ 6] KSPFGMRESCycle() line 166 in 
> /p/home/abentle/.hashdist/tmp/petsc-mtyptrixhukj/src/ksp/ksp/impls/gmres/fgmres/fgmres.c
> [ 6] KSP_PCApply() line 275 in 
> /p/home/abentle/.hashdist/tmp/petsc-mtyptrixhukj/include/petsc/private/kspimpl.h
> [ 6] PCApply() line 458 in 
> /p/home/abentle/.hashdist/tmp/petsc-mtyptrixhukj/src/ksp/pc/interface/precon.c
> [ 6] PCApply_FieldSplit_Schur() line 900 in 
> /p/home/abentle/.hashdist/tmp/petsc-mtyptrixhukj/src/ksp/pc/impls/fieldsplit/fieldsplit.c
> [ 6] KSPSolve() line 666 in 
> /p/home/abentle/.hashdist/tmp/petsc-mtyptrixhukj/src/ksp/ksp/interface/itfunc.c
> [ 6] KSPSolve_PREONLY() line 22 in 
> /p/home/abentle/.hashdist/tmp/petsc-mtyptrixhukj/src/ksp/ksp/impls/preonly/preonly.c
> [ 6] KSP_PCApply() line 275 in 
> /p/home/abentle/.hashdist/tmp/petsc-mtyptrixhukj/include/petsc/private/kspimpl.h
> [ 6] PCApply() line 458 in 
> /p/home/abentle/.hashdist/tmp/petsc-mtyptrixhukj/src/ksp/pc/interface/precon.c
> [ 6] PCApply_HYPRE() line 351 in 
> /p/home/abentle/.hashdist/tmp/petsc-mtyptrixhukj/src/ksp/pc/impls/hypre/hypre.c
> [ 6] Error in external library
> [ 6] Error in HYPRE solver, error code 1
> 
> Unfortunately, HYPRE lists an error code1 as a generic error which does not 
> give me much to go on.  Further, while this error appears consistently, it 
> seems to occur randomly.  For instance, the error message above occurred on 
> the 6th MPI process after the simulation had reached t = 0.1.  A previous run 
> with the exact same configuration occurred on the 28th MPI process after the 
> simulation reached t = 1.1 seconds.  
> 
> I've been experimenting with different configurations to try and find a 
> stable solution, but I'm at a bit of a loss as to how to proceed.  Any 
> suggestions for moving forward would be greatly appreciated.   
> 
> Thanks!
> 
> - Alistair
> 

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