[petsc-users] Is OpenMP still available for PETSc?

[Matthew Knepley]

On Mon, Jul 3, 2017 at 9:23 AM, Damian Kaliszan <damian at man.poznan.pl>
wrote:

> Hi,
>
>
> >> 1) You can call Bcast on PETSC_COMM_WORLD
>
> To  be  honest  I  can't find Bcast method in petsc4py.PETSc.Comm (I'm
> using petsc4py)
>
> >> 2) If you are using WORLD, the number of iterates will be the same on
> each process since iteration is collective.
>
> Yes,  this  is  how  it  should  be.  But  what  I noticed is that for
> different  --cpus-per-task  numbers  in  slurm  script I get different
> number  of  solver iterations which is in turn related to timings. The
> imparity    is    huge.  For  example  for   some configurations where
> --cpus-per-task=1 I receive 900
> iterations and  for --cpus-per-task=2 I receive valid number of 100.000
> which is set as max
> iter number set when setting solver tolerances.
>

I am trying to understand what you are saying. You mean that you make 2
different runs and get a different
number of iterates with a KSP? In order to answer questions about
convergence, we need to see the output
of

  -ksp_view -ksp_monitor_true_residual -ksp_converged_reason

for all cases.

  Thanks,

     Matt


> Best,
> Damian
>
>


-- 
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

http://www.caam.rice.edu/~mk51/
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