[petsc-users] unsure about ex19 test results

[Matthew Knepley]

On Mon, Dec 5, 2011 at 8:17 AM, Dominik Szczerba <dominik at itis.ethz.ch>wrote:

> I am on a Cray system, where I have configured and built petsc 3.2 p5
> myself, only using the vendor provided mpi, all the other packages
> (parmetis, hypre, mumps) are built with --download-package. "Make ...
> test" does not work here to verify the correct build because users do
> not have access to mpiexec. So I do the test by hand, and I am unsure
> about what I am getting. When executing the test ex19 with the
> system's scheduler I get this output:
>
> lid velocity = 0.0204082, prandtl # = 1, grashof # = 1
> Number of Newton iterations = 2
> lid velocity = 0.0204082, prandtl # = 1, grashof # = 1
> Number of Newton iterations = 2
>
> It's quite different from the expected output in ex19_1.testout:
>
> lid velocity = 0.0016, prandtl # = 1, grashof # = 1
> Number of Newton iterations = 2
> lid velocity = 0.0016, prandtl # = 1, grashof # = 1
> Number of Newton iterations = 2
>

Are you running with the right options?  -dmmg_nlevels 4 -snes_monitor_short

  Matt


> Does it mean that I have screwed up the build somehow, or is this
> somehow the effect of the batching system, or just numerical
> uncertainty due to the parallel computation? Note: I get the same
> result with 1 and a few MPI processes.
>
> Many thanks for any ideas.
>
> Dominik
>



-- 
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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