[aspect-devel] Weird pressure with periodic BC's + direct solver?

[Jonathan Perry-Houts]

Ahh. That explains it. I was running in Release mode so I never saw that 
error.

Should the Assert at source/simulator/nullspace.cc:243 be an AssertThrow 
instead?

On 09/13/2017 05:56 AM, Timo Heister wrote:
> Jonathan,
> 
> I am getting this error when running your prm:
> --------------------------------------------------------
> An error occurred in line <244> of file
> <../source/simulator/nullspace.cc> in function
>      void aspect::Simulator<dim>::remove_net_linear_momentum(bool,
> aspect::LinearAlgebra::BlockVector&,
> aspect::LinearAlgebra::BlockVector&) [with int dim = 2,
> aspect::LinearAlgebra::BlockVector =
> dealii::TrilinosWrappers::MPI::BlockVector]
> The violated condition was:
>      introspection.block_indices.velocities !=
> introspection.block_indices.pressure
> Additional information:
>      You are trying to use functionality in deal.II that is currently
> not implemented. In many cases, this indicates that there simply
> didn't appear much of a need for it, or that the author of the
> original code did not have the time to implement a particular case. If
> you hit this exception, it is therefore worth the time to look into
> the code to find out whether you may be able to implement the missing
> functionality. If you do, please consider providing a patch to the
> deal.II development sources (see the deal.II website on how to
> contribute).
> 
> Stacktrace:
> -----------
> #0  ./build/aspect:
> aspect::Simulator<2>::remove_net_linear_momentum(bool,
> dealii::TrilinosWrappers::MPI::BlockVector&,
> dealii::TrilinosWrappers::MPI::BlockVector&)
> #1  ./build/aspect:
> aspect::Simulator<2>::remove_nullspace(dealii::TrilinosWrappers::MPI::BlockVector&,
> dealii::TrilinosWrappers::MPI::BlockVector&)
> #2  ./build/aspect: aspect::Simulator<2>::solve_stokes()
> #3  ./build/aspect: aspect::Simulator<2>::solve_timestep()
> #4  ./build/aspect: aspect::Simulator<2>::run()
> #5  ./build/aspect: main
> --------------------------------------------------------
> 
> On Tue, Sep 12, 2017 at 7:38 PM, Wolfgang Bangerth
> <bangerth at colostate.edu> wrote:
>> On 09/06/2017 11:38 PM, Jonathan Perry-Houts wrote:
>>>
>>> Thanks for the suggestion Wolfgang! It does indeed only show up at hanging
>>> nodes (figure attached). And it apparently only happens with both the direct
>>> solver, and 'remove null space' enabled at the same time (also attached).
>>>
>>> When those two options are both enabled the pressure solution is zero
>>> everywhere, but gets these little (~ 1e-6) jitters at hanging nodes.
>>> Definitely sounds like a ConstraintsMatrix problem.
>>
>>
>> Can you compare the direct solver/iterative solver code paths in solver.cc
>> to see whether we may accidentally forget to call something like
>> constraints.distribute(...) on the solution vector if we use the direct
>> solver?
>>
>> Best
>>   W.
>>
>> --
>> ------------------------------------------------------------------------
>> Wolfgang Bangerth          email:                 bangerth at colostate.edu
>>                             www:
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> 
> 
> 

-- 
Jonathan Perry-Houts
Ph.D. Candidate
Department of Earth Sciences
1272 University of Oregon
Eugene, OR 97403-1272