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

[Timo Heister]

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:
> https://urldefense.proofpoint.com/v2/url?u=http-3A__www.math.colostate.edu_-7Ebangerth_&d=DwIGaQ&c=Ngd-ta5yRYsqeUsEDgxhcqsYYY1Xs5ogLxWPA_2Wlc4&r=R5lvg9JC99XvuTgScgbY_QFS80R7PEA2q0EPwDy7VQw&m=1CPipUrsDEc8vNcA_TcedJ0x0o2_P13lFm64C-FBXT0&s=ZgGNuNrQpnnpoawynmntW-GtvrVw3NaWZP2N39W1MlY&e=
> _______________________________________________
> Aspect-devel mailing list
> Aspect-devel at geodynamics.org
> https://urldefense.proofpoint.com/v2/url?u=http-3A__lists.geodynamics.org_cgi-2Dbin_mailman_listinfo_aspect-2Ddevel&d=DwIGaQ&c=Ngd-ta5yRYsqeUsEDgxhcqsYYY1Xs5ogLxWPA_2Wlc4&r=R5lvg9JC99XvuTgScgbY_QFS80R7PEA2q0EPwDy7VQw&m=1CPipUrsDEc8vNcA_TcedJ0x0o2_P13lFm64C-FBXT0&s=fmCU8C8oOe_MbSjnU2Lx7z2gzkynBVc9srkTeV5LN6s&e=



-- 
Timo Heister
http://www.math.clemson.edu/~heister/