[dune-pdelab] Dune::PDELab::ISTLBackend_NOVLP_CG_AMG_SSOR with ALUGrid

[Christian Engwer]

Hi Eike,

> that's very interesting. So far I've only been using the overlapping
> solvers on YaspGrid, but I need to move to ALUGrid for my spherical
> grid, and as far as I know I can only use the non-overlapping
> solvers there as ALUGrid does not have any overlap.

in principal yes, but it depends a littel bit on your
discretization. If you are using finite-volume for example, you only
have couplings to the face-neighbors and these are all available,
although alugrid doesn't provide a full overlap. In this case you
should be able to use an overlapping solver.

> I'll try to set up a simple test case that reproduces the problem.
> I'm using version 2.1 of Dune, so that might explain why it's not
> working for me at the moment.
> 
> Eike
> 
> Rebecca Neumann wrote:
> >Dear Eike,
> >yes, a test setup would be nice. (Do you use the dune trunk or the
> >2.1 version? I think until now only the istl trunk supports
> >NOVLP_AMG on ALUGrid.)
> >Solving a simple poisson problem with ALUGrid and
> >NOVLP_BCGS_AMG_SSOR with Q1 works fine.
> >But the NOVLP AMG is still very new and not really well tested,
> >and for ALUGrid the convergence rates are still not as good as we
> >would expect it.
> >Hopefully I will have time to explore this further in April.
> >Best Regards,
> >Rebecca
> >
> >On 27.01.2012 12:10, Markus Blatt wrote:
> >>On Fri, Jan 27, 2012 at 10:17:23AM +0000, Eike Mueller wrote:
> >>>Dear dune-/pdelab-list,
> >>>
> >>>I'm trying to use the non-overlapping ISTL backend
> >>>Dune::PDELab::ISTLBackend_NOVLP_CG_AMG_SSOR for solving a problem on
> >>>my spherical shell grid, which I implemented with ALUGrid. This
> >>>works fine in serial, but if I try to run in parallel I get the
> >>>runtime error given below [1]. I have also tried the same backend on
> >>>a non-overlapping YaspGrid (just a simple cube), where it works fine
> >>>both serially and in parallel. In addition, the ISTL backend
> >>>Dune::PDELab::ISTLBackend_NOVLP_CG_SSORk works without problems in
> >>>parallel with my ALUGrid implementation.
> >>>
> >>>Does anyone have any idea what might be going wrong here?
> >>
> >>This meas that some ghost nodes still carry the unaggregated flag even
> >>though the information about the aggregation was communicated.
> >>
> >>Which probably means that the communication interface was not setup
> >>correctly.
> >>
> >>Please provide a test case and post a bug in the pdelab bug
> >>tracker at http://users.dune-project.org/projects/dune-pdelab/issues
> >>
> >>Thanks!
> >>
> >>Markus
> >
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> >
> 
> 
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