[Dune] DUNE advection w/ periodic BC w/ RK4 ?

[Oliver Sander]

Hi Theresa,

if you don't like the YaspGrid approach to periodicity you may want
to check out

   https://gitlab.dune-project.org/staging/dune-functions/-/merge_requests/263

There, you can select groups of degrees of freedom, and they
will become 'unified'.

Best,
Oliver

On 04.12.20 17:09, Peter Bastian wrote:
> Dear Theresa,
> 
> The standard explicit RK4 method is implemented in the class RK4Parameter <https://www.dune-project.org/doxygen/pdelab/master/classDune_1_1PDELab_1_1RK4Parameter.html>
> in PDELab (it merely contains
> the entries of the Butcher Tableau, so you could easily add other methods as well).
> Sorry for answering this here, as it is actually the dune list and not a pdelab list.
> 
> Periodic boundary conditions on YaspGrid need to be implemented "in a parallel setting",
> i.e. halo cells are added in the periodic directions and a communication steps transports
> the solution from boundary to boundary. But I did not try this for a long time ...
> 
> Which disretization scheme did you intend to use?
> 
> Best regards,
> 
> Peter
> 
> Am 04.12.20 um 16:11 schrieb Theresa Pollinger:
>>
>> Dear DUNE developers,
>>
>> as you may know, we are using DUNE to run FEM with the sparse grid combination technique, via coupling to our code DisCoTec [0].
>>
>> Now for another project, we were simulating a pure advection problem with another FEM code, which returned rather unexpected results. Now I wanted to turn the exact same advection problem into a DUNE problem to validate the results, but it turns out that this is quite hard. Two things I am struggling with:
>>
>> - how do you set periodic boundary conditions in all directions? So far I only found this old answer [1], and a test using YaspGrid looks very much like periodicity is only set in one dimension, even if I supply an all-true argument `periodic`.
>>
>> - What is the proper way to use a Runge-Kutta 4th-order scheme in DUNE? AFAICT, pdelab only implements up to order 3 RK methods [2]?
>>
>> Maybe you could let me know if there are people who have already implemented those things.
>>
>> Best,
>>
>> Theresa
>>
>>
>> [0] https://github.com/SGpp/DisCoTec
>>
>> [1] https://lists.dune-project.org/pipermail/dune-pdelab/2011-October/000212.html <https://lists.dune-project.org/pipermail/dune-pdelab/2011-October/000212.html>
>>
>> [2] https://github.com/dune-project/dune-pdelab/blob/master/dune/pdelab/instationary/onestepparameter.hh
>>
>> -- 
>>
>> Theresa Pollinger
>>
>> Universität Stuttgart
>> Institut für Parallele und Verteilte Systeme
>> Simulation Software Engineering
>>
>> Universitätsstr. 38
>> 70569 Stuttgart
>>
>> Phone: +49 711 685 60921
>>
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> 
> 
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