[Dune] YaspGrid refinement question

[Christian May]

YASP's adapt indeed does a globalRefine independent of any markers. Are 
there any plans to fix that behaviour soon or which alternative grid can 
you recommend that supports parallelization and refinement?

Cheers
Christian

On Tue, 3 Mar 2009, Martin Nolte wrote:

> The method preAdapt returns true if there is an entity that might be caorsened.
> This is also clearly stated in the documentation of Dune::Grid.
>
> So, if you only mark entities for refinement, the method preAdapt() should
> return false. You can find out whether entities have been refined by the return
> value of adapt().
>
> This means the implementation in YaspGrid does exactly what it should do, since
> YaspGrid does not support coarsening.
>
> Cheers,
>
> Martin
>
>
> Andreas Dedner wrote:
>> I far as I can see it, this is a bug in YASP.
>> I understand that preAdapt only returns false if
>> a call to adapt will lead to no modification of the
>> grid. The default implementation returns false and that
>> is used in YASP. The default implementation for adapt
>> is of course to do nothing - so this is consistent.
>> Yhe implementation of adapt on YASP is to call a
>> globalRefine - independent of any marker or anything
>> of that sort.
>> I think that this is not intuitive behaviour and can
>> be quite problematic in adaptive computations since
>> the grid is globally refined each time adapt is called.
>> I had assumed that a grid with no local
>> adaptation (as given by the Capabilities) does nothing
>> if adapt is called.
>> But prehaps I misundersood the code...
>> Andreas
>> On Tue, 3 Mar 2009 17:15:49 +0100 (CET)
>>  Christian May <cmay at phys.ethz.ch> wrote:
>>> Dear developers,
>>>
>>> as I understand it, preAdapt() should return true if an
>>> entity of the grid has been marked for refinement by the
>>> mark() method.
>>> In the attached program, all entities are marked.
>>> However, if I run it, it always returns false.
>>> Can you please give me a hint?
>>>
>>> Thanks
>>> Christian
>>>
>>>
>>>
>> ---------------------------------------------------------------------------
>>> Christian May
>>>
>>> ETH Zurich
>>> Institute for Theoretical Physics, HIT K 31.5
>>> CH-8093 Zurich, Switzerland
>>>
>>> Tel: + 41 44 633 79 61
>>> Fax: + 41 44 633 11 15
>>>
>>> Email: cmay at itp.phys.ethz.ch
>>>
>>
>>
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>
> -- 
> Martin Nolte <nolte at mathematik.uni-freiburg.de>
>
> Universit?t Freiburg                                   phone: +49-761-203-5642
> Abteilung f?r angewandte Mathematik                    fax:   +49-761-203-5632
> Hermann-Herder-Stra?e 10
> 79104 Freiburg, Germany
>
>
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>

---------------------------------------------------------------------------
Christian May

ETH Zurich
Institute for Theoretical Physics, HIT K 31.5
CH-8093 Zurich, Switzerland

Tel: + 41 44 633 79 61
Fax: + 41 44 633 11 15

Email: cmay at itp.phys.ethz.ch