[Dune-devel] Semantics of overlapSize and ghostSize

[Oliver Sander]

Hi Peter,

that's all fine, but it is not the answer to my question.

Looking at the mail thread that Bernd sent (thanks!), it seems like nobody knows what the
codim parameter is supposed to be good for, and it is generally ignored.

http://lists.dune-project.org/pipermail/dune-devel/2013-November/000648.html

Thanks,
Oliver

On 03.08.2016 12:18, Peter Bastian wrote:
> Dear Oliver,
> 
> what about the definition in the dune grid paper (part 1)?
> 
> My understanding is this:
> 
> Codim 0:
> - interior forms a partitioning of the set of all elements
> - overlap are elements to form a set of overlapping subdomains in the
> sense of domain decomposition methods (I think there is no strict definition)
> - ghost is similar but typically ghost elements only serve as the minimum
> additional elements needed in addition to interior elements
> - A grid might have only interior elements(e.g. Yasp), interior+overlap (e.g. Yasp),
> interior+ghost (UG, ALU), interior+overlap+ghost(none)
> 
> Codim>0:
> - For any codim 0 entity all subentities of codim>0 are also stored on that process
> - In general, a codim>0 entity has the same partition type as the codim 0 entity that it is part of
> - since this may be non-unique, two additional partition types exist: border and front.
> - border are entites on the boundary of interior to X where X is either overlap or ghost
> - front are entites on the boundary from overlap to ghost
> 
> Probably this is still ambiguous at some places, but it should give the general idea.
> 
> -- Peter
> 
> 
> 
> Am 03.08.16 um 11:14 schrieb Bernd Flemisch:
>> Hi Oliver,
>>
>> there has been some discussion on the dune-devel list, see for example
>> http://lists.dune-project.org/pipermail/dune-devel/2013-November/000648.html
>>
>> People agreed that this should be discussed in a meeting or a small task force, but I am not aware of that this actually happened.
>>
>> Kind regards
>> Bernd
>>
>> On 08/03/2016 11:00 AM, Oliver Sander wrote:
>>> Dear Dune experts,
>>>
>>> I am trying to explain the meaning of the overlapSize and ghostSize methods to someone,
>>> and I've come to realize that I don't know it myself.  I know it means something like
>>> "the thickness of the overlap/ghost layers, measured in terms of elements", but is there
>>> anything more precise?  In particular, boths methods take integer arguments 'codim',
>>> but I have no idea of how that argument is supposed to influence the result.  What is
>>> the most precise definition of the semantics of overlapSize and ghostSize that you know of?
>>>
>>> Thanks,
>>> Oliver
>>>
>>>
>>>
>>> _______________________________________________
>>> Dune-devel mailing list
>>> Dune-devel at dune-project.org
>>> http://lists.dune-project.org/mailman/listinfo/dune-devel
>>
>>
>> -- 
>> _______________________________________________________________
>>
>> Bernd Flemisch                         phone: +49 711 685 69162
>> IWS, Universität Stuttgart             fax:   +49 711 685 60430
>> Pfaffenwaldring 61            email: bernd at iws.uni-stuttgart.de
>> D-70569 Stuttgart            url: www.hydrosys.uni-stuttgart.de
>> _______________________________________________________________
>>
>>
>> _______________________________________________
>> Dune-devel mailing list
>> Dune-devel at dune-project.org
>> http://lists.dune-project.org/mailman/listinfo/dune-devel
> 
> 
> -- 
> ------------------------------------------------------------
> Peter Bastian
> Interdisziplinäres Zentrum für Wissenschaftliches Rechnen
> Universität Heidelberg
> Im Neuenheimer Feld 205 (Mathematikon) Raum 1/401
> D-69120 Heidelberg
> Tel: 0049 (0) 6221 5414517
> Fax: 0049 (0) 6221 548884
> email: peter.bastian at iwr.uni-heidelberg.de
> web: http://conan.iwr.uni-heidelberg.de/people/peter/
> 
> 
> 
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