[Dune] inconsistency with intersection methods

[Mario Ohlberger]

Hallo Peter,

nach einer kleinen Diskussion mit Robert, sind wir zu der Meinung
gekommen, dass wir zwar laengerfristig die unten angegebene Eigenschaft
wollen, dass wir dies aber nicht mehr fuer 1.0 angehen! Schliesslich
wurde in Freiburg ja der TwistProvider programmiert, und somit tut
jetzt ja alles. Die Implementierung der entsprechenden Abbildungen
fuer Unstrukturierte Gitter ist eben doch aufwendig und wir haben zur
Zeit keine Kapazitaeteten dies noch vor 1.0 umzustellen.

Dennoch waere die unten angegebene Eigenschaft eigentlich das richtig
Konzept.

Gruss Mario.



Peter Bastian wrote:
> Dear Sreejith,
> 
> I think you are correct that there is an inconsistency in the
> implementation. What is necessary is the following condition:
> 
> Let is be an IntersectionIterator with is.neighbor()==true and xi a
> point in the local coordinate system of the intersection then
> 
> is.intersectionSelfLocal.global(xi) ==
> is.intersectionNeighborLocal.global(xi) == is.intersectionGlobal.global(xi)
> 
> This condition has also been added by Mario in the theory part of the
> Dune paper.
> 
> Question: Do we all agree on this (I do!).
> 
> Best,
> 
> Peter
> 
> 
> Sreejith Pulloor Kuttanikkad wrote:
> 
>> Duneler,
>>
>>  
>> I am still not very clear on the point that when evaluating the global
>> coordinate of an intersection point from either side how one can get
>> different global value for same point ( i think the orientation
>> matters here.. that means one should be aware of how the orintation is
>> defined locally.. )
>> I would assume that when finding a global coordinate of an
>> intersection point from both sides of the intersection one should get
>> the same value irrespective of orientation.
>> However when i use UG and Alberta grid i do not get the same
>> value whereas with Sgrid and Yaspgrid I get same value. I feel like
>> there is some inconsistency in the implementation of intersection
>> methods in
>> different grids. (i dont know if i understood something wrongly)
>>
>> thanks,
>> Sreejith
>>
> 

-- 
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  Dr. Mario Ohlberger		     Tel.: +49-761/203-5635
  Abteilung f. Angewandte Mathematik Fax.: +49-761/203-5632	
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  E-Mail: mario at mathematik.uni-freiburg.de
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