[Dune] Problems using VTK cell data with Dune IndexSet

[Sascha Zelzer]

Hi again,

Sorry for the noise, the offset problem originated from my own code. I 
have the Dune IndexSet -> VTK cell label association working now.

Thanks a lot,

Sascha

On 12/27/2012 06:07 PM, Sascha Zelzer wrote:
> Hi Christian,
>
> thanks for reply! I have seen the method in the docs but couldn't
> initially think of a way to use it.
>
> Now, when iterating over codim=0 leaf entities of the created grid, the
> returned indices are ordered in the same way as the cell elements were
> added using the grid factory, which is great. But they have an offset.
> The offset in my case is neither the number of inserted vertices or
> anything I could think of. Do you know what it is? For now, I can just
> subtract the insertion index from the first leaf iterator.
>
> Thanks,
> Sascha
>
> P.S. I will try to get some time for cleaning up and sending a Dune VTK
> grid reader class.
>
> On 12/27/2012 03:57 PM, Christian Engwer wrote:
>> Hi Sascha,
>>
>>> I have VTK unstructured grid files as inputs for a FEM simulation.
>>> Using the Dune GridFactory (templated with
>>> Dune::ALUSimplexGrid<3,3>) I am able to translate the VTK grid into
>>> a Dune grid. However, I need to be able to associate the grid
>>> entities (tetrahedra) with their original VTK cell data and am
>>> having hard times to achieve that. The indices returned by
>>>
>>> duneGrid.leafView().indexSet(tetEntity)
>>>
>>> are differently ordered compared to their insertion order with the
>>> grid factory (maybe due to load balancing when creating the grid?)
>>> and I cannot find a way to create a mapping of the index set values
>>> into the original VTK cell ids (and their respective cell data).
>> There is no guarantee on the indexes returned by the grid, compared to
>> the grid file. You have to use the insertion index. You ask the grid
>> factory for the insertionIndex of a given cell.
>>
>> Dune::GridFactory::insertionIndex (const typename Codim< 0 >::Entity &entity) const
>>
>>> Did I miss something? Does anybody have a nice solution for that? If
>>> there is a solution and people are interested in such a conversion
>>> class (VTK -> Dune Grid) I would be happy to share it.
>> Adding such a reader would be nice :-)
>>
>> Christian
>>
>>> Many thanks,
>>>
>>> Sascha
>>>
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