[Dune] Problems using VTK cell data with Dune IndexSet

[Sascha Zelzer]

Okay, I got the mapping working. It seems that the GridFactory ALUGrid 
implementation communicates the insertion indices to the other processes.

Sorry again for the spam, I am new to mpi and parallel dune development 
and have to meet a deadline for getting some results soon...

- Sascha

On 12/28/2012 01:29 PM, Sascha Zelzer wrote:
> Hi,
>
> I am now trying to do a parallel version of my Dune program. The grid
> factory for a ALUGrid only allows insertions on rank=0 so I am having
> difficulties creating a proper mapping from grid entities to their
> insertion index in order to map them to their respective vtk cell data.
>
> Any ideas how to get the insertion index on processes with rank != 0
> would be great.
>
> Thanks,
> Sascha
>
>
> 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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