[Paraview] Multipiece Structured Dataset questions

[Erik Wilson]

Many thanks for the information, this is exactly what I was looking for.

Cheers,
  -Erik


On 03/05/2012 12:42 PM, David E DeMarle wrote:
> I agree with John.
>
> See VTK/Parallel/vtkVPICReader.cxx for an example.
>
> David E DeMarle
> Kitware, Inc.
> R&D Engineer
> 21 Corporate Drive
> Clifton Park, NY 12065-8662
> Phone: 518-881-4909
>
>
>
> On Mon, Mar 5, 2012 at 2:34 PM, Biddiscombe, John A.<biddisco at cscs.ch>  wrote:
>> Erik,
>>
>> I'd try 3, but instead of using sub extents (which I might have misunderstood what that implies), I'd use the TableExtentTranslator so that each piece is mapped to the already computed extents that you saved your data using.
>>
>> Essentially, you already have a mapping between pieces and extents, you can set these up in the TableExtentTranslator and then when the downstream code requests extents, they'll be calculated based on the values you've setup. Even though the pipeline requests a structured VTK_3D_EXTENT from your reader, the values in that Extent are calculated based on the mpi rank (piece number), so by fooling it with a custom extent translator, all should work (note that I say should, because I've used my own custom extent translator, but not the table extent trans so I'm guessing - when Dave DeM reads this he'll either put us right, or possibly concur).
>>
>> JB
>>
>>
>>
>> -----Original Message-----
>> From: paraview-bounces at paraview.org [mailto:paraview-bounces at paraview.org] On Behalf Of Erik Wilson
>> Sent: 05 March 2012 17:22
>> To: paraview at paraview.org
>> Subject: [Paraview] Multipiece Structured Dataset questions
>>
>>
>> Hello all,
>>
>> I am attempting to develop a Paraview plugin to read in parallel a multipiece structured dataset through a custom I/O library. Since our data is already broken up into pieces it would be nice to use a grid type which has a DATA_EXTENT_TYPE of VTK_PIECES_EXTENT, otherwise when using VTK_3D_EXTENT extra code will need to be created to calculate and subtract sub-extents such as seen in vtkXMLPStructuredDataReader. There are three different options I am considering for developing this reader:
>>
>> 1) Use an Unstructured Grid
>>
>> Simply translate our structured grid into a vtkUnstructuredGrid using Hexahedron cells. Will unstructured grids be as efficient as structured grids for operations such as cut planes and streamlines, or are there any efficiency disadvantages to using unstructured grids in general?
>>
>> 2) Subclass Structured Grid
>>
>> Create a subclass of vtkStructuredGrid which uses has a DATA_EXTENT_TYPE of VTK_PIECES_EXTENT. Is this even feasible, or any other issues?
>>
>> 3) Use a Structured Grid
>>
>> Just write the code to calculate and subtract 3d sub-extents, better than above options?
>>
>>
>> Any feedback or advice is greatly appreciated.
>>
>> Thanks,
>>   -Erik
>>
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