[Paraview-developers] Parallel structured grid reader doesn"t produce subextent

[Utkarsh Ayachit]

Use * outInfo->Set(CAN_PRODUCE_SUB_EXTENT(), 1) * instead of
*outInfo->Set(CAN_HANDLE_PIECE_REQUEST(),1)*. Alternatively, you can create
a *vtkExtentTranslator* instance yourself in RequestData to convert
*UPDATE_PIECE_NUMBER(), UPDATE_NUMBER_OF_PIECES()
* to sub-extents in *RequestData*.

The latter may be better since it looks like your reader is producing a
vtkMultiBlockDataSet. If I remember correctly, the extent-based request
only works for structured datasets eg. vtkStructuredGrid, vtkImageData etc.

Utkarsh

On Tue, May 30, 2017 at 10:08 AM, Mizael Moser, Markus Klaus <
markus.moser at rwth-aachen.de> wrote:

> Dear ParaView developers,
>
> I'm having trouble to parallelize my ParaView reader plugin. I want to
> read HDF5 files and the grid is a structured grid. The plugin works
> perfectly fine if run in serial, and if i run it in parallel the solution
> is also correct but instead of dividing the dataset in x subsets, it reads
> the whole dataset x times(for each processor 1 time).
>
>
> I found the wiki for a structured grid parallel reader (
> http://www.paraview.org/Wiki/Writing_ParaView_Readers) and used it as
> orientation.
>
>
> My RequestInformation looks like this:
>
>
> //Reading basic information
>
> //Reading in the extent from the file
>
> int extent[6];
>
> //storing the extent in the array
>
> vtkInformation* outInfo=outputVector->GetInformationObject(0);
>
> outInfo->Set(CAN_HANDLE_PIECE_REQUEST(),1);
>
> outInfo ->Set(vtkStreamingDemandDrivenPipeline::WHOLE_EXTENT(),extent,6);
>
>
>
> RequestData looks like this:
>
>
> vtkProcessModule *ParInfo;
> vtkInformation *outInfo = outputVector->GetInformationObject(0);
> vtkMultiBlockDataSet* multiBlock = vtkMultiBlockDataSet::
> SafeDownCast(outInfo->Get(vtkDataObject::DATA_OBJECT()));
>
> int subext[6];
> outInfo->Get(vtkStreamingDemandDrivenPipeline::UPDATE_EXTENT(),subext);
>
> cout<<"Num of Processors = "<<ParInfo->GetNumberOfLocalPartitions()<<endl;
>
> cout<< "subext from rank"<< ParInfo->GetPartitionId() << " "
> <<subext[0]<<.......<<.....<< ex[5] <<endl;
>
> //Reading the grid and the data-set
>
> Lets say the extent is 50x120x150 and i start the server with
> mpirun -np 2 pvs and connecting the client i get the following "output":
>
> Num of Processors = 2
> Num of Processors = 2
> subext from rank0 0 50 0 120 0 150
> subext from rank1 0 50 0 120 0 150
> But at the end the Dataset is still visualized correctly.
>
>
> Normally "outInfo->Get(vtkStreamingDemandDrivenPipeline::UPDATE_EXTENT(),subext);"
> should produce the sub-extent for the rank or am i wrong?
>
> What am I doing wrong, or what do I have to do to get the sub-extent?
>
>
> Thank you very much in advance,
> Markus Moser
>
>
> Markus Moser
> Student assistant
>
> Chair of Fluid Mechanics and Institute of Aerodynamics
>
> Wüllnerstraße 5a
> RWTH Aachen University
>
> 52062 Aachen
> Germany
>
>
>
>
>
>
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