Writing pvtu files from Catalyst ...

Development
1

Dear All,
I am having difficulties with writing out pvtu files from a Catalyst process. Writing them out directly using for instance a threshold defined within the python script works great, but I do have another function for processing the data directly. I can access all fields and perform the computation and in the end would like to write out the results as a vtkIntArray. Using one thread and vtkXMLUnstructuredGridWriter this works great, but in parallel from within Catalyst and using vtkXMLPUnstructuredGridWriter it writes out data to disk, the *.pvtu file also looks correct, but when reading the data back with ParaView, the XML reader complains about wrong formed tokens etc. Here is the part of C++ code I use to write out the files. The input data is a unstructured grid with one vtkUnsignedIntArray.:

vtkMultiProcessController* ctrl = vtkMultiProcessController::GetGlobalController();

vtkNew completeArrays;
completeArrays->SetController(ctrl);
completeArrays->SetInputData(isccpData);

vtkNew writer;
writer->SetInputConnection(completeArrays->GetOutputPort());
writer->SetNumberOfPieces(ctrl->GetNumberOfProcesses());
writer->SetStartPiece(0);
writer->SetEndPiece(ctrl->GetNumberOfProcesses()-1);
//writer->SetController(ctrl);
writer->SetUseSubdirectory(true);
writer->SetFileName(outputFile.c_str());
writer->Update();

I also looked into the Catalyst example and the test for vtkXMLPUnstructuredGridWriter. I also tried without using vtkCompleteArrays, but as it very well may be that process 0 does not have any points, I thought this will be on the safe side.

Thanks for any hints and Cheers,
Niklas

2

Hi Niklas,

Have you looked at using the vtkCPXMLPWriterPipeline? That along with maybe the CxxVTKPipelineExample under the Examples/Catalyst subdirectory of the source code may get you where you want to go, which I assume is using Catalyst without Python.

Good luck!
Andy

ps. I think the mistake you’re making with the vtkXMLPUnstructuredGridWriter is that it should be:

writer->SetStartPiece(ctrl->GetLocalProcessId());
writer->SetEndPiece(ctrl->GetLocalProcessId());

Also, I don’t think vtkCompleteArrays should be necessary here anymore, i.e. with ParaView 5.6.

1 Like
3

Thank you Andy, you are awesome!!!