[vtkusers] problem in writing data with vtkXMLMultiBlockDataWriter ...

[Utkarsh Ayachit]

Use vtkXMLPMultiBlockDataWriter
(http://www.vtk.org/doc/nightly/html/classvtkXMLPMultiBlockDataWriter.html)
instead. For it to work correctly, you'll need to setup a global
vtkMPIController. Since you're calling MPI_Init() youself, you can do
something like following after MPI_Init().

vtkNew<vtkMPIController> controller;
controller->Initialize(argv, argc, /*initializedExternally*/ true);
vtkMultiProcessController::SetGlobalController(controller.Get());

On Wed, May 31, 2017 at 10:00 AM, Ufuk Turuncoglu
<ufuk.turuncoglu at itu.edu.tr> wrote:
> Hi,
>
> I am trying to create very simple example of creating vtkMultiBlockDataSet
> using vtkStructuredGrid to sole a problem of mine in ParaView Catalyst. By
> this way, i could test some ideas without overhead of simulation code. In
> this case, i wrote following C++ code to demonstrate it. The problem is that
> the result test.vtm file includes information only one piece of data,
>
> <?xml version="1.0"?>
> <VTKFile type="vtkMultiBlockDataSet" version="1.0" byte_order="LittleEndian"
> header_type="UInt32" compressor="vtkZLibDataCompressor">
>   <vtkMultiBlockDataSet>
>     <Piece index="0">
>       <DataSet index="1" file="test/test_1.vts">
>       </DataSet>
>     </Piece>
>   </vtkMultiBlockDataSet>
> </VTKFile>
>
> but if i run the code with 4 core the test/ directory contains four file. I
> also observed that the file name written to test.vtm is changing based on
> the fastest core. So, i just wonder that am i missing something in here.
>
> Thanks,
> Regards,
>
> --ufuk
>
> #include <iostream>
> #include "mpi.h"
> #include "vtkStructuredGrid.h"
> #include "vtkSmartPointer.h"
> #include "vtkMultiBlockDataSet.h"
> #include "vtkMultiPieceDataSet.h"
> #include "vtkNew.h"
> #include "vtkXMLMultiBlockDataWriter.h"
>
> using namespace std;
>
> // global variables
> int const N = 10;
> int const tileX = 2;
> int const tileY = 2;
>
> int main(int argc, char** argv) {
>   // initialize MPI
>   MPI_Init(NULL, NULL);
>
>   // get number of processor and rank
>   int nproc, myid;
>   MPI_Comm_size(MPI_COMM_WORLD, &nproc);
>   MPI_Comm_rank(MPI_COMM_WORLD, &myid);
>
>   // create 2d decomposition parameters
>   bool hasLeft = false, hasTop = false;
>   if (myid%tileX == 0) hasLeft = true;
>   if (myid/tileY == 0) hasTop = true;
>   //cout << myid << " of " << nproc << " " << boolalpha << hasLeft << " " <<
> hasTop << endl;
>
>   // create structured grid
>   vtkSmartPointer<vtkStructuredGrid> grid =
> vtkSmartPointer<vtkStructuredGrid>::New();
>
>   // define grid coordinates
>   vtkSmartPointer<vtkPoints> points = vtkSmartPointer<vtkPoints>::New();
>   points->SetNumberOfPoints(N/tileX*N/tileY);
>
>   int istr = myid%tileX*N/tileX;
>   int iend = istr+N/tileX-1;
>   int jstr = myid/tileX*N/tileY;
>   int jend = jstr+N/tileY-1;
>   //cout << myid << " " << istr << " " << iend << " " << jstr << " " << jend
> << endl;
>
>   int id = 0;
>   for (int i = istr; i < iend; i++) {
>     for (int j = jstr; j < jend; j++) {
>       points->SetPoint(id, i, j, 0);
>       id = id+1;
>     }
>   }
>
>   grid->SetPoints(points);
>   grid->SetExtent(istr, iend, jstr, jend, 0, 0);
>   points->Delete();
>
>   // create multi block grid
>   vtkMultiBlockDataSet* mb = vtkMultiBlockDataSet::New();
>   vtkNew<vtkMultiPieceDataSet> mpds;
>   mpds->SetNumberOfPieces(nproc);
>   mpds->SetPiece(myid, grid.GetPointer());
>   mb->SetNumberOfBlocks(1);
>   mb->SetBlock(0, mpds.GetPointer());
>
>   // create a writer
>   vtkSmartPointer<vtkXMLMultiBlockDataWriter> mbw =
> vtkSmartPointer<vtkXMLMultiBlockDataWriter>::New();
>   mbw->SetFileName("test.vtm");
>   mbw->SetDataModeToAscii();
>   mbw->SetInputData(mb);
>   mbw->Write();
>
>   // finalize the MPI environment.
>   MPI_Finalize();
>
>   return 0;
> }
>
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