Method RedistributePTD

Filters/ParallelDIY2/vtkRedistributeDataSetFilter.cxx:680–863

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//------------------------------------------------------------------------------
bool vtkRedistributeDataSetFilter::RedistributePTD(vtkPartitionedDataSet* inputPDS,
  vtkPartitionedDataSet* outputPDS,
  const std::vector<vtkPartitioningStrategy::PartitionInformation>& info, unsigned int* ptdOffset,
  vtkIdType* mb_offset)
{
  if (!inputPDS || !outputPDS)
  {
    vtkErrorMacro("Either input or output PartitionedDataSet is nullptr");
    return false;
  }

  // assign global cell ids to inputDO, if not present.
  // we do this assignment before distributing cells if boundary mode is not
  // set to SPLIT_BOUNDARY_CELLS in which case we do after the split.
  vtkSmartPointer<vtkPartitionedDataSet> xfmedInput;
  if (this->GenerateGlobalCellIds && this->BoundaryMode != SPLIT_BOUNDARY_CELLS)
  {
    xfmedInput = this->AssignGlobalCellIds(inputPDS, mb_offset);
  }
  else
  {
    xfmedInput = inputPDS;
  }

  // We are distributing a vtkPartitionedDataSet. Our strategy is simple:
  // we split and distribute each input partition individually.
  // We then merge corresponding parts together to form the output partitioned
  // dataset.
  std::vector<vtkDataSet*> input_partitions;
  for (unsigned int cc = 0; cc < xfmedInput->GetNumberOfPartitions(); ++cc)
  {
    auto ds = xfmedInput->GetPartition(cc);
    if (ds && (ds->GetNumberOfPoints() > 0 || ds->GetNumberOfCells() > 0))
    {
      input_partitions.emplace_back(ds);
    }
    else
    {
      input_partitions.emplace_back(nullptr);
    }
  }

  auto controller = this->GetController();
  if (controller && controller->GetNumberOfProcesses() > 1)
  {
    unsigned int mysize = static_cast<unsigned int>(input_partitions.size());
    unsigned int allsize = 0;
    controller->AllReduce(&mysize, &allsize, 1, vtkCommunicator::MAX_OP);
    assert(allsize >= mysize);
    input_partitions.resize(allsize, nullptr);
  }

  if (input_partitions.empty())
  {
    // all ranks have empty data.
    return true;
  }