Method MergeRemoteModels

Filters/ParallelStatistics/vtkGenerateStatistics.cxx:1610–1745

}

int vtkGenerateStatistics::MergeRemoteModels(vtkPartitionedDataSetCollection* modelTree)
{
  auto* controller = this->Controller;
#if VTK_DBG_MODELDATA
  reportRanks("*** Before Merge ***", modelTree, controller);
#endif
  if (!controller)
  {
    controller = vtkMultiProcessController::GetGlobalController();
  }
  if (!controller)
  {
    // No work to do.
    return 0;
  }
  int rank = controller->GetLocalProcessId();
  int numberOfRanks = controller->GetNumberOfProcesses();
  if (numberOfRanks < 2)
  {
    // No work to do.
    return 0;
  }
  int maxPower = std::log2(vtkMath::NearestPowerOfTwo(numberOfRanks));
#if VTK_DBG_MODELDATA
  // For debugging:
  std::ostringstream commlog;
  commlog << "/tmp/comm_" << rank << ".log";
#endif
  // Create a writer to serialize **LOCAL** model information ONLY.
  // We send the resulting XML via \a controller to a partner rank per pass,
  // where it will be aggregated with the partner's model (if any).
  vtkNew<vtkGenericDataObjectWriter> serializer;
  serializer->SetInputDataObject(0, modelTree);
  serializer->WriteToOutputStringOn();
  serializer->Write();
  std::string localModelString = serializer->GetOutputString();
  std::size_t localModelSize = localModelString.size();
  vtkNew<vtkGenericDataObjectReader> deserializer;
  deserializer->ReadFromInputStringOn();
  {
#if VTK_DBG_MODELDATA
    std::ofstream log(commlog.str().c_str());
    log << "max power " << maxPower << "\n";
#endif
    for (int power = 0; power < maxPower; ++power)
    {
#if VTK_DBG_MODELDATA
      log << "Pass " << power << "\n";
#endif
      int delta = (1 << power);
      if (rank % delta == 0)
      {
        bool recvUp = (rank % (2 * delta) == 0);
        if (recvUp)
        {
          int recvFrom = (rank + delta >= numberOfRanks ? -1 : rank + delta);
          if (recvFrom < 0)
          {