Method WriteImageMetaData

IO/Parallel/vtkPDataSetWriter.cxx:314–422

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//------------------------------------------------------------------------------
int vtkPDataSetWriter::WriteImageMetaData(
  vtkImageData* input, char* root, char* str, size_t strSize, ostream* fptr)
{
  int* pi;
  double* pf;
  vtkInformation* inInfo = this->GetInputInformation();

  // We should indicate the type of data that is being saved.
  *fptr << "      dataType=\"" << input->GetClassName() << "\"" << endl;
  // Image data has a buch of meta data.
  *fptr << "      scalarType=\"" << input->GetScalarType() << "\"" << endl;
  pf = inInfo->Get(vtkDataObject::ORIGIN());
  *fptr << "      origin=\"" << pf[0] << " " << pf[1] << " " << pf[2] << "\"" << endl;
  pf = inInfo->Get(vtkDataObject::SPACING());
  *fptr << "      spacing=\"" << pf[0] << " " << pf[1] << " " << pf[2] << "\"" << endl;
  pi = vtkStreamingDemandDrivenPipeline::GetWholeExtent(inInfo);
  *fptr << "      wholeExtent=\"" << pi[0] << " " << pi[1] << " " << pi[2] << " " << pi[3] << " "
        << pi[4] << " " << pi[5] << "\"" << endl;

  // This is making the assumption that all the files will be written out by
  // some processes.
  *fptr << "      numberOfPieces=\"" << this->NumberOfPieces << "\" >" << endl;

  // The code below gathers extens from all processes to write in the
  // meta-file. Note that the extent of each piece was already stored by
  // each writer. This is gathering it all to root node.
  if (this->Controller)
  {
    // Even though the logic is pretty straightforward, we need to
    // do a fair amount of work to use GatherV. Each rank simply
    // serializes its extents to 7 int blocks - piece number and 6
    // extent values. Then we gather this all to root.
    int rank = this->Controller->GetLocalProcessId();
    int nRanks = this->Controller->GetNumberOfProcesses();

    int nPiecesTotal = 0;
    vtkIdType nPieces = static_cast<vtkIdType>(this->Extents.size());

    std::vector<vtkIdType> offsets;
    std::vector<vtkIdType> nPiecesAll;
    std::vector<vtkIdType> recvLengths;
    if (rank == 0)
    {
      offsets.resize(nRanks);
      nPiecesAll.resize(nRanks);
      recvLengths.resize(nRanks);
    }
    this->Controller->Gather(&nPieces, nPiecesAll.data(), 1, 0);
    if (rank == 0)
    {
      for (int i = 0; i < nRanks; i++)
      {
        offsets[i] = nPiecesTotal * 7;
        nPiecesTotal += nPiecesAll[i];
        recvLengths[i] = nPiecesAll[i] * 7;
      }
    }
    std::vector<int> sendBuffer;