Method RequestInformation

IO/ParallelNetCDF/vtkPNetCDFPOPReader.cxx:152–270

------------------------------------------------------------------------------ RequestInformation supplies global meta information This should return the reality of what the reader is going to supply. This retrieve the extents for the rectilinear grid NC_MAX_VAR_DIMS comes from the nc library

// This retrieve the extents for the rectilinear grid
// NC_MAX_VAR_DIMS comes from the nc library
int vtkPNetCDFPOPReader::RequestInformation(vtkInformation* vtkNotUsed(request),
  vtkInformationVector** vtkNotUsed(inputVector), vtkInformationVector* outputVector)
{
  vtkInformation* outInfo = outputVector->GetInformationObject(0);
  if (this->FileName == nullptr)
  {
    vtkErrorMacro("FileName not set.");
    return 0;
  }

  // every rank that is a reader process needs to open the file
  if (this->IsReaderRank())
  {

    if (this->OpenedFileName)
    {
      nc_close(this->NCDFFD);
    }
    int retval = nc_open(this->FileName, NC_NOWRITE, &this->NCDFFD); // read file
    if (retval != NC_NOERR)                                          // checks if read file error
    {
      vtkErrorMacro(<< "Can't read file " << nc_strerror(retval));
      this->SetOpenedFileName(nullptr);
      return 0;
    }
    this->SetOpenedFileName(this->FileName);
  }
  // first reader reads the metadata and broadcasts it to everyone else
  int extent[6];
  char variableName[NC_MAX_NAME + 1];
  if (this->IsFirstReaderRank())
  {
    // get number of variables from file
    int numberOfVariables;
    nc_inq_nvars(this->NCDFFD, &numberOfVariables);
    int dimidsp[NC_MAX_VAR_DIMS];
    int dataDimension;
    size_t dimensions[4]; // dimension value
    this->Internals->VariableMap.resize(numberOfVariables);
    int actualVariableCounter = 0;
    // For every variable in the file
    for (int i = 0; i < numberOfVariables; i++)
    {
      this->Internals->VariableMap[i] = -1;
      // get number of dimensions
      CALL_NETCDF_INT(nc_inq_varndims(this->NCDFFD, i, &dataDimension));
      // Variable Dimension ID's containing x,y,z coords for the rectilinear
      // grid spacing
      CALL_NETCDF_INT(nc_inq_vardimid(this->NCDFFD, i, dimidsp));
      if (dataDimension == 3)
      {
        this->Internals->VariableMap[i] = actualVariableCounter++;
        // get variable name
        CALL_NETCDF_INT(nc_inq_varname(this->NCDFFD, i, variableName));
        this->Internals->VariableArraySelection->AddArray(variableName);
        for (int m = 0; m < dataDimension; m++)
        {
          CALL_NETCDF_INT(nc_inq_dimlen(this->NCDFFD, dimidsp[m], dimensions + m));