Method Learn

Filters/ParallelStatistics/vtkPOrderStatistics.cxx:115–344

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//------------------------------------------------------------------------------
void vtkPOrderStatistics::Learn(
  vtkTable* inData, vtkTable* inParameters, vtkStatisticalModel* outMeta)
{
  if (!outMeta)
  {
    return;
  }

  // First calculate order statistics on local data set
  this->Superclass::Learn(inData, inParameters, outMeta);

  if (!outMeta || outMeta->GetNumberOfTables(vtkStatisticalModel::Learned) < 1)
  {
    // No statistics were calculated.
    return;
  }

  // Make sure that parallel updates are needed, otherwise leave it at that.
  int np = this->Controller->GetNumberOfProcesses();
  if (np < 2)
  {
    return;
  }

  // Get ready for parallel calculations
  vtkCommunicator* com = this->Controller->GetCommunicator();
  if (!com)
  {
    vtkErrorMacro("No parallel communicator.");
  }

  // Figure local process id
  vtkIdType myRank = com->GetLocalProcessId();

  // NB: Use process 0 as sole reducer for now
  vtkIdType rProc = 0;

  // Iterate over primary tables
  int nParts = outMeta->GetNumberOfTables(vtkStatisticalModel::Learned);
  for (int b = 0; b < nParts; ++b)
  {
    // Fetch histogram table
    vtkTable* histoTab = outMeta->GetTable(vtkStatisticalModel::Learned, b);
    if (!histoTab)
    {
      continue;
    }
    std::string histoTabName = outMeta->GetTableName(vtkStatisticalModel::Learned, b);

    // Downcast columns to typed arrays for efficient data access
    vtkAbstractArray* vals = histoTab->GetColumnByName("Value");
    vtkIdTypeArray* card =
      vtkArrayDownCast<vtkIdTypeArray>(histoTab->GetColumnByName("Cardinality"));
    if (!vals || !card)
    {
      vtkErrorMacro("Column fetching error on process " << myRank << ".");

      return;