Method Reduce

Filters/ParallelStatistics/vtkPContingencyStatistics.cxx:392–451

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//------------------------------------------------------------------------------
bool vtkPContingencyStatistics::Reduce(vtkIdType& xySizeTotal, char* xyPacked_g,
  vtkStdString& xyPacked_l, vtkIdType& kcSizeTotal, vtkIdType* kcValues_g,
  std::vector<vtkIdType>& kcValues_l)
{
  // First, unpack the packet of strings
  std::vector<vtkStdString> xyValues_g;
  StringBufferToStringVector(std::string(xyPacked_g, xySizeTotal), xyValues_g);

  // Second, check consistency: we must have the same number of xy and kc entries
  if (vtkIdType(xyValues_g.size()) != kcSizeTotal)
  {
    vtkErrorMacro("Reduction error on process "
      << this->Controller->GetCommunicator()->GetLocalProcessId()
      << ": inconsistent number of (x,y) and (k,c) pairs: " << xyValues_g.size() << " <> "
      << kcSizeTotal << ".");

    return true;
  }

  // Third, reduce to the global contingency table
  typedef std::map<std::string, vtkIdType> Distribution;
  typedef std::map<std::string, Distribution> Bidistribution;
  std::map<vtkIdType, Bidistribution> contingencyTable;
  vtkIdType i = 0;
  for (std::vector<vtkStdString>::iterator vit = xyValues_g.begin(); vit != xyValues_g.end();
       vit += 2, i += 2)
  {
    contingencyTable[kcValues_g[i]][*vit][*(vit + 1)] += kcValues_g[i + 1];
  }

  // Fourth, prepare send buffers of (global) xy and kc values
  std::vector<std::string> xyValues_l;
  kcValues_l.clear();
  for (std::map<vtkIdType, Bidistribution>::iterator ait = contingencyTable.begin();
       ait != contingencyTable.end(); ++ait)
  {
    Bidistribution bidi = ait->second;
    for (Bidistribution::iterator bit = bidi.begin(); bit != bidi.end(); ++bit)
    {
      Distribution di = bit->second;
      for (Distribution::iterator dit = di.begin(); dit != di.end(); ++dit)
      {
        // Push back x and y to list of strings
        xyValues_l.push_back(bit->first); // x
        xyValues_l.push_back(dit->first); // y

        // Push back (X,Y) index and #(x,y) to list of strings
        kcValues_l.push_back(ait->first);  // k
        kcValues_l.push_back(dit->second); // c
      }
    }
  }
  StringVectorToStringBuffer(xyValues_l, xyPacked_l);

  // Last, update xy and kc buffer sizes (which have changed because of the reduction)
  xySizeTotal = static_cast<vtkIdType>(xyPacked_l.size());
  kcSizeTotal = static_cast<vtkIdType>(kcValues_l.size());