Method Execute

Filters/FlowPaths/vtkParticlePathFilter.cxx:75–250

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//------------------------------------------------------------------------------
int vtkParticlePathFilter::Execute(
  vtkInformation* request, vtkInformationVector** inputVector, vtkInformationVector* outputVector)
{
  int retVal = this->Superclass::Execute(request, inputVector, outputVector);

  // First, for every particle that we receive, we need to ask the original rank for its Path data
  // so we can reconstruct the paths.
  if (this->Controller && this->Controller->GetNumberOfProcesses() > 1)
  {
    int myRank = this->Controller ? this->Controller->GetLocalProcessId() : 0;

    vtkIdType startId = this->Points->GetNumberOfPoints();
    vtkIdType endId = startId;

    // We map points using InjectedPointId
    vtkIdType nParticlesSentLocal = static_cast<vtkIdType>(this->MPIRecvList.size());
    std::vector<vtkIdType> particleRequests(nParticlesSentLocal);
    vtkIdType counter = 0;
    for (const auto& pair : this->MPIRecvList)
    {
      const auto& info = pair.second;
      particleRequests[counter++] = info.InjectedPointId;
    }

    std::vector<vtkIdType> allNumParticles(this->Controller->GetNumberOfProcesses());

    this->Controller->AllGather(&nParticlesSentLocal, allNumParticles.data(), 1);

    vtkIdType nParticlesSent = 0;
    std::vector<vtkIdType> offsets(this->Controller->GetNumberOfProcesses() + 1);
    offsets.front() = 0;

    for (std::size_t i = 0; i < allNumParticles.size(); ++i)
    {
      offsets[i + 1] = offsets[i] + allNumParticles[i];
      nParticlesSent += allNumParticles[i];
    }

    std::vector<vtkIdType> allParticleRequests(nParticlesSent);

    // We share with everyone the particles that we require. The processes owning the relevant Paths
    // data will know what we want and we can exchange data.
    this->Controller->AllGatherV(particleRequests.data(), allParticleRequests.data(),
      nParticlesSentLocal, allNumParticles.data(), offsets.data());

    std::vector<vtkNew<vtkIdList>> sendLists(this->Controller->GetNumberOfProcesses());
    counter = 0;
    int rank = 0;

    while (rank < this->Controller->GetNumberOfProcesses())
    {
      if (allParticleRequests.empty())
      {
        break;
      }
      if (rank == myRank)
      {
        // skipping ourselves