Method Gather

Rendering/ParallelLIC/vtkParallelTimer.cxx:287–338

------------------------------------------------------------------------------

//------------------------------------------------------------------------------
void vtkParallelTimerBuffer::Gather(int rootRank)
{
  int mpiOk;
  MPI_Initialized(&mpiOk);
  if (!mpiOk)
  {
    return;
  }
  int worldRank;
  MPI_Comm_rank(MPI_COMM_WORLD, &worldRank);
  int worldSize;
  MPI_Comm_size(MPI_COMM_WORLD, &worldSize);

  // in serial this is a no-op
  if (worldSize > 1)
  {
    int* bufferSizes = nullptr;
    int* disp = nullptr;
    if (worldRank == rootRank)
    {
      bufferSizes = static_cast<int*>(malloc(worldSize * sizeof(int)));
      disp = static_cast<int*>(malloc(worldSize * sizeof(int)));
    }
    int bufferSize = static_cast<int>(this->GetSize());
    MPI_Gather(&bufferSize, 1, MPI_INT, bufferSizes, 1, MPI_INT, rootRank, MPI_COMM_WORLD);
    char* log = nullptr;
    int cumSize = 0;
    if (worldRank == rootRank)
    {
      for (int i = 0; i < worldSize; ++i)
      {
        disp[i] = cumSize;
        cumSize += bufferSizes[i];
      }
      log = static_cast<char*>(malloc(cumSize));
    }
    MPI_Gatherv(
      this->Data, bufferSize, MPI_CHAR, log, bufferSizes, disp, MPI_CHAR, rootRank, MPI_COMM_WORLD);
    if (worldRank == rootRank)
    {
      this->Clear();
      this->PushBack(log, cumSize);
      free(bufferSizes);
      free(disp);
      free(log);
    }
    else
    {
      this->Clear();
    }
  }
}

//------------------------------------------------------------------------------
void vtkParallelTimerBuffer::PushBack(const void* data, size_t n)