Function GenerateAllocations

Filters/Sources/vtkPartitionedDataSetSource.cxx:42–77

* Generate allocations for the given ranks taking in consideration that: * * - Some ranks might not accept any partitions * - Some ranks might accept a finite amount of partitions. * - Some ranks might accept a any multiplicity of partitions. * */

 *
 */
std::vector<int> GenerateAllocations(const std::vector<int>& allocs, const int numPartitions)
{
  std::vector<int> partsPerRank(allocs);

  const int partsAllocated = std::accumulate(allocs.begin(), allocs.end(), 0,
    [](int a, int b) { return (b == NUM_PARTITIONS::MULTIPLE_PARTITIONS) ? a : a + b; });

  const int partsToAlloc = std::max(numPartitions - partsAllocated, 0);

  if (partsToAlloc > 0)
  {
    // Make a vector with iters of partitions to be alloc
    std::vector<std::vector<int>::iterator> ranksToAllocIters;
    auto it = partsPerRank.begin();
    while (partsPerRank.end() !=
      (it = find(partsPerRank.begin(), partsPerRank.end(), NUM_PARTITIONS::MULTIPLE_PARTITIONS)))
    {
      *it = 0; // Initialize to 0
      ranksToAllocIters.push_back(it);
    }

    // Schedule blocks in a round-robin fashion
    const size_t ranksToAllocSize = ranksToAllocIters.size();
    for (size_t i = 0; i < static_cast<size_t>(partsToAlloc); ++i)
    {
      ++(*ranksToAllocIters[i % ranksToAllocSize]);
    }
  }

  if (std::accumulate(partsPerRank.begin(), partsPerRank.end(), 0) != numPartitions)
  {
    vtkLogF(ERROR, "GenerateAllocations generated partitions != given numPartitions");
  }

  return partsPerRank;
}

// returns [start, end].
std::pair<int, int> GetRange(const int rank, const std::vector<int>& parts)