Function GetReadyNodes

tensorflow/core/graph/graph_partition.cc:1679–1714

namespace {

void GetReadyNodes(std::unordered_set<Node*>& done,
                   const std::string& loc,
                   std::unordered_set<Node*>* node_set,
                   std::unordered_map<std::string, std::unordered_set<Node*> >* ready_nodes) {
  bool exit = false;
  while (!exit && node_set->size() > 0) {
    exit = true;
    for (auto n : *node_set) {
      if (!n->IsOp()) {
        LOG(FATAL) << "There should be no _Source or _Sink here.";
      }

      bool ready = true;
      for (const Edge* in_edge : n->in_edges()) {
        Node* src = in_edge->src();
        if (!src->IsOp()) continue;
        // NOTE(jiankeng.pt): skip NextIteration to make topological sort successful.
        if (n->IsMerge() && src->IsNextIteration()) {
          continue;
        }
        if (done.find(src) != done.end()) continue;
        // (*ready_nodes)[loc].find(src) != (*ready_nodes)[loc].end()
        ready = false;
        break;
      }
      if (ready) {
        exit = false;
        (*ready_nodes)[loc].insert(n);
      }
    }

    for (auto n : (*ready_nodes)[loc]) {
      node_set->erase(n);
    }
  }
}

} // namespace