Method ComputeTopoHash

tensorflow/core/grappler/graph_analyzer/sig_node.cc:104–153

}

void SigNode::ComputeTopoHash(int distance) {
  // The new starting point.
  next_hashed_nodes_ = last_hashed_nodes_;
  if (debug) {
    LOG(INFO) << "DEBUG    node " << name() << " mask=" << std::hex
              << next_hashed_nodes_;
  }

  if (hash_is_final_) {
    return;
  }

  CHECK(topo_hash_.size() == distance);

  int prev = distance - 1;

  // Start with own's local topology hash. This value is stable, so
  // if the hashes of the surrounding nodes don't change on the following
  // distances, the hash of this node won't change either.
  size_t hval = topo_hash_[0];

  if (!hashed_peers_.empty()) {
    size_t last_link_hash = hashed_peers_[0].link_hash;
    size_t comm_hash = 0;

    for (const auto& entry : hashed_peers_) {
      if (entry.link_hash != last_link_hash) {
        CombineHash(last_link_hash, &hval);
        CombineHash(comm_hash, &hval);
        comm_hash = 0;
        last_link_hash = entry.link_hash;
      }

      // The links in the same vector are commutative, so combine their
      // hashes in a commutative way.
      CombineHashCommutative(entry.peer->GetTopoHash(prev), &comm_hash);
      next_hashed_nodes_ |= entry.peer->last_hashed_nodes_;
      if (debug) {
        LOG(INFO) << "DEBUG    node " << name() << " += " << entry.peer->name()
                  << " mask=" << std::hex << next_hashed_nodes_;
      }
    }

    // The last commutative group.
    CombineHash(last_link_hash, &hval);
    CombineHash(comm_hash, &hval);
  }

  topo_hash_.push_back(hval);
}

size_t SigNode::GetTopoHash(int distance) const {
  CHECK(!topo_hash_.empty());