Graph graph(OpRegistry::Global());
  GraphConstructorOptions graph_opts;
  graph_opts.expect_device_spec = true;
  graph_opts.allow_internal_ops = true;
  TF_RETURN_IF_ERROR(
      ConvertGraphDefToGraph(graph_opts, auto_clustered_graph_def, &graph));

  // cluster_id -> (operation name -> # of operations)
  const int kNoCluster = -1;
  std::map<int, std::map<string, int>> clusters;
  std::map<int, int> cluster_size;