tf内部图描述graph

// Thread compatible but not thread safe.class Graph { public:  explicit Graph(const OpRegistryInterface* registry);  explicit Graph(const FunctionLibraryDefinition& flib_def);  ~Graph();  static const int kControlSlot;  const VersionDef& versions() const;  void set_versions(const VersionDef& versions);  Node* AddNode(const NodeDef& node_def, Status* status);  Node* CopyNode(Node* node);  void RemoveNode(Node* node);  const Edge* AddEdge(Node* source, int x, Node* dest, int y);  const Edge* AddControlEdge(Node* source, Node* dest) {    return AddEdge(source, kControlSlot, dest, kControlSlot);  }  void RemoveEdge(const Edge* edge);  Status AddFunctionLibrary(const FunctionDefLibrary& fdef_lib);  int num_nodes() const { return num_nodes_; }  int num_op_nodes() const {    DCHECK_GE(num_nodes_, 2);    return num_nodes_ - 2;  }

  int num_edges() const { return num_edges_; }  void ToGraphDefSubRange(GraphDef* graph_def, int from_node_id) const;  void ToGraphDef(GraphDef* graph_def) const;  string NewName(StringPiece prefix);

  gtl::iterator_range<NodeIter> nodes() const;  gtl::iterator_range<NodeIter> op_nodes() const;  int num_node_ids() const { return nodes_.size(); }  Node* FindNodeId(int id) const { return nodes_[id]; }

  int num_edge_ids() const { return edges_.size(); }  const Edge* FindEdgeId(int id) const { return edges_[id]; }  GraphEdgesIterable edges() const { return GraphEdgesIterable(edges_); }  enum { kSourceId = 0, kSinkId = 1 };  Node* source_node() const { return FindNodeId(kSourceId); }  Node* sink_node() const { return FindNodeId(kSinkId); }

  const OpRegistryInterface* op_registry() const { return &ops_; }  const FunctionLibraryDefinition& flib_def() const { return ops_; }

  void CheckDeviceNameIndex(int index) {    DCHECK_GE(index, 0);    DCHECK_LT(index, static_cast<int>(device_names_.size()));  }

  int InternDeviceName(const string& device_name);

  const string& get_assigned_device_name(const Node& node) const {    return device_names_[node.assigned_device_name_index()];  }

  void set_assigned_device_name_index(Node* node, int device_name_index) {    CheckDeviceNameIndex(device_name_index);    node->assigned_device_name_index_ = device_name_index;  }

  void set_assigned_device_name(Node* node, const string& device_name) {    node->assigned_device_name_index_ = InternDeviceName(device_name);  }

  Status IsValidNode(const Node* node) const;  Status IsValidOutputTensor(const Node* node, int idx) const;

 private:  Node* AllocateNode(std::shared_ptr<NodeProperties> props, const Node* cost_node);  void ReleaseNode(Node* node);  FunctionLibraryDefinition ops_;  const std::unique_ptr<VersionDef> versions_;  core::Arena arena_;  std::vector<Node*> nodes_;

  int64 num_nodes_ = 0;  std::vector<Edge*> edges_;  int num_edges_ = 0;  std::vector<Node*> free_nodes_;  std::vector<Edge*> free_edges_;

  int name_counter_ = 0;  std::vector<string> device_names_;  std::unordered_map<string, int> device_names_map_;  TF_DISALLOW_COPY_AND_ASSIGN(Graph);};