.. SPDX-FileCopyrightText: 2019-2020 Intel Corporation .. .. SPDX-License-Identifier: CC-BY-4.0 ========== Flow Graph ========== **[flow_graph]** In addition to loop parallelism, the oneAPI Threading Building Blocks (oneTBB) library also supports graph parallelism. With this feature, highly scalable and completely sequential graphs can be created. There are three types of components used to implement a graph: * A ``graph`` class instance * Nodes * Ports and edges Graph Class ----------- The ``graph`` class instance owns all the tasks created on behalf of the flow graph. Users can wait on the ``graph`` if they need to wait for the completion of all of the tasks related to the flow graph execution. Users can also register external interactions with the ``graph`` and run tasks under the ownership of the flow graph. .. toctree:: :titlesonly: flow_graph/graph_cls.rst Nodes ----- Abstract Interfaces ~~~~~~~~~~~~~~~~~~~ To be used as a graph node type, a class needs to inherit certain abstract types and implement the corresponding interfaces. ``graph_node`` is the base class for any other node type; its interfaces always have to be implemented. If a node sends messages to other nodes, it has to implement the ``sender`` interface, while with the ``receiver`` interface the node may accept messages. For nodes that have multiple inputs and/or outputs, each input port is a ``receiver`` and each output port is a ``sender``. .. toctree:: :titlesonly: flow_graph/graph_node_cls.rst flow_graph/sender.rst flow_graph/receiver.rst Properties ~~~~~~~~~~ Every node in a flow graph has its own properties. .. toctree:: :titlesonly: flow_graph/forwarding_and_buffering.rst Functional Nodes ~~~~~~~~~~~~~~~~ Functional nodes do computations in response to input messages (if any), and send the result or a signal to their successors. .. toctree:: :titlesonly: flow_graph/continue_node_cls.rst flow_graph/func_node_cls.rst flow_graph/input_node_cls.rst flow_graph/multifunc_node_cls.rst flow_graph/async_node_cls.rst **Auxiliary** .. toctree:: :titlesonly: flow_graph/functional_node_policies.rst flow_graph/node_priorities.rst flow_graph/predefined_concurrency_limits.rst flow_graph/copy_body_func.rst Buffering Nodes ~~~~~~~~~~~~~~~ Buffering nodes are designed to accumulate input messages and pass them to successors in a predefined order, depending on the node type. .. toctree:: :titlesonly: flow_graph/overwrite_node_cls.rst flow_graph/write_once_node_cls.rst flow_graph/buffer_node_cls.rst flow_graph/queue_node_cls.rst flow_graph/priority_queue_node_cls.rst flow_graph/sequencer_node_cls.rst Service Nodes ~~~~~~~~~~~~~ These nodes are designed for advanced control of the message flow, such as combining messages from different paths in a graph or limiting the number of simultaneously processed messages, as well as for creating reusable custom nodes. .. toctree:: :titlesonly: flow_graph/limiter_node_cls.rst flow_graph/broadcast_node_cls.rst flow_graph/join_node_cls.rst flow_graph/split_node_cls.rst flow_graph/indexer_node_cls.rst flow_graph/composite_node_cls.rst Ports and Edges --------------- Flow Graph provides an API to manage connections between the nodes. For nodes that have more than one input or output ports (for example, ``join_node``), making a connection requires to specify a certain port by using special helper functions. .. toctree:: :titlesonly: flow_graph/input_port_func.rst flow_graph/output_port_func.rst flow_graph/make_edge_func.rst flow_graph/remove_edge_func.rst Special Messages Types ---------------------- Flow Graph supports a set of specific message types. .. toctree:: :titlesonly: flow_graph/continue_msg_cls.rst flow_graph/tagged_msg_cls.rst Examples -------- .. toctree:: :titlesonly: flow_graph/dependency_flow_graph_example.rst flow_graph/message_flow_graph_example.rst