xref: /oneTBB/doc/main/reference/make_edges_function.rst (revision 67c11716)

.. _make_edges:

``make_edges`` function template
================================

.. note::
   To enable this feature, define the ``TBB_PREVIEW_FLOW_GRAPH_FEATURES`` macro to 1.

.. contents::
    :local:
    :depth: 1

Description
***********

The ``make_edges`` function template creates edges between a single node
and each node in a set of nodes.

There are two ways to connect nodes in a set and a single node using
``make_edges``:

.. figure:: ./Resources/make_edges_usage.png
   :align: center

API
***

Header
------

.. code:: cpp

    #include <oneapi/tbb/flow_graph.h>

Syntax
------

.. code:: cpp

    // node_set is an exposition-only name for the type returned from make_node_set function

    template <typename NodeType, typename Node, typename... Nodes>
    void make_edges(node_set<Node, Nodes...>& set, NodeType& node);

    template <typename NodeType, typename Node, typename... Nodes>
    void make_edges(NodeType& node, node_set<Node, Nodes...>& set);

Example
-------

The example implements the graph structure in the picture below.

.. figure:: ./Resources/make_edges_example.png
    :align: center

.. code:: cpp

    #define TBB_PREVIEW_FLOW_GRAPH_FEATURES 1
    #include <oneapi/tbb/flow_graph.h>

    int main() {
        using namespace oneapi::tbb::flow;

        graph g;
        broadcast_node<int> input(g);

        function_node doubler(g, unlimited, [](const int& i) { return 2 * i; });
        function_node squarer(g, unlimited, [](const int& i) { return i * i; });
        function_node cuber(g, unlimited, [](const int& i) { return i * i * i; });

        buffer_node<int> buffer(g);

        auto handlers = make_node_set(doubler, squarer, cuber);
        make_edges(input, handlers);
        make_edges(handlers, buffer);

        for (int i = 1; i <= 10; ++i) {
            input.try_put(i);
        }
        g.wait_for_all();
    }