densest_subgraph-1b068f69f80facd4.yaml

---
features:
  - |
    Added a new function, :func:`~.densest_subgraph_of_size`, which is used to return a
    subgraph of given size that has the highest degree of connecitivity between the nodes.
    For example, if you wanted to find the subgraph of 5 nodes in a 19 node heavy hexagon
    graph:

    .. jupyter-execute::

        import retworkx
        from retworkx.visualization import mpl_draw

        graph = retworkx.generators.hexagonal_lattice_graph(4, 5)

        subgraph, node_map = retworkx.densest_subgraph_of_size(graph, 5)
        subgraph_edge_set = set(subgraph.edge_list())
        node_colors = []
        for node in graph.node_indices():
            if node in node_map:
              node_colors.append('red')
            else:
              node_colors.append('blue')
            graph[node] = node
        edge_colors = []
        for edge in graph.edge_list():
            if edge[0] in node_map and edge[1] in node_map:
                edge_colors.append('red')
            else:
                edge_colors.append('blue')
        mpl_draw(graph, with_labels=True, node_color=node_colors, edge_color=edge_colors, labels=str)