bfs_layout#

bfs_layout(G, start, *, align='vertical', scale=1, center=None, store_pos_as=None)[source]#

Position nodes according to breadth-first search algorithm.

Parameters:

GNetworkX graph: A position will be assigned to every node in G.
startnode in G: Starting node for bfs
alignstring (default=’vertical’): The alignment of nodes within a layer, either "vertical" or "horizontal".
scalenumber (default: 1): Scale factor for positions.
centerarray-like or None: Coordinate pair around which to center the layout.
store_pos_asstr, default None: If non-None, the position of each node will be stored on the graph as an attribute with this string as its name, which can be accessed with G.nodes[...][store_pos_as]. The function still returns the dictionary.

Returns:

posdict: A dictionary of positions keyed by node.

Notes

This algorithm currently only works in two dimensions and does not try to minimize edge crossings.

Examples

>>> from pprint import pprint
>>> G = nx.path_graph(4)
>>> pos = nx.bfs_layout(G, 0)
>>> # suppress the returned dict and store on the graph directly
>>> _ = nx.bfs_layout(G, 0, store_pos_as="pos")
>>> pprint(nx.get_node_attributes(G, "pos"))
{0: array([-1.,  0.]),
 1: array([-0.33333333,  0.        ]),
 2: array([0.33333333, 0.        ]),
 3: array([1., 0.])}