number_of_walks#
- number_of_walks(G, walk_length)[source]#
Returns the number of walks connecting each pair of nodes in
G
A walk is a sequence of nodes in which each adjacent pair of nodes in the sequence is adjacent in the graph. A walk can repeat the same edge and go in the opposite direction just as people can walk on a set of paths, but standing still is not counted as part of the walk.
This function only counts the walks with
walk_length
edges. Note that the number of nodes in the walk sequence is one more thanwalk_length
. The number of walks can grow very quickly on a larger graph and with a larger walk length.- Parameters:
- GNetworkX graph
- walk_lengthint
A nonnegative integer representing the length of a walk.
- Returns:
- dict
A dictionary of dictionaries in which outer keys are source nodes, inner keys are target nodes, and inner values are the number of walks of length
walk_length
connecting those nodes.
- Raises:
- ValueError
If
walk_length
is negative
Examples
>>> G = nx.Graph([(0, 1), (1, 2)]) >>> walks = nx.number_of_walks(G, 2) >>> walks {0: {0: 1, 1: 0, 2: 1}, 1: {0: 0, 1: 2, 2: 0}, 2: {0: 1, 1: 0, 2: 1}} >>> total_walks = sum(sum(tgts.values()) for _, tgts in walks.items())
You can also get the number of walks from a specific source node using the returned dictionary. For example, number of walks of length 1 from node 0 can be found as follows:
>>> walks = nx.number_of_walks(G, 1) >>> walks[0] {0: 0, 1: 1, 2: 0} >>> sum(walks[0].values()) # walks from 0 of length 1 1
Similarly, a target node can also be specified:
>>> walks[0][1] 1