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# gn_graph¶

gn_graph(n, kernel=None, create_using=None, seed=None)[source]

Return the growing network (GN) digraph with n nodes.

The GN graph is built by adding nodes one at a time with a link to one previously added node. The target node for the link is chosen with probability based on degree. The default attachment kernel is a linear function of the degree of a node.

The graph is always a (directed) tree.

Parameters: n (int) – The number of nodes for the generated graph. kernel (function) – The attachment kernel. create_using (graph, optional (default DiGraph)) – Return graph of this type. The instance will be cleared. seed (hashable object, optional) – The seed for the random number generator.

Examples

To create the undirected GN graph, use the to_directed() method:

>>> D = nx.gn_graph(10)  # the GN graph
>>> G = D.to_undirected()  # the undirected version


To specify an attachment kernel, use the kernel keyword argument:

>>> D = nx.gn_graph(10, kernel=lambda x: x ** 1.5)  # A_k = k^1.5


References

 [1] P. L. Krapivsky and S. Redner, Organization of Growing Random Networks, Phys. Rev. E, 63, 066123, 2001.