Return the GN (growing network) digraph with n nodes.
The 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 degree.
The graph is always a (directed) tree.
Example:
>>> D=nx.gn_graph(10) # the GN graph
>>> G=D.to_undirected() # the undirected version
To specify an attachment kernel use the kernel keyword
>>> D=nx.gn_graph(10,kernel=lambda x:x**1.5) # A_k=k^1.5
Reference:
@article{krapivsky-2001-organization,
title = {Organization of Growing Random Networks},
author = {P. L. Krapivsky and S. Redner},
journal = {Phys. Rev. E},
volume = {63},
pages = {066123},
year = {2001},
}