Use this if you are using igraph from R
| hrg_tree {igraph} | R Documentation | 
hrg_tree creates the corresponsing igraph tree of a hierarchical
random graph model.
hrg_tree(hrg)
| hrg | A hierarchical random graph model. | 
An igraph graph.
Other hierarchical random graph functions: 
consensus_tree(),
fit_hrg(),
hrg-methods,
hrg(),
predict_edges(),
print.igraphHRGConsensus(),
print.igraphHRG(),
sample_hrg()