is_forest¶

is_forest(G)[source]¶

Returns True if G is a forest.

A forest is a graph with no undirected cycles.

For directed graphs, G is a forest if the underlying graph is a forest. The underlying graph is obtained by treating each directed edge as a single undirected edge in a multigraph.

Parameters:	G (graph) – The graph to test.
Returns:	b – A boolean that is `True` if `G` is a forest.
Return type:	bool

Notes

In another convention, a directed forest is known as a polyforest and then forest corresponds to a branching.