Closed
Description
Issue previously open at #1518 for LightGraphs.jl.
The is_cyclic
function in LightGraphs.jl works well for directed graphs but for undirected graphs returns true
for any nonempty graph. The usual definition for undirected graphs is that cycles don't contain repeated links, so 1->2->1 is not considered a cycle (absent multiple edges.)
Useful for me because I want a function that will test whether an (undirected) network is a tree and easiest way to check that is to confirm the graph is acyclic+connected