This is an implementation of Smallest Set of Smallest Rings (SSSR) finding algorithm based on Perl Graph library.
Thus it should work with any Graph::Undirected object.
The code is largely taken from the cod-tools package.
The algorithm returns a superset of minimum cycle basis of a graph in order to produce deterministic results.
As a result it does not succumb to the counterexample of oxabicyclo[2.2.2]octane (section "SSSR and Uniqueness").
The algorithm has means to control the maximum size of rings included in the SSSR to reduce its complexity.
The default value of undef stands for no limit.