float OEGetRingValue(const OEChem::OEMolBase &mol)

This is a function that assigns a value to a molecule or fragment based on the number and type of ring systems it contains. Ring systems that are favored by small-molecule medicinal chemistry receive higher scores. No preference is given between aromatic and aliphatic rings. Ring fusions are favored over spiro ring systems and common ring sizes (5,6) are favored over unusual ring sizes. This value is not recommended for filtering or cutoffs, yet can be useful for ordering compounds from a set of potential candidates.