A third option which also has significant potential is to compare the International Chemical Identifier (InChI) for various molecules. An InChI is a string identifier for a molecule which is designed to be independent of resonance structures and would therefore give the same result as the loose isomorphism method, although multiplicity would still need to be considered separately because InChI does not account for electronic states. Additionally, string comparison is extremely fast. Unfortunately, InChI generation time is non-trivial.