The ability to accurate encode and decode DeepSMILES from SMILES was tested during development by roundtripping SMILES through DeepSMILES, checking that the canonical SMILES of the original and roundtripped SMILES was identical. The roundtrip test was carried out three times; once transforming both parentheses and ring closures, and then testing each on its own. The datasets used were canonical SMILES (including stereochemistry) generated by the CDK , OEChem ,