REINVENT , BAR and Hill-Climb , as well as in combination with KL regularization for non-regularized strategies (Experiment 4, Figure ). In the interest of standardisation, the prior was trained on the GuacaMol train dataset. The RL strategies were applied to six tasks of varying difficulty (see Methods). DF2 was used in all cases except for the Risperidone similarity task which uses a lower minimum score threshold due (DF3) to low similarity values.