that represents the agreement between the pre-trained RNN log-likelihood log p ψ 0 (x p ) modulated by the reward s(x) and the agent log-likelihood log p ψ (x p ) of the generated molecules in P. The agent log-likelihood log p ψ (x p ) refers to the probability of generating a SMILES sequence x p token by token, computed as log p ψ (x p ) = T t=1 log p(x t | x t-1 , . . . , x 1 ), where each x t is a token in the sequence. The influence of s(x) is controlled by the pre-defined hyperparameter λ.