Figure : (a) compares the number of steps needed to reach 5,000 molecules for the GSK3β+JNK3+QED+SA task for different ablation models. Using the VQ-VAE greatly improves the efficiency of the model (71k vs 122k steps). (b, c) plots the t-SNE embedding of fragments from generated compounds of our model vs. Rational-RL and MARS. The visualization shows that that our model produces a much more diverse set of fragments, which is a proxy for functional groups appearing in generated molecules.