Also, one would expect this trend to be more pronounced the more focused the agent gets over the course of the training. In order to quantify this behaviour, the average linkage similarity (Tanimoto) between every 5 epochs has been calculated (see Methods for details) for every REINVENT-DockStream experiment (See Supporting Information Fig. ). Fig. shows the resulting Tanimoto matrix for the GOLD experiment displayed in Fig. and Fig. . Firstly, the main diagonal of the Tanimoto matrix is darker (indicating higher similarity) relative to surrounding epochs and gradually becomes even darker, which indicates increased intra-batch similarity as the agent increasingly focuses on regions in chemical space. Moreover, the transition between the lighter shaded top left corner to the darker shaded bottom right corner exemplifies balance between agent exploration and exploitation. By crossreferencing the REINVENT-DockStream training plot for GOLD docking (Fig. ), one can identify that the GOLD docking score begins to converge at around epoch 275. At around epoch 55 in Fig. (corresponds to epoch 275), the Tanimoto matrix gradually becomes darker shaded, indicating increased Tanimoto similarity within the same batch and neighbouring epochs batches (Fig. ). The results demonstrate policy update, reaching a state of productivity and enforcing the agent to begin exploitation of chemical space. Furthermore, even once exploitation begins, the Tanimoto similarities do not converge to 1. The agent continues to explore chemical space as necessitated by the DF applied. In addition, one can observe that the Tanimoto similarities corresponding to surrounding epochs is greater (on average), further supporting gradual and iterative policy update. The results show that REINVENT achieves both chemical space exploration and exploitation and enforces sampling of numerous local minima.