Evaluation Criteria. There are two important measures to evaluate the molecule manipulation task: smooth structure change and smooth property change. To be specific, we design two new evaluation metrics named strict success rate (SSR) and relaxed success rate (RSR) that measure the quality of the identified latent direction in controlling the molecular property. Under strict success rate, we consider a manipulation path to be successful only if we generate molecules with monotonically-changing properties and structures in consecutive k steps of manipulation. While this criteria is rather strict, we propose an alternative relaxed success rate that tolerates a small deviation along the manipulation path, detailed in Appendix A.