-𝑈 TOU (𝑛)] ! + Γ ! ∑ 𝐶 V ! V (11) Here, 𝑤 1 are the weights that emphasize the training data with lower total energy, 𝑈 >8ROS is the permutationally invariant polynomial used for fitting the training set (𝑊 ! (𝑑) in Eq. 3 for fitting twobody interactions or ∆𝑊 % (𝑑 4! , 𝑑 4% , 𝑑 !% ) in Eq. 6 for fitting three-body interactions), and 𝑈 TOU is the corresponding reference value in the training set. To avoid overfitting with respect to linear fitting parameters 𝐶 V , the regularization parameter Γ was set to 5 × 10 ,E for fitting two-body interactions and to 10 ,E for fitting three-body interactions. The 𝑤 1 were assigned as follows: