In Eq. 3, i and t index distinct beads and configurations, respectively, the N j N t product is the total number of terms in the summation, F AA is the force from the atomistic trajectory, and F ML CG is the force calculated by DeePCG as the derivative of the DNN. The F AA terms were calculated as the net force on each CG bead (i) by summing the atomistic forces (f) on all the atoms ( j ∈ i) constituting it, F AA,i = ∑ j∈i f AA,i . This entails that the F AA terms are specific to each CG mapping, even though the same atomistic data was used for training all models. Distinct DeePCG models were trained for each mapping of butanol and the PEG system studied here.