where X = X DFT X ChIMES{c} and X is a force, energy or stress predicted by the superscripted method. F obj and {c} are the weighted root-mean-squared error and model coefficients, respectively. The number of frames and atoms are given by n f and n a , respectively. F ijk indicates the k th Cartesian component of the force on atom j in configuration i while ij and E i indicates the j component of the stress tensor and the energy for configuration i, respectively. Weights for each force, energy, and stress are given by w.