!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!! !!!!! !!!!! VERIFICATION CHECK: vc-inversion-symmetry !!!!! !!!!! !!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Description: Check whether a model is invariant with respect to the inversion operation where each atom is moved along a straight line through the inversion center to a point of equal distance on the other side. This is satisfied for all inversion centers if the model is invariant to rigid-body translation, and has inversion symmetry about the origin. Invariance symmetry is expected from the properties of the quantum mechanics Hamiltonian operator. It should be true for any model that does not depend on an external field. The check is performed for a randomly distorted non-periodic body- centered cubic (BCC) cube base structure. Separate configurations are tested for each species supported by the model, as well as one containing a random distribution of all species. The energy and forces of each configuration are compared with those of the same configuration translated in a random direction by an irrational distance and then inverted through the origin. The energies must be the same and the forces must change sign. The verification check will pass if the energy of all configurations that the model is able to compute pass both tests. Configurations used for testing are provided as auxiliary files. Author: Ellad Tadmor ------------------------------------------------------------------------------------------------------------------------- Results for KIM Model : Sim_LAMMPS_AGNI_BotuBatraChapman_2017_Al__SM_666183636896_000 Supported species : Al random seed = 13 lattice constant (orig) = 3.000 perturbation amplitude = 0.300 number unit cells per side = 2 ------------------------------------------------------------------------------------------------------------------------- WARNING: The model provided, Sim_LAMMPS_AGNI_BotuBatraChapman_2017_Al__SM_666183636896_000, does not possess a non-trivial energy interaction for species Al as required by this Verification Check. Skipping... ERROR: Failed to compute all configurations for the inversion symmetry verification check. ERROR: Unable to perform verification check. Message = ERROR: Failed to compute all configurations for the inversion symmetry verification check.