Model Extended KIM ID = === Verification check vc-objectivity start (2021-04-11 17:15:15) === !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!! !!!!! !!!!! VERIFICATION CHECK: vc-objectivity !!!!! !!!!! !!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Description: Check whether a model is invariant with respect to rigid-body motion (translation and rotation) as required by objectivity (material frame-indifference). This is expected to 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 is compared with that of the same configuration rotated about a random axis by an irrational angle and translated in a random direction by an irrational distance. The verification check will pass if the energy of all configurations that the model is able to compute are invariant and the forces are mapped back by the inverse rotation. Configurations used for testing are provided as auxiliary files. Author: Ellad Tadmor ------------------------------------------------------------------------------------------------------------------------ Results for KIM Model : SNAP_ZuoChenLi_2019quadratic_Li__MO_041269750353_000 Supported species : Li random seed = 13 lattice constant (orig) = 3.000 perturbation amplitude = 0.300 number unit cells per side = 2 ------------------------------------------------------------------------------------------------------------------------ MONOATOMIC STRUCTURE -- Species = Li (Configuration in file "config-Li.xyz") ------------------------------------------------------------------------------------------------------------------------ Rotation matrix = 4.87881115e-01 -8.67485781e-01 -9.71619092e-02 -7.81840872e-01 -3.84765444e-01 -4.90591891e-01 3.88196945e-01 3.15315671e-01 -8.65955634e-01 Translation vector = 2.11123785e+00 5.87684136e-01 -2.25097901e+00 Energy requirement: V(Q*r_1+c,...,Q*r_N+c) = V(r_1,...,r_N), where r_i is the position of atom i, V is the potential energy, Q is a rotation, and c is a translation vector. V(Q*r_1+c,...,Q*r_N+c) = -18.981033349441567 V(Q*r_1,...,Q*r_N) = -18.981033349441567 V(r_1,...,r_N) = -18.981033349441578 Forces requirement: f_i(Q*r_1+c,...,Q*r_N+c) = Q*f_i(r_1,...,r_N), where r_i is the position of atom i, f_i is the force on atom i, Q is a rotation matrix, and c is a translation vector. i f_i(Q*r_1+c,...,Q*r_N+c) Q*f_i(r_1,...,r_N) ------------------------------------------------------------------------------------------------------------------------ 0 2.66140167e-01 6.33737051e-01 4.48893131e-02 | 2.66140167e-01 6.33737051e-01 4.48893131e-02 1 -1.23117998e+00 2.92261450e-01 -3.56675138e-01 | -1.23117998e+00 2.92261450e-01 -3.56675138e-01 2 1.47819181e+00 6.30724206e-01 6.17641057e-01 | 1.47819181e+00 6.30724206e-01 6.17641057e-01 3 7.28029572e-01 -1.15757815e+00 7.16258353e-01 | 7.28029572e-01 -1.15757815e+00 7.16258353e-01 4 -3.74766108e-01 1.06432388e+00 8.34027559e-02 | -3.74766108e-01 1.06432388e+00 8.34027559e-02 5 -2.89356984e+00 -1.05783262e-01 1.65500801e-01 | -2.89356984e+00 -1.05783262e-01 1.65500801e-01 6 1.10871350e+00 1.35232511e-01 2.55369030e+00 | 1.10871350e+00 1.35232511e-01 2.55369030e+00 7 -1.06854537e-01 -6.22105402e-01 3.20721620e-01 | -1.06854537e-01 -6.22105402e-01 3.20721620e-01 8 8.94788230e-02 1.11180948e+00 -8.89841153e-01 | 8.94788230e-02 1.11180948e+00 -8.89841153e-01 9 -1.32047151e-01 -6.56634891e-01 -1.03778394e+00 | -1.32047151e-01 -6.56634891e-01 -1.03778394e+00 10 1.72083820e+00 1.57143860e-01 -7.85712518e-01 | 1.72083820e+00 1.57143860e-01 -7.85712518e-01 11 -6.37591017e-02 -7.67632339e-01 -1.38786324e-01 | -6.37591017e-02 -7.67632339e-01 -1.38786324e-01 12 -6.51658539e-01 9.12201041e-01 -5.37953703e-01 | -6.51658539e-01 9.12201041e-01 -5.37953703e-01 13 -7.36602048e-01 -4.42434297e-01 -6.11875342e-01 | -7.36602048e-01 -4.42434297e-01 -6.11875342e-01 14 8.42892515e-01 -3.83094505e-01 -8.61123529e-02 | 8.42892515e-01 -3.83094505e-01 -8.61123529e-02 15 -4.38472909e-02 -8.02170628e-01 -5.73637295e-02 | -4.38472909e-02 -8.02170628e-01 -5.73637295e-02 ------------------------------------------------------------------------------------------------------------------------ PASS: Energies and forces are the same to within a relative error of 1e-08 ------------------------------------------------------------------------------------------------------------------------ ======================================================================================================================== To pass this verification check the model must be invariant with respect to rigid-body motion (translation and rotation) for all configurations it was able to compute. Grade: P Comment: Model energy and forces are invariant with respect to rigid-body motion (translation and rotation) for all configurations the model was able to compute. === Verification check vc-objectivity end (2021-04-11 17:15:15) ===