!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!! !!!!! !!!!! VERIFICATION CHECK: vc-forces-numerical-derivative !!!!! !!!!! !!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Description: Comparison of the analytical forces obtained from the model with forces computed by numerical differentiation using Richardson extrapolation for a randomly distorted non-periodic structure based off the equilibrium face-centered cubic (fcc) structure. Separate configurations are tested for each species supported by the model, as well as one containing a random distribution of all species. Configurations used for testing are provided as auxiliary files. Author: Ellad Tadmor ----------------------------------------------------------------------------------------------------- Results for KIM Model : MEAM_LAMMPS_Wagner_2007_Ni__MO_444394830472_001 Supported species : Ni random seed = 13 perturbation amplitude = 0.250 number unit cells per side = 2 ----------------------------------------------------------------------------------------------------- Comparison of analytical forces obtained from the model, the force computed as a numerical derivative of the energy, the difference between them, and the uncertainty in the numerical estimate of the force. The computed equilibrium lattice constant for the crystal (a0) is given in the heading. MONOATOMIC STRUCTURE -- Species = Ni | a0 = 3.520000457763672 | (Configuration in file "config-Ni.xyz") ----------------------------------------------------------------------------------------------------- Part Spec Dir Force_model Force_numer |Force diff| uncertainty ----------------------------------------------------------------------------------------------------- 1 Ni 1 5.334262646662456e+14 -9.213755858154074e+21 9.21376e+21 5.48112e+25 * 1 Ni 2 F 1 Ni 3 F 2 Ni 1 F 2 Ni 2 F 2 Ni 3 F 3 Ni 1 F 3 Ni 2 F 3 Ni 3 F 4 Ni 1 F 4 Ni 2 F 4 Ni 3 F 5 Ni 1 F 5 Ni 2 F 5 Ni 3 F 6 Ni 1 F 6 Ni 2 F 6 Ni 3 F 7 Ni 1 F 7 Ni 2 F 7 Ni 3 F 8 Ni 1 F 8 Ni 2 F 8 Ni 3 F 9 Ni 1 F 9 Ni 2 F 9 Ni 3 F 10 Ni 1 F 10 Ni 2 F 10 Ni 3 F 11 Ni 1 F 11 Ni 2 F 11 Ni 3 F 12 Ni 1 F 12 Ni 2 F 12 Ni 3 F 13 Ni 1 F 13 Ni 2 F 13 Ni 3 F 14 Ni 1 F 14 Ni 2 F 14 Ni 3 F 15 Ni 1 F 15 Ni 2 F 15 Ni 3 F 16 Ni 1 F 16 Ni 2 F 16 Ni 3 F 17 Ni 1 F 17 Ni 2 F 17 Ni 3 F 18 Ni 1 F 18 Ni 2 F 18 Ni 3 F 19 Ni 1 F 19 Ni 2 F 19 Ni 3 F 20 Ni 1 F 20 Ni 2 F 20 Ni 3 F 21 Ni 1 F 21 Ni 2 F 21 Ni 3 F 22 Ni 1 F 22 Ni 2 F 22 Ni 3 F 23 Ni 1 F 23 Ni 2 F 23 Ni 3 F 24 Ni 1 F 24 Ni 2 F 24 Ni 3 F 25 Ni 1 F 25 Ni 2 F 25 Ni 3 F 26 Ni 1 F 26 Ni 2 F 26 Ni 3 F 27 Ni 1 F 27 Ni 2 F 27 Ni 3 F 28 Ni 1 F 28 Ni 2 F 28 Ni 3 F 29 Ni 1 F 29 Ni 2 F 29 Ni 3 F 30 Ni 1 F 30 Ni 2 F 30 Ni 3 F 31 Ni 1 F 31 Ni 2 F 31 Ni 3 F 32 Ni 1 F 32 Ni 2 F 32 Ni 3 F * Starred lines are suspected outliers and are not included when determining the error. A calculation is considered an outlier if it has an uncertainty that lies at an abnormal distance from the other uncertainties in this set of calculations. Outliers are determined using the box plot construction with fences. An outlier could indicate a problem with the the numerical differentiation or problems with the potential energy, such as discontinuities. WARNING: Numerical derivative could not be computed for at least one atom/dof. Failed calculations indicated with an "F". This can be due to attempts to evaluate the model outside its legal range during a numerical derivative. calculation. These lines are ignored when computing the error. ERROR: Failed to compute a single numerical derivative. ERROR: Unable to perform verification check. Message = ERROR: Failed to compute a single numerical derivative.