Interatomic models stored in OpenKIM are now subjected to a suite of
Verification Checks (VCs) that put the models through their paces and check that they are programmed correctly. The following VCs are currently available:
vc-species-supported-as-stated — The model supports all species it claims to support.
vc-periodicity-support — Periodic boundary conditions are handled correctly.
vc-permutation-symmetry — Total energy and forces are unchanged when swapping atoms of the same species.
vc-forces-numerical-derivative — Forces computed by the model agree with numerical derivatives of the energy.
vc-dimer-continuity-c1 — The energy versus separation relation of a pair of atoms is C1 continuous (i.e. the function and its first derivative are continuous).
vc-objectivity — Total energy is unchanged and forces transform correctly under rigid-body translation and rotation.
vc-inversion-symmetry — Total energy is unchanged and forces change sign when inverting a configuration through the origin.
vc-memory-leak — The model code does not have memory leaks (i.e. it releases all allocated memory at the end).
Each model is graded on these VCs and the results are displayed in a dashboard on its model page (as an example, see here). Each VC grade is accompanied by a detailed report and data providing more information on the model, which are accessible through the dashboard. For more information, see About VCs.