Convergence criteria

Energy convergence is measured per atom over a tail of at least three k-point calculations.

Label	Maximum energy variation
Medium	5 meV/atom
Well	3 meV/atom
Ultra	1 meV/atom

For each label, the selected kindex is the smallest point whose remaining tail satisfies the threshold. The oscillation is max - min over the whole tail, so a longer sweep can only make a label harder to earn, never easier.

These three numbers are the ones the published records used. ConvergenceThresholds in the package defaults to 10 / 5 / 1 meV per atom, so pass them explicitly when reproducing a record rather than relying on the defaults.

Kindex meaning

Kindex follows the current gamma-inclusive schedule. For one structure, an index maps deterministically to one distinct k-point mesh. Because lattice geometry changes that mapping, comparisons between pseudopotential families use the actual mesh dimensions rather than assuming that equal numerical kindices mean equal meshes.

Changing the schedule changes the scientific data contract and requires regenerating dependent training data and models.