biccount

confirmedupstream bugPython · scikit-gstatSystems & data structuresJuly 25, 2026

the question

Does scikit-gstat's Variogram.bic apply the correct Bayesian information criterion penalty?

what came out

scikit-gstat's Variogram.bic penalises with 2*ln(k), the log of the parameter count, instead of k*ln(n). The sample size never enters, so the penalty is constant in n and sits below AIC, inverting the BIC/AIC relationship. The sibling aic is correct; the fix is k*np.log(n).

method & receipts

Result: confirmed
Reproducible — one script re-runs the whole thing from scratch.
Tested — a correctness/benchmark suite ships alongside the code.

→ read the code and re-run it

github.com/v-code01/biccount