Sources of uncertainty. Uncertainty in the Xe/Kr selectivity of a COF may owe to (i) a lack of simulations on COFs in the neighborhood of COF space around x, (ii) a lack of mutual information between outcomes of simulations of different fidelities, (iii) a lack of information about the selectivity contained in the features, and/or (iv) inherent variability/noise in the outcome of the Monte Carlo simulation.