However, in molecular simulations, a complete sampling of the free volume can be extremely cumbersome. Therefore, random samplings are used to reduce simulation time, for example in the Widom insertion method. Still, convergence of the random sampling of space requires a large number of samples, and most of the points may not contribute significantly to the Boltzmann average (i.e., they might have high energy). It is possible to reduce the computational cost further by reducing the number of sampled points, to try and capture only those with the highest contribution to the actual value of enthalpy. But, how can we choose these points a priori, without first calculating their energy?