Recently, we developed the GrAED algorithm that efficiently computes energy grids in nanoporous materials: we divide the unit cell into small voxels, whose size is typically between 0.1 and 0.2 Å. For each voxel, we compute the host-guest interaction energy that would have a guest molecule placed in the center of that voxel. While this concept is not novel, we recently made strong improvements in its computational efficiency, by using the symmetry of the host framework and excluding from calculations the space occupied by framework atoms. This grid is a discrete representation of the potential energy surface (PES) of a guest molecular inside the framework. From this PES surface representation, the energy minima are determined. Then, in order to determine the values of energy barrier for diffusion, we then needed to develop an algorithm that detects all-connected clusters within the energy grid. A breadth-first search algorithm is employed to label different connected components within a given channel between 𝐸 min and 𝐸 min + 𝑖𝛿𝐸 (at the 𝑖 th iteration). By monitoring changes in the number of connected components between two energy values, the code automatically detects the energy 𝐸 TS at which components reconnect and form a channel (allowing diffusion from one boundary to another). The activation energy 𝐸 a is then calculated as the difference between the calculated transition state energy 𝐸 TS and the minimal energy 𝐸 min within the channel: 𝐸 a = 𝐸 TS -𝐸 min .