where n i and v i are the stoichiometry and the vector representation of the species, i, in the composition X, respectively. V X is the CBFV which represents the composition. Typically, the pooling operation, f p , can be a combination of summary statistics such as the mean, variance, sum, maximum and minimum of the vectors. In this study, we create the CBFVs using the mean, maximum, and sum of the element/species vectors. Max pooling takes the maximum value of each component in the vector representations: