However, as the size of each partition increases, this ratio increases to 1, since most n-grams have a non-zero probability of appearing in each partition.
an alternative is to compute the normalized entropy of the n-gram distribution across the S partitions, or h is the fraction of an n-gram appearing in partition s. For example, the normalized entropy of the unigram C is h(C) = −1 log 3 [ 2 6 log 2 6 + 4 6 log 4 6 + 0] = .58.