Active potential is defined as the surprise associated to penalize words which doesn't occur enough
If k is the number of times a word appears as keyword, frequent keywords are promoted, rare keywords (eg misspells and names) are not
If k is the number of times a word appears as keyword, frequent keywords are promoted, rare keywords (eg misspells and names) are not
number of times a word appears as keyword
Builds a Binomial prior. Successes should be Int, but are put Double for more flexibility.
Created by Mario Alemi on 06/04/2017.