Calculates the TF-IDF
Calculates the TF-IDF.
iex> SimpleBayes.TfIdf.call(2, 0, 1) 2 iex> SimpleBayes.TfIdf.call(2, 1, 0) 2 iex> SimpleBayes.TfIdf.call(2, 1, 1) 2 iex> SimpleBayes.TfIdf.call(2, 2, 1) 0.6020599913279624