Method: TfIdfSimilarity::TfIdfModel#probabilistic_inverse_document_frequency

Defined in:
lib/tf-idf-similarity/extras/tf_idf_model.rb

#probabilistic_inverse_document_frequency(term) ⇒ Object Also known as: probabilistic_idf

SMART p, Salton p, Chisholm IDFP

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# File 'lib/tf-idf-similarity/extras/tf_idf_model.rb', line 31

def probabilistic_inverse_document_frequency(term)
  count = @model.document_count(term).to_f
  log((documents.size - count) / count)
end