6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
|
# File 'lib/rsemantic/transform/tf_idf_transform.rb', line 6
def self.transform!(matrix)
number_of_documents = matrix.size2
@@number_of_documents_with_term = []
matrix.transpose.enum_for(:each_row).with_index do |document, column_index|
document.enum_for(:each).with_index do |term_weight, row_index|
unless term_weight == 0.0
inverse_document_frequency = 1 + GSL::Sf.log(number_of_documents / (number_of_documents_with_term(row_index, matrix).to_f + 1))
term_frequency = Math.sqrt(term_weight)
matrix[row_index, column_index] = term_frequency * inverse_document_frequency
end
end
end
end
|