Class: TextRank::RankFilter::NormalizeUnitVector

Inherits:
Object
  • Object
show all
Defined in:
lib/text_rank/rank_filter/normalize_unit_vector.rb

Overview

A rank filter which normalizes the ranked keywords so that the sum of the squares of the rank values is 1.0 (and thus the keyword rankings in an N-vector space is a unit vector).

= Example

NormalizeUnitVector.new.filter!( { “town” => 0.6818754334834477, “cities” => 0.6055017128817066, “siege” => 0.5411519524982207, “arts” => 0.4907977453782612, “envy” => 0.4692709808107252, “blessings” => 0.4442147897516214, “plagues” => 0.3972420789430091, “florish” => 0.2746092797528525, “devoured” => 0.26867321734332237, “anxieties” => 0.2367731719604189, “peace” => 0.1905352582752693, “inhabitants” => 0.02715120116732137, } ) => { “town” => 0.4616807998499129, “cities” => 0.40997006401243896, “siege” => 0.3664004508761722, “arts” => 0.3323068767754191, “envy” => 0.317731642948694, “blessings” => 0.30076672272820315, “plagues” => 0.2689626751964553, “florish” => 0.18593107435301526, “devoured” => 0.1819119149778339, “anxieties” => 0.16031319218415677, “peace” => 0.12900665740478157, “inhabitants” => 0.01838339916101275, }

Instance Method Summary collapse

Instance Method Details

#filter!(ranks, **_) ⇒ Hash<String, Float>

Perform the filter on the ranks

Parameters:

  • ranks (Hash<String, Float>) —

    the results of the PageRank algorithm

Returns:

  • (Hash<String, Float>) 


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# File 'lib/text_rank/rank_filter/normalize_unit_vector.rb', line 46

def filter!(ranks, **_)
  return if ranks.empty?

  total = Math.sqrt(ranks.values.map { |v| v * v }.reduce(:+))
  ranks.transform_values { |v| v / total }
end