Module: Suggestor::Algorithms::RecommendationAlgorithm

Included in:
EuclideanDistance, PearsonCorrelation
Defined in:
lib/suggestor/algorithms/recommendation_algorithm.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#collection ⇒ Object

Returns the value of attribute collection.



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# File 'lib/suggestor/algorithms/recommendation_algorithm.rb', line 5

def collection
  @collection
end

Instance Method Details

#initialize(collection) ⇒ Object 



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# File 'lib/suggestor/algorithms/recommendation_algorithm.rb', line 7

def initialize(collection)
  @collection = Records.new(collection)
end

#items_for_set(set, opts = {}) ⇒ Object

Takes a set and returns suggestions based on the weighted average of the similarities to all of the items in it.



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# File 'lib/suggestor/algorithms/recommendation_algorithm.rb', line 47

def items_for_set(set, opts={})
  opts.merge!(default_options)

  suggestions = Hash.new(0.0)

  set.each do |item|
    related = similar_related_to(item, opts)
    related.each { |rel| suggestions[rel[0]] += rel[1] unless
      set.include? rel[0] }
  end

  suggestions = suggestions.map { |label, score| [label, score / set.length] }
  suggestions.sort_by { |sug| sug[1] }.reverse
end

#recommended_to(main, opts = {}) ⇒ Object

Ex. a user will get movie recommendations



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# File 'lib/suggestor/algorithms/recommendation_algorithm.rb', line 23

def recommended_to(main, opts={})
  opts.merge!(default_options)

  @similarities = @totals = Hash.new(0)

  create_similarities_totals(main)

  results = generate_rankings

  sort_results(results,opts[:size])
end

#similar_related_to(main, opts = {}) ⇒ Object

Ex. what other movies are related to a given one



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# File 'lib/suggestor/algorithms/recommendation_algorithm.rb', line 36

def similar_related_to(main, opts={})
  opts.merge!(default_options)

  inverted_collection = @collection.invert
  suggestor     = self.class.new(inverted_collection)
  
  suggestor.similar_to(main,opts)
end

#similar_to(main, opts = {}) ⇒ Object

Ex. Similar users based on their movies reviews



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# File 'lib/suggestor/algorithms/recommendation_algorithm.rb', line 12

def similar_to(main, opts={})
  opts.merge!(default_options)
  
  cleaned = @collection.remove(main)

  results = order_by_similarity_score(main, cleaned)

  sort_results(results,opts[:size])
end