44 lines
1.8 KiB
Ruby
44 lines
1.8 KiB
Ruby
module JamRuby
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class Review < ActiveRecord::Base
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attr_accessible :target, :rating, :description, :user
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belongs_to :target, polymorphic: true
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belongs_to :user, foreign_key: 'user_id', class_name: "JamRuby::User"
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belongs_to :deleted_by_user, foreign_key: 'deleted_by_user_id', class_name: "JamRuby::User"
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validates :rating, presence:true, numericality: {only_integer: true, minimum:1, maximum:5}
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validates :target, presence:true
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validates :user, presence:true
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validates :target_id, uniqueness: {scope: :user_id, message: "There is already a review for this User and Target."}
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class << self
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# Create review_summary records by grouping reviews
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def reduce()
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ReviewSummary.transaction do
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ReviewSummary.destroy_all
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Review.select("target_id, target_type AS target_type, AVG(rating) as avg_rating, count(*) as review_count, SUM(CASE WHEN rating>=3.0 THEN 1 ELSE 0 END) AS pos_count").group("target_type, target_id")
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.each do |r|
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#puts "Reducing reviews: #{r.inspect} #{r.pos_count} / #{r.review_count}"
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ReviewSummary.create!(
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target_id: r.target_id,
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target_type: r.target_type,
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avg_rating: r.avg_rating,
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wilson_score: ci_lower_bound(r.pos_count, r.review_count),
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review_count: r.review_count
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)
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end # each
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end # transaction
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end # reduce
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def ci_lower_bound(pos, n, confidence=0.95)
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pos=pos.to_f
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n=n.to_f
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return 0 if n == 0
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z = 1.96 # Statistics2.pnormaldist(1-(1-confidence)/2)
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phat = 1.0*pos/n
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(phat + z*z/(2*n) - z * Math.sqrt((phat*(1-phat)+z*z/(4*n))/n))/(1+z*z/n)
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end
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end # self
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end
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end |