107 lines
2.4 KiB
Ruby
107 lines
2.4 KiB
Ruby
module Similarity
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class Calc
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def self.call model, tgt
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similarity_model = "#{ model.name }Similarity".constantize
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# 最大保存件数
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n = 20
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similarity_model.delete_all
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posts = model.includes(tgt).select(:id).to_a
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tag_ids = { }
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tag_cnts = { }
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posts.each do |p|
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arr = p.public_send(tgt).map(&:id).sort
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tag_ids[p.id] = arr
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tag_cnts[p.id] = arr.size
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end
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intersection_size = -> a, b do
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i = 0
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j = 0
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cnt = 0
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while i < a.size && j < b.size
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a_i = a[i]
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b_j = b[j]
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if a_i == b_j
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cnt += 1
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i += 1
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j += 1
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elsif a_i < b_j
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i += 1
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else
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j += 1
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end
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end
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cnt
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end
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push_topk = -> list, cos, target_id do
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return if list.size >= n && cos <= list[-1][0]
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idx = nil
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list.each_with_index do |(c, tid), i|
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if tid == target_id
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idx = i
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break
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end
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end
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if idx
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return if cos <= list[idx][0]
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list.delete_at(idx)
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end
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insert_at = list.size
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list.each_with_index do |(c, _), i|
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if cos > c
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insert_at = i
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break
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end
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end
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list.insert(insert_at, [cos, target_id])
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list.pop if list.size > n
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end
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top = Hash.new { |h, key| h[key] = [] }
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ids = posts.map(&:id)
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ids.each_with_index do |post_id, i|
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a = tag_ids[post_id]
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a_cnt = tag_cnts[post_id]
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((i + 1)...ids.size).each do |j|
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target_id = ids[j]
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b = tag_ids[target_id]
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b_cnt = tag_cnts[target_id]
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norm = Math.sqrt(a_cnt * b_cnt)
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cos = norm.zero? ? 0.0 : intersection_size.(a, b).fdiv(norm)
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push_topk.(top[post_id], cos, target_id)
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push_topk.(top[target_id], cos, post_id)
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end
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end
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buf = []
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flush = -> do
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return if buf.empty?
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similarity_model.insert_all!(buf)
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buf.clear
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end
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top.each do |post_id, list|
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list.each do |cos, target_post_id|
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buf << { "#{ model.name.underscore }_id".to_sym => post_id,
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"target_#{ model.name.underscore }_id".to_sym => target_post_id,
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cos: }
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flush.call if buf.size >= 1_000
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end
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end
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flush.call
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end
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end
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end
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