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attempt to be a bit more expressive by extracting a method for fiding relevant user ids" #92

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attempt to be a bit more expressive by extracting a method for fiding relevant user ids" #92

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46 changes: 23 additions & 23 deletions lib/recommendable/helpers/calculations.rb
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Expand Up @@ -55,29 +55,8 @@ def similarity_between(user_id, other_user_id)
def update_similarities_for(user_id)
user_id = user_id.to_s # For comparison. Redis returns all set members as strings.
similarity_set = Recommendable::Helpers::RedisKeyMapper.similarity_set_for(user_id)

# Only calculate similarities for users who have rated the items that
# this user has rated
relevant_user_ids = Recommendable.config.ratable_classes.inject([]) do |memo, klass|
liked_set = Recommendable::Helpers::RedisKeyMapper.liked_set_for(klass, user_id)
disliked_set = Recommendable::Helpers::RedisKeyMapper.disliked_set_for(klass, user_id)

item_ids = Recommendable.redis.sunion(liked_set, disliked_set)

unless item_ids.empty?
sets = item_ids.map do |id|
liked_by_set = Recommendable::Helpers::RedisKeyMapper.liked_by_set_for(klass, id)
disliked_by_set = Recommendable::Helpers::RedisKeyMapper.disliked_by_set_for(klass, id)

[liked_by_set, disliked_by_set]
end

memo | Recommendable.redis.sunion(*sets.flatten)
else
memo
end
end

relevant_user_ids = relevant_user_ids_for(user_id)

similarity_values = relevant_user_ids.map { |id| similarity_between(user_id, id) }
Recommendable.redis.pipelined do
relevant_user_ids.zip(similarity_values).each do |id, similarity_value|
Expand All @@ -95,6 +74,27 @@ def update_similarities_for(user_id)

true
end

# Calculate similarities for users who have rated the items as user_id
def relevant_user_ids_for(user_id)
relevant_user_ids = Recommendable.config.ratable_classes.each_with_object(Set.new) do |klass, memo|
liked_set = Recommendable::Helpers::RedisKeyMapper.liked_set_for(klass, user_id)
disliked_set = Recommendable::Helpers::RedisKeyMapper.disliked_set_for(klass, user_id)
item_ids = Recommendable.redis.sunion(liked_set, disliked_set)

next if item_ids.empty?
sets = item_ids.map do |id|
liked_by_set = Recommendable::Helpers::RedisKeyMapper.liked_by_set_for(klass, id)
disliked_by_set = Recommendable::Helpers::RedisKeyMapper.disliked_by_set_for(klass, id)

[liked_by_set, disliked_by_set]
end

memo.merge(Recommendable.redis.sunion(*sets.flatten))
end

relevant_user_ids.to_a
end

# Used internally to update this user's prediction values across all
# recommendable types. This is called by the background worker.
Expand Down