move vote similarity code into danbooru, add listing for super voters

app/controllers/super_voters_controller.rb

@@ -0,0 +1,8 @@
+class SuperVotersController < ApplicationController
+  before_filter :member_only
+
+  def index
+    @super_voters = SuperVoter.all
+  end
+end
+

app/logical/post_vote_similarity.rb

@@ -0,0 +1,58 @@
+require "set"
+
+class PostVoteSimilarity
+  class Element
+    attr_reader :user_id, :score
+
+    def initialize(user_id, score)
+      @user_id = user_id
+      @score = score
+    end
+
+    def <=>(rhs)
+      score <=> rhs.score
+    end
+  end
+
+  attr_reader :user_id
+
+  def initialize(user_id)
+    @user_id = user_id
+  end
+
+  # returns user ids with strong negative correlation
+  def calculate_negative(limit = 10)
+    posts0 = PostVote.negative_post_ids(user_id)
+    set = SortedSet.new
+
+    PostVote.positive_user_ids.each do |uid|
+      posts1 = PostVote.positive_post_ids(uid)
+      set.add(Element.new(uid, calculate_with_cosine(posts0, posts1)))
+    end
+
+    set.first(limit)
+  end
+
+  # returns user ids with strong positive correlation
+  def calculate_positive(limit = 10)
+    posts0 = PostVote.positive_post_ids(user_id)
+    set = SortedSet.new
+
+    PostVote.positive_user_ids.each do |uid|
+      posts1 = PostVote.positive_post_ids(uid)
+      set.add(Element.new(uid, calculate_with_cosine(posts0, posts1)))
+    end
+
+    set.first(limit)
+  end
+
+  def calculate_with_cosine(posts0, posts1)
+    a = (posts0 & posts1).size
+    div = Math.sqrt(posts0.size * posts1.size)
+    if div == 0
+      0
+    else
+      a / div
+    end
+  end
+end

app/models/post_vote.rb

@@ -12,6 +12,18 @@ class PostVote < ActiveRecord::Base
     where("created_at < ?", 30.days.ago).delete_all
   end
 
+  def self.positive_user_ids
+    select_values_sql("select user_id from post_votes where score > 0 group by user_id having count(*) > 100")
+  end
+
+  def self.negative_post_ids(user_id)
+    select_values_sql("select post_id from post_votes where score < 0 and user_id = ?", user_id)
+  end
+
+  def self.positive_post_ids(user_id)
+    select_values_sql("select post_id from post_votes where score > 0 and user_id = ?", user_id)
+  end
+
   def score=(x)
     if x == "up"
       Post.where(:id => post_id).update_all("score = score + #{magnitude}, up_score = up_score + #{magnitude}")

app/models/super_voter.rb

@@ -13,18 +13,11 @@ class SuperVoter < ActiveRecord::Base
 
   def self.init!
     prune!
-    report = Reports::UserSimilarity.new(User.admins.first.id)
-    report.prime("post_vote_similarity")
+    report = PostVoteSimilarity.new(User.admins.first.id)
 
-    report.result.scan(/\S+/).in_groups_of(2).each do |user_id, score|
-      unless where("user_id = ?", user_id.to_i).exists?
-        create(:user_id => user_id)
-      end
-    end
-
-    User.admins.each do |user|
-      unless where("user_id = ?", user.id).exists?
-        create(:user_id => user.id)
+    report.calculate_positive.each do |element|
+      unless where("user_id = ?", element.user_id).exists?
+        create(:user_id => element.user_id)
       end
     end
   end

app/views/static/site_map.html.erb

@@ -109,6 +109,7 @@
         <li><%= link_to("Signup", new_user_path) %></li>
         <li><%= link_to("Terms of Service", terms_of_service_path) %></li>
         <li><%= link_to("Upgrade Information", new_user_upgrade_path) %></li>
+        <li><%= link_to("Super Voters", super_voters_path)</li>
       </ul>
       <ul>
         <li><h1>Admin</h1></li>

app/views/super_voters/index.html.erb

@@ -0,0 +1,17 @@
+<div id="c-super-voters">
+  <div id="a-index">
+    <h1>Super Voters</h1>
+
+    <p>The following users will increment or decrement a post's score by <%= SuperVoter::MAGNITUDE %> when they vote. This list is regenerated once a week.</p>
+
+    <ul>
+      <% @super_voters.each do |super_voter| %>
+        <li><%= link_to_if CurrentUser.user.is_janitor?, super_voter.user.name, posts_path(tags: "upvote:#{super_voter.user.name}") %></li>
+      <% end %>
+    </ul>
+  </div>
+</div>
+
+<% content_for(:page_title) do %>
+  Super Voters - <%= Danbooru.config.app_name %>
+<% end %>

config/routes.rb

@@ -243,6 +243,7 @@ Rails.application.routes.draw do
     end
   end
   resource :source, :only => [:show]
+  resources :super_voters, :only => [:index]
   resources :tags do
     resource :correction, :only => [:new, :create, :show], :controller => "tag_corrections"
     collection do