refactoring (some formatting, mostly ruby'ization)

rb/glicko2.rb

@@ -108,8 +108,8 @@ class Glicko2
   # and/or add_draw().  This method is called automatically whenever update()
   # is called.
   def clear_results
-    @opponents = []
+    @opponents = Array.new
-    @results = []
+    @results   = Array.new
   end
 
   # Add a result to this rating.  Note that no calculation is performed until
@@ -156,28 +156,16 @@ class Glicko2
     end
 
     # compute variance
-
+    variance = 1.0 / @results.inject(0.0) do |sum,r|
-    #variance = 0.0
-    #@results.inject(0.0) do |variance,r|
-    # g_i = Glicko2.g(r.opponent.g2deviation)
-    # e_i = Glicko2.E(@g2rating,r.opponent.g2rating,r.opponent.g2deviation)
-    # g_i ** 2.0 * e_i * (1.0 - e_i)
-    #end
-
-    variance = 0.0
-    @results.each do |r|
       g_i = Glicko2.g(r.opponent.g2deviation)
       e_i = Glicko2.E(@g2rating, r.opponent.g2rating, r.opponent.g2deviation)
-      variance += g_i ** 2.0 * e_i * (1.0 - e_i)
+      sum + g_i**2.0 * e_i * (1.0 - e_i)
     end
-    variance = 1.0 / variance
 
     # compute delta
-    delta = 0.0
+    delta = variance * @results.inject(0.0) do |sum,r|
-    @results.each do |r|
+      sum + Glicko2.g(r.opponent.g2deviation) * (r.result - Glicko2.E(@g2rating, r.opponent.g2rating, r.opponent.g2deviation))
-      delta += Glicko2.g(r.opponent.g2deviation) * (r.result - Glicko2.E(@g2rating, r.opponent.g2rating, r.opponent.g2deviation))
     end
-    delta *= variance
 
     # determine new volatility
     new_volatility = 0.0
@@ -198,12 +186,9 @@ class Glicko2
 
     # update the rating and deviation
     new_deviation = 1.0 / (Math.sqrt(1.0/(pre_deviation**2.0) + 1.0 / variance))
-    new_rating    = 0.0
+    new_rating    = @g2rating + new_deviation**2.0 * @results.inject(0.0) do |sum,r|
-    @results.each do |r|
+      sum + Glicko2.g(r.opponent.g2deviation) * (r.result - Glicko2.E(@g2rating, r.opponent.g2rating, r.opponent.g2deviation))
-      new_rating += Glicko2.g(r.opponent.g2deviation) * (r.result - Glicko2.E(@g2rating, r.opponent.g2rating, r.opponent.g2deviation))
     end
-    new_rating  = new_rating * new_deviation**2.0
-    new_rating += @g2rating
 
     # wipe our result lists
     clear_results