lib/disco/recommender.rb in disco-0.2.7 vs lib/disco/recommender.rb in disco-0.2.8

@@ -183,20 +183,26 @@
       if @implicit
         scores = Numo::UInt64.cast(@item_count)
       else
         require "wilson_score"
 
-        range = @min_rating..@max_rating
+        range =
+          if @min_rating == @max_rating
+            # TODO remove temp fix
+            (@min_rating - 1)..@max_rating
+          else
+            @min_rating..@max_rating
+          end
         scores = Numo::DFloat.cast(@item_sum.zip(@item_count).map { |s, c| WilsonScore.rating_lower_bound(s / c, c, range) })
 
         # TODO uncomment in 0.3.0
         # wilson score with continuity correction
         # https://en.wikipedia.org/wiki/Binomial_proportion_confidence_interval#Wilson_score_interval_with_continuity_correction
         # z = 1.96 # 95% confidence
         # range = @max_rating - @min_rating
         # n = Numo::DFloat.cast(@item_count)
         # phat = (Numo::DFloat.cast(@item_sum) - (@min_rating * n)) / range / n
-        # phat = (phat - (1 / 2 * n)).clip(0, 100) # continuity correction
+        # phat = (phat - (1 / (2 * n))).clip(0, nil) # continuity correction
         # scores = (phat + z**2 / (2 * n) - z * Numo::DFloat::Math.sqrt((phat * (1 - phat) + z**2 / (4 * n)) / n)) / (1 + z**2 / n)
         # scores = scores * range + @min_rating
       end
 
       indexes = scores.sort_index.reverse