lib/field_test/calculations.rb in field_test-0.2.0 vs lib/field_test/calculations.rb in field_test-0.2.1

@@ -1,8 +1,9 @@
+require "distribution/math_extension"
+
 # formulas from
 # http://www.evanmiller.org/bayesian-ab-testing.html
-
 module FieldTest
   module Calculations
     def self.prob_b_beats_a(alpha_a, beta_a, alpha_b, beta_b)
       total = 0.0
 
@@ -25,17 +26,15 @@
       # for performance
       logbeta_ac_bc = Math.logbeta(alpha_c, beta_c)
       abc = beta_a + beta_b + beta_c
       log_bb_j = []
       logbeta_j_bb = []
+      logbeta_ac_i_j = []
       0.upto(alpha_b - 1) do |j|
         log_bb_j[j] = Math.log(beta_b + j)
         logbeta_j_bb[j] = Math.logbeta(1 + j, beta_b)
-      end
 
-      logbeta_ac_i_j = []
-      0.upto(alpha_a - 1) do |i|
-        0.upto(alpha_b - 1) do |j|
+        0.upto(alpha_a - 1) do |i|
           logbeta_ac_i_j[i + j] ||= Math.logbeta(alpha_c + i + j, abc)
         end
       end
 
       0.upto(alpha_a - 1) do |i|