use normal distribution for accuracy

1 files changed, 36 insertions, 25 deletions

diff --git a/dartbot.rb b/dartbot.rb
index ccf5e38..facd745 100755
--- a/dartbot.rb
+++ b/dartbot.rb
@@ -1,7 +1,7 @@
 #!/usr/bin/env ruby
 
-HORIZONTAL_ACCURACY = 32.0
-VERTICAL_ACCURACY = 32.0
+HORIZONTAL_STDEV = 24
+VERTICAL_STDEV = 24
 
 # board spec from WDF rules
 WIRE_WIDTH = 1.56
@@ -42,10 +42,17 @@ def get_coordinates(angle, radius)
   [x, y]
 end
 
+def gauss
+  theta = 2 * Math::PI * rand
+  r = Math.sqrt(-2 * Math.log(1 - rand))
+  [r * Math.cos(theta), r * Math.sin(theta)]
+end
+
 def throw_dart(angle, radius)
   x, y = get_coordinates(angle, radius)
-  x += rand(-HORIZONTAL_ACCURACY..HORIZONTAL_ACCURACY)
-  y += rand(-VERTICAL_ACCURACY..VERTICAL_ACCURACY)
+  x_offset, y_offset = gauss
+  x += HORIZONTAL_STDEV * x_offset
+  y += VERTICAL_STDEV * y_offset
 
   d_angle = Math.atan2(y, x) * 180 / Math::PI
   d_radius = Math.sqrt(x**2 + y**2)
@@ -164,23 +171,23 @@ def play_visit(rem)
   [v_rem, rem - v_rem, darts, bust]
 end
 
-def colour_score(score)
-  scor = "%3s" % score
-
-  if score == 180
-    "\e[1;38;5;82m#{scor}\e[0m"
-  elsif score > 139
-    "\e[38;5;82m#{scor}\e[0m"
-  elsif score > 99
-    "\e[38;5;154m#{scor}\e[0m"
-  elsif score > 59
-    "\e[38;5;226m#{scor}\e[0m"
-  elsif score > 39
-    "\e[38;5;214m#{scor}\e[0m"
-  elsif score > 19
-    "\e[38;5;202m#{scor}\e[0m"
+def colour_points(points)
+  str = "%3s" % points
+
+  if points == 180
+    "\e[1;38;5;82m#{str}\e[0m"
+  elsif points > 139
+    "\e[38;5;82m#{str}\e[0m"
+  elsif points > 99
+    "\e[38;5;154m#{str}\e[0m"
+  elsif points > 59
+    "\e[38;5;226m#{str}\e[0m"
+  elsif points > 39
+    "\e[38;5;214m#{str}\e[0m"
+  elsif points > 19
+    "\e[38;5;202m#{str}\e[0m"
   else
-    "\e[38;5;196m#{scor}\e[0m"
+    "\e[38;5;196m#{str}\e[0m"
   end
 end
 
@@ -192,7 +199,7 @@ end
 
 def output_visit(n, rem, points = nil, darts = nil, bust = false)
   str = '(%2s)  %3s' % [n, rem]
-  str << '  %s' % colour_score(points) if points
+  str << '  %s' % colour_points(points) if points
   str << "    \e[38;5;235m%s\e[0m" % visit_darts(darts) if darts
   str << " \e[38;5;88mBUST\e[0m" if bust
   str << " \e[38;5;76mWIN\e[0m" if rem.zero?
@@ -207,10 +214,10 @@ def play_match(start_points = 501, output = true)
   output_visit(m_darts.length, rem) if output
 
   while rem != 0
-    rem, score, darts, bust = play_visit(rem)
+    rem, points, darts, bust = play_visit(rem)
     m_darts << darts
 
-    output_visit(m_darts.length, rem, score, darts, bust) if output
+    output_visit(m_darts.length, rem, points, darts, bust) if output
 
     if rem.zero? && output
       puts
@@ -224,14 +231,18 @@ def play_match(start_points = 501, output = true)
 end
 
 def test_average
-  averages = (0..10000).map do |x|
+  avgs = (0..10000).map do |x|
     m_darts = play_match(501, false)
     req = (((m_darts.length - 1) * 3) + m_darts[-1].length)
     (501.to_f / req * 3)
   end
 
+  avg = avgs.sum / avgs.length
+  stdev = Math.sqrt(avgs.sum { |x| (x - avg) ** 2 } / (avgs.length - 1))
+
   puts
-  puts averages.inject { |sum, x| sum += x } / averages.length
+  puts avg
+  puts stdev
 end
 
 play_match