Add fuctions to compute the state distribution for a match

Author: theref

axelrod/interaction_utils.py

@@ -9,6 +9,7 @@
 interactions.
 """
 import csv
+from collections import Counter
 
 from .game import Game
 from axelrod import Actions
@@ -87,6 +88,29 @@ def compute_normalised_cooperation(interactions):
     return normalised_cooperation
 
 
+def compute_state_distribution(interactions):
+    """
+    Returns the count of each state for a set of interactions.
+    """
+    if len(interactions) == 0:
+        return None
+    return Counter(interactions)
+
+
+def compute_normalised_state_distribution(interactions):
+    """
+    Returns the normalized count of each state for a set of interactions.
+    """
+    normalized_count = Counter(interactions)
+    total = sum(normalized_count.values(), 0.0)
+    # By starting the sum with 0.0 we make sure total is a floating point value,
+    # avoiding the Python 2 floor division behaviour of / with integer operands (Stack Overflow)
+
+    for key in normalized_count:
+        normalized_count[key] /= total
+    return normalized_count
+
+
 def sparkline(actions, c_symbol=u'█', d_symbol=u' '):
     return u''.join([
         c_symbol if play == 'C' else d_symbol for play in actions])

axelrod/match.py

@@ -159,6 +159,12 @@ def normalised_cooperation(self):
         """Returns the count of cooperations by each player per turn"""
         return iu.compute_normalised_cooperation(self.result)
 
+    def state_distribution(self):
+        return iu.compute_state_distribution(self.result)
+
+    def normalised_state_distribution(self):
+        return iu.compute_normalised_state_distribution(self.result)
+
     def sparklines(self, c_symbol=u'█', d_symbol=u' '):
         return iu.compute_sparklines(self.result, c_symbol, d_symbol)