Add Tricky Level Punisher (#1178)

* Added Tricky level punisher strategy.

* Update punisher.py

* Removing syntax error

* Removing systax error

* Implementing review changes.

* Implementing review changes.

* Review changes

* fix error division by zero

* tweak meta player test

The behaviour of MetaMajorityLongMemory has now changed because
Tricky Level Punisher is on the strategy's team.

Author: Nikoleta

axelrod/strategies/_strategies.py

@@ -65,7 +65,7 @@
 from .oncebitten import OnceBitten, FoolMeOnce, ForgetfulFoolMeOnce, FoolMeForever
 from .prober import (CollectiveStrategy, Prober, Prober2, Prober3, Prober4,
                      HardProber, NaiveProber, RemorsefulProber)
-from .punisher import Punisher, InversePunisher, LevelPunisher
+from .punisher import Punisher, InversePunisher, LevelPunisher, TrickyLevelPunisher
 from .qlearner import (
     RiskyQLearner, ArrogantQLearner, HesitantQLearner, CautiousQLearner)
 from .rand import Random
@@ -279,6 +279,7 @@
     Tranquilizer,
     TrickyCooperator,
     TrickyDefector,
+    TrickyLevelPunisher,
     Tullock,
     TwoTitsForTat,
     VeryBad,

axelrod/strategies/punisher.py

@@ -143,3 +143,40 @@ def strategy(self, opponent: Player) -> Action:
             return D
         else:
             return C
+
+
+class TrickyLevelPunisher(Player):
+    """
+    A player starts by cooperating however, after 10, 50 and 100 rounds
+    will defect if at any point the percentage of defections
+    by an opponent is greater than 20%, 10% and 5% respectively.
+
+    Names:
+
+    - Tricky Level Punisher: [Eckhart2015]_
+    """
+
+    name = 'Tricky Level Punisher'
+    classifier = {
+        'memory_depth': float('inf'), # Long Memory
+        'stochastic': False,
+        'makes_use_of': set(),
+        'long_run_time': False,
+        'inspects_source': False,
+        'manipulates_source': False,
+        'manipulates_state': False
+    }
+
+    def strategy(self, opponent: Player) -> Action:
+        if len(opponent.history) == 0:
+            return C
+        if len(opponent.history) < 10:
+            if opponent.defections / len(opponent.history) > 0.2:
+                return D
+        if len(opponent.history) < 50:
+            if opponent.defections / len(opponent.history) > 0.1:
+                return D
+        if len(opponent.history) < 100:
+            if opponent.defections / len(opponent.history) > 0.05:
+                return D
+        return C

axelrod/tests/strategies/test_meta.py

@@ -335,7 +335,7 @@ def test_strategy(self):
         self.versus_test(opponent=axelrod.Alternator(),
                          expected_actions=actions, seed=0)
 
-        actions = [(C, C), (C, D), (C, C), (C, D), (D, C)]
+        actions = [(C, C), (C, D), (D, C), (C, D), (D, C)]
         self.versus_test(opponent=axelrod.Alternator(),
                          expected_actions=actions, seed=1)
 

axelrod/tests/strategies/test_punisher.py

@@ -130,3 +130,46 @@ def test_strategy(self):
         opponent = axelrod.MockPlayer([C] * 4 + [D] + [C] * 4 + [D])
         actions = [(C, C)] * 4 + [(C, D)] + [(C, C)] * 4 + [(C, D), (C, C)]
         self.versus_test(opponent=opponent, expected_actions=actions)
+
+
+class TestTrickyLevelPunisher(TestPlayer):
+
+    name = "Level Punisher"
+    player = axelrod.LevelPunisher
+    expected_classifier = {
+        'memory_depth': float('inf'),  # Long memory
+        'stochastic': False,
+        'makes_use_of': set(),
+        'long_run_time': False,
+        'inspects_source': False,
+        'manipulates_source': False,
+        'manipulates_state': False
+    }
+
+    def test_strategy(self):
+        # Cooperates if the turns played are less than 10.
+        actions = [(C, C)] * 9
+        self.versus_test(opponent=axelrod.Cooperator(),
+                         expected_actions=actions)
+
+        # After 10 rounds
+        # Check if number of defections by opponent is greater than 20%
+        opponent = axelrod.MockPlayer([C] * 4 + [D] * 2 + [C] * 3 + [D])
+        actions = [(C, C)] * 4 + [(C, D)] * 2 + [(C, C)] * 3 + [(C, D), (D, C)]
+        self.versus_test(opponent=opponent, expected_actions=actions)
+
+        # Check if number of defections by opponent is greater than 10%
+        opponent = axelrod.MockPlayer([C] * 4 + [D] + [C] * 4 + [D])
+        actions = [(C, C)] * 4 + [(C, D)] + [(C, C)] * 4 + [(C, D), (C, C)]
+        self.versus_test(opponent=opponent, expected_actions=actions)
+
+        # After 10 rounds
+        # Check if number of defections by opponent is greater than 5%
+        opponent = axelrod.MockPlayer([C] * 4 + [D] + [C] * 5)
+        actions = [(C, C)] * 4 + [(C, D)] + [(C, C)] * 5
+        self.versus_test(opponent=opponent, expected_actions=actions)
+
+        # Check if number of defections by opponent is less than 5%
+        opponent = axelrod.MockPlayer([C]*10)
+        actions = [(C, C)] * 5
+        self.versus_test(opponent=opponent, expected_actions=actions)