Fix Nydegger.

Author: drvinceknight

axelrod/strategies/_strategies.py

@@ -11,7 +11,7 @@
     FirstByGraaskamp,
     FirstByGrofman,
     FirstByJoss,
-    Nydegger,
+    FirstByNydegger,
     RevisedDowning,
     Shubik,
     SteinAndRapoport,
@@ -370,7 +370,7 @@
     Negation,
     NiceAverageCopier,
     NTitsForMTats,
-    Nydegger,
+    FirstByNydegger,
     OmegaTFT,
     OnceBitten,
     OppositeGrudger,

axelrod/strategies/axelrod_first.py

@@ -413,10 +413,26 @@ def __init__(self, p: float = 0.9) -> None:
         super().__init__(four_vector)
 
 
-class Nydegger(Player):
+class FirstByNydegger(Player):
     """
     Submitted to Axelrod's first tournament by Rudy Nydegger.
 
+    The description written in [Axelrod1980]_ is:
+
+    > "The program begins with tit for tat for the first three moves, except
+    > that if it was the only one to cooperate on the first move and the only one
+    > to defect on the second move, it defects on the third move. After the third
+    > move, its choice is determined from the 3 preceding outcomes in the
+    > following manner. Let A be the sum formed by counting the other's defection
+    > as 2 points and one's own as 1 point, and giving weights of 16, 4, and 1 to
+    > the preceding three moves in chronological order. The choice can be
+    > described as defecting only when A equals 1, 6, 7, 17, 22, 23, 26, 29, 30,
+    > 31, 33, 38, 39, 45, 49, 54, 55, 58, or 61. Thus if all three preceding moves
+    > are mutual defection, A = 63 and the rule cooperates.  This rule was
+    > designed for use in laboratory experiments as a stooge which had a memory
+    > and appeared to be trustworthy, potentially cooperative, but not gullible
+    > (Nydegger, 1978)."
+
     The program begins with tit for tat for the first three moves, except
     that if it was the only one to cooperate on the first move and the only one
     to defect on the second move, it defects on the third move. After the
@@ -450,7 +466,7 @@ class Nydegger(Player):
     - Nydegger: [Axelrod1980]_
     """
 
-    name = "Nydegger"
+    name = "First tournament by Nydegger"
     classifier = {
         "memory_depth": 3,
         "stochastic": False,
@@ -462,7 +478,7 @@ class Nydegger(Player):
     }
 
     def __init__(self) -> None:
-        self.As = [1, 6, 7, 17, 22, 23, 26, 29, 30, 31, 33, 38, 39, 45, 54, 55, 58, 61]
+        self.As = [1, 6, 7, 17, 22, 23, 26, 29, 30, 31, 33, 38, 39, 45, 49, 54, 55, 58, 61]
         self.score_map = {(C, C): 0, (C, D): 2, (D, C): 1, (D, D): 3}
         super().__init__()
 

axelrod/tests/strategies/test_axelrod_first.py

@@ -304,10 +304,10 @@ def test_strategy(self):
         self.versus_test(axelrod.Defector(), expected_actions=actions, seed=2)
 
 
-class TestNydegger(TestPlayer):
+class TestFirstByNydegger(TestPlayer):
 
-    name = "Nydegger"
-    player = axelrod.Nydegger
+    name = "First tournament by Nydegger"
+    player = axelrod.FirstByNydegger
     expected_classifier = {
         "memory_depth": 3,
         "stochastic": False,

docs/reference/overview_of_strategies.rst

@@ -18,7 +18,7 @@ An indication is given as to whether or not this strategy is implemented in the
 
   "Tit For Tat", "Anatol Rapoport", ":class:`TitForTat <axelrod.strategies.titfortat.TitForTat>`"
   "Tideman and Chieruzzi", "T Nicolaus Tideman and Paula Chieruzz", ":class:`TidemanAndChieruzzi <axelrod.strategies.axelrod_first.TidemanAndChieruzzi>`"
-  "Nydegger", "Rudy Nydegger", ":class:`Nydegger <axelrod.strategies.axelrod_first.Nydegger>`"
+  "Nydegger", "Rudy Nydegger", ":class:`Nydegger <axelrod.strategies.axelrod_first.FirstByNydegger>`"
   "Grofman", "Bernard Grofman", ":class:`Grofman <axelrod.strategies.axelrod_first.FirstByGrofman>`"
   "Shubik", "Martin Shubik", ":class:`Shubik <axelrod.strategies.axelrod_first.Shubik>`"
   "Stein and Rapoport", "Stein and Anatol Rapoport", ":class:`SteinAndRapoport <axelrod.strategies.axelrod_first.SteinAndRapoport>`"