FIX: is_dominated: Return False if num_actions == 1

quantecon/game_theory/normal_form_game.py

@@ -420,6 +420,8 @@ def is_dominated(self, action, tol=None, method=None):
  ind[action] = False
  D = payoff_array[ind]
  D -= payoff_array[action]
+ if D.shape[0] == 0: # num_actions == 1
+ return False
  if self.num_opponents >= 2:
  D.shape = (D.shape[0], np.prod(D.shape[1:]))
 

quantecon/game_theory/tests/test_normal_form_game.py

@@ -376,6 +376,24 @@ def test_normalformgame_setitem_1p():
  eq_(g.players[0].payoff_array[0], 10)
 
 
+# Trivial cases with one action #
+
+class TestPlayer_1action:
+ def setUp(self):
+ """Setup a Player instance"""
+ self.payoffs = [[0, 1]]
+ self.player = Player(self.payoffs)
+
+ def test_is_dominated(self):
+ for action in range(self.player.num_actions):
+ for method in LP_METHODS:
+ eq_(self.player.is_dominated(action, method=method), False)
+
+ def test_dominated_actions(self):
+ for method in LP_METHODS:
+ eq_(self.player.dominated_actions(method=method), [])
+
+
 # Test __repr__ #
 
 def test_player_repr():