From 281ce2cbca28ba7aa5161212c2e9350606b59aba Mon Sep 17 00:00:00 2001
From: Daisuke Oyama <oyama@e.u-tokyo.ac.jp>
Date: Sun, 4 Nov 2018 16:56:29 +0900
Subject: [PATCH] FIX: is_dominated: Return False if num_actions == 1

---
 quantecon/game_theory/normal_form_game.py      |  2 ++
 .../game_theory/tests/test_normal_form_game.py | 18 ++++++++++++++++++
 2 files changed, 20 insertions(+)

diff --git a/quantecon/game_theory/normal_form_game.py b/quantecon/game_theory/normal_form_game.py
index 6df250df6..8feb1b942 100644
--- a/quantecon/game_theory/normal_form_game.py
+++ b/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:]))
 
diff --git a/quantecon/game_theory/tests/test_normal_form_game.py b/quantecon/game_theory/tests/test_normal_form_game.py
index e390757db..bd583ff30 100644
--- a/quantecon/game_theory/tests/test_normal_form_game.py
+++ b/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():