Test lemke howson exceptions

quantecon/game_theory/lemke_howson.py

@@ -5,6 +5,7 @@
 Lemke-Howson algorithm.
 
 """
+import numbers
 import numpy as np
 from numba import jit
 from .utilities import NashResult
@@ -128,11 +129,14 @@ def lemke_howson(g, init_pivot=0, max_iter=10**6, capping=None,
  nums_actions = g.nums_actions
  total_num = sum(nums_actions)
 
+ msg = '`init_pivot` must be an integer k' + \
+ 'such that 0 <= k < {0}'.format(total_num)
+
+ if not isinstance(init_pivot, numbers.Integral):
+ raise TypeError(msg)
+
  if not (0 <= init_pivot < total_num):
- raise ValueError(
- '`init_pivot` must be an integer k such that 0 <= k < {0}'
- .format(total_num)
- )
+ raise ValueError(msg)
 
  if capping is None:
  capping = max_iter

quantecon/game_theory/tests/test_lemke_howson.py

@@ -6,7 +6,7 @@
 """
 import numpy as np
 from numpy.testing import assert_allclose
-from nose.tools import eq_
+from nose.tools import eq_, raises
 from quantecon.game_theory import Player, NormalFormGame, lemke_howson
 
 
@@ -110,6 +110,32 @@ def test_lemke_howson_capping():
  eq_(res.init, init_pivot-1)
 
 
+@raises(TypeError)
+def test_lemke_howson_invalid_g():
+ bimatrix = [[(3, 3), (3, 2)],
+ [(2, 2), (5, 6)],
+ [(0, 3), (6, 1)]]
+ lemke_howson(bimatrix)
+
+
+@raises(ValueError)
+def test_lemke_howson_invalid_init_pivot_integer():
+ bimatrix = [[(3, 3), (3, 2)],
+ [(2, 2), (5, 6)],
+ [(0, 3), (6, 1)]]
+ g = NormalFormGame(bimatrix)
+ lemke_howson(g, -1)
+
+
+@raises(TypeError)
+def test_lemke_howson_invalid_init_pivot_float():
+ bimatrix = [[(3, 3), (3, 2)],
+ [(2, 2), (5, 6)],
+ [(0, 3), (6, 1)]]
+ g = NormalFormGame(bimatrix)
+ lemke_howson(g, 1.0)
+
+
 if __name__ == '__main__':
  import sys
  import nose