def _add_noise(noise, s1, s2):
r = random.random()
if r < noise:
s1 = flip_action(s1)
r = random.random()
if r < noise:
s2 = flip_action(s2)
return s1, s2
def strategy(self, opponent):
# Random first move
if not self.history:
return random_choice()
# Act opposite of opponent otherwise
return flip_action(opponent.history[-1])
def strategy(self, opponent):
# Random first move
if not self.history:
return random_choice();
# Act opposite of opponent otherwise
return flip_action(opponent.history[-1])
def strategy(self, opponent):
# Defect on the first move
if not opponent.history:
return D
# Am I TFT?
if self.is_TFT:
return D if opponent.history[-1:] == [D] else C
else:
# Did opponent defect?
if opponent.history[-1] == D:
self.is_TFT = True
return C
if len(self.history) in [1, 2]:
return C
# Alternate C and D
return flip_action(self.history[-1])
def strategy(self, opponent):
# Defect on the first move
if not opponent.history:
return D
# Am I TFT?
if self.is_TFT:
return D if opponent.history[-1:] == [D] else C
else:
# Did opponent defect?
if opponent.history[-1] == D:
self.is_TFT = True
return C
if len(self.history) in [1, 2]:
return C
# Alternate C and D
return flip_action(self.history[-1])
def strategy(self, opponent):
round_number = len(self.history) + 1
# According to internet sources, the original implementation defected
# on the first two moves. Otherwise it wins (if this code is removed
# and the comment restored.
# http://www.sci.brooklyn.cuny.edu/~sklar/teaching/f05/alife/notes/azhar-ipd-Oct19th.pdf
if self.revised:
if round_number == 1:
self.move = C
return self.move
elif not self.revised:
if round_number <= 2:
self.move = D
return self.move
# Update various counts
if round_number > 2:
if self.history[-1] == D:
if opponent.history[-1] == C:
self.nice2 += 1
self.total_D += 1
self.bad = float(self.nice2) / self.total_D
else:
if opponent.history[-1] == C:
self.nice1 += 1
self.total_C += 1
self.good = float(self.nice1) / self.total_C
# Make a decision based on the accrued counts
c = 6.0 * self.good - 8.0 * self.bad - 2
alt = 4.0 * self.good - 5.0 * self.bad - 1
if (c >= 0 and c >= alt):
self.move = C
elif (c >= 0 and c < alt) or (alt >= 0):
self.move = flip_action(self.move)
else:
self.move = D
return self.move
def strategy(self, opponent):
round_number = len(self.history) + 1
# According to internet sources, the original implementation defected
# on the first two moves. Otherwise it wins (if this code is removed
# and the comment restored.
# http://www.sci.brooklyn.cuny.edu/~sklar/teaching/f05/alife/notes/azhar-ipd-Oct19th.pdf
if self.revised:
if round_number == 1:
self.move = C
return self.move
elif not self.revised:
if round_number <= 2:
self.move = D
return self.move
# Update various counts
if round_number > 2:
if self.history[-1] == D:
if opponent.history[-1] == C:
self.nice2 += 1
self.total_D += 1
self.bad = float(self.nice2) / self.total_D
else:
if opponent.history[-1] == C:
self.nice1 += 1
self.total_C += 1
self.good = float(self.nice1) / self.total_C
# Make a decision based on the accrued counts
c = 6.0 * self.good - 8.0 * self.bad - 2
alt = 4.0 * self.good - 5.0 * self.bad - 1
if (c >= 0 and c >= alt):
self.move = C
elif (c >= 0 and c < alt) or (alt >= 0):
self.move = flip_action(self.move)
else:
self.move = D
return self.move
def test_flip_action(self):
self.assertEqual(flip_action(D), C)
self.assertEqual(flip_action(C), D)
def test_flip_action(self):
self.assertEqual(flip_action(D), C)
self.assertEqual(flip_action(C), D)
with self.assertRaises(ValueError):
flip_action('R')
def test_flip_action(self):
self.assertEqual(flip_action(Actions.D), Actions.C)
self.assertEqual(flip_action(Actions.C), Actions.D)
with self.assertRaises(ValueError):
flip_action('R')
