def TrainOneRound(self, afterstate_num, alpha=.1):
""" Q learning following Sutton and Barto 6.5
Input:
afterstate: the afterstate of target_policy to start trainng with
Note that the opponent makes a move first, then the target policy.
"""
afterstate = State(from_base10=afterstate_num)
while not afterstate.is_terminal():
beforestate_num = self.random_policy.move(
afterstate.get_num()) # opponent makes a move
beforestate = State(from_base10=beforestate_num)
if beforestate.is_terminal():
r = beforestate.get_reward()
self.target_policy.v_dict[afterstate.get_num()] += alpha * (
r - self.target_policy.v_dict[afterstate.get_num()])
break
else:
s_primes = beforestate.legal_afterstates()
candidates = []
for s_prime in s_primes:
r = State(from_base10=s_prime).get_reward()
q = self.target_policy.v_dict[s_prime]
candidates.append(r + q)
if beforestate.turn == 1:
self.target_policy.v_dict[
afterstate.get_num()] += alpha * (
max(candidates) -
self.target_policy.v_dict[afterstate.get_num()])
else:
self.target_policy.v_dict[
afterstate.get_num()] += alpha * (
min(candidates) -
self.target_policy.v_dict[afterstate.get_num()])
afterstate_num = self.random_policy.move(beforestate_num)
afterstate = State(from_base10=afterstate_num)
def test_legal_afterstates():
# full board, no legal afterstate
state = State(board=[[2, 2, 2], [1, 1, 1], [1, 2, 2]], turn=1)
assert not state.legal_afterstates()
# one legal afterstate
state = State(board=[[2, 2, 2], [1, 1, 1], [1, 0, 2]], turn=1)
assert state.legal_afterstates() == [
State([[2, 2, 2], [1, 1, 1], [1, 1, 2]], turn=2).get_num()
]
# 3 legal afterstates
state = State(board=[[2, 2, 2], [1, 1, 1], [0, 0, 0]], turn=2)
temp = state.legal_afterstates()
assert len(temp) == 3
num1 = State(board=[[2, 2, 2], [1, 1, 1], [2, 0, 0]]).get_num()
num2 = State(board=[[2, 2, 2], [1, 1, 1], [0, 2, 0]]).get_num()
num3 = State(board=[[2, 2, 2], [1, 1, 1], [0, 0, 2]]).get_num()
assert set(temp) == set([num1, num2, num3])
def ValueIteration(self, theta=0.01):
t = time.time()
while True:
delta = 0
for num in range(int('1' + '0' * 9, 3), int('2' * 10, 3) + 1):
v = self.policy_1.v_dict[num]
state = State(from_base10=num)
if state.is_terminal():
self.policy_1.v_dict[num] = state.get_reward()
else:
opponent_afterstate = State(
from_base10=self.policy_2.move_dict[num])
if opponent_afterstate.is_terminal():
self.policy_1.v_dict[
num] = opponent_afterstate.get_reward()
else:
s_prime_choices = opponent_afterstate.legal_afterstates(
)
if state.turn == 2:
vi_update = max([
self.policy_1.v_dict[x]
for x in s_prime_choices
])
else:
vi_update = min([
self.policy_1.v_dict[x]
for x in s_prime_choices
])
self.policy_1.v_dict[num] = vi_update
delta = max(delta, np.abs(v - self.policy_1.v_dict[num]))
self.i_epoch += 1
if delta < theta:
print('Value function has converged!')
print("Trained %i epochs so far." % self.i_epoch)
self.policy_ever_changed = self.policy_1.be_greedy()
pickle.dump((self.policy_1, self.i_epoch),
open(self.write_path, "wb"))
break
if time.time() - t > 10:
t = time.time()
print("Trained %i epochs so far." % self.i_epoch)
self.policy_ever_changed = self.policy_1.be_greedy()
pickle.dump((self.policy_1, self.i_epoch),
open(self.write_path, "wb"))
def PolicyImprovement(self):
""" Policy Improvement following Sutton Barto 4.3
Against rush opponent, with afterstates
"""
self.policy_stable = True
for num in range(int('1' + '0' * 9, 3), int('2' * 10, 3) + 1):
state = State(from_base10=num)
if not state.is_terminal():
old_action_num = self.policy_1.move_dict[num]
# get the best afterstates
afterstate_nums = state.legal_afterstates()
afterstate_values = [
self.policy_1.v_dict[x] for x in afterstate_nums
]
best = np.argmax(
afterstate_values) if state.turn == 1 else np.argmin(
afterstate_values)
self.policy_1.move_dict[num] = afterstate_nums[best]
if old_action_num != self.policy_1.move_dict[num]:
self.policy_stable = False
self.policy_ever_changed = True
