def Q_train(alpha, gamma, epsilon, max_iterations):
w = np.zeros((SS,act_set)) # Initialize
b = 0 # Initialize
Rewards = []
for noe in range(episodes):
state = Car.reset()
r = 0 # Initialize reward
done = False
for m in range(max_iterations):
if done == True:
break
q_vals = weight(state, w, b)
a = Action_select(q_vals, epsilon)
Q = q_vals[a]
Sprime, reward, done = Car.step(a)
'''Computing q_pi (s,a)'''
Qprime = weight(Sprime, w, b)
Q_next = max(Qprime)
'''Gradient Update'''
grad = alpha * (Q - (reward + gamma*Q_next))
for j in state.keys():
w[j][a] = w[j][a] - grad * state[j]
b = b - grad
state = Sprime
r += reward
## Rendering ##
'''Executed to see improvements after every 1000 episodes else it slows the overall execution'''
if noe%1000 == 0:
MountainCar.render(Car)
#env
Rewards.append(r)
MountainCar.close(Car)
return w, b, Rewards
def main():
(program, mode, weight_out, returns_out, episodes, max_iterations, epsilon,
gamma, alpha) = sys.argv
epsilon, gamma, alpha, episodes, max_iterations = float(epsilon), float(
gamma), float(alpha), int(episodes), int(max_iterations)
# Output files
w_out = open(weight_out, 'w')
r_out = open(returns_out, 'w')
# Initialize Mountain Car
car = MountainCar(mode=mode)
actions, num_actions = (0, 1, 2), 3
# Weights: <dim(S)> by <num_actions> matrix
w = np.zeros((car.state_space, num_actions))
bias = 0
# Represent state as numpy array
def state_rep(state_dict, mode):
if mode == "raw":
state = np.asarray(list(state_dict.values()))
elif mode == "tile":
state = np.zeros(2048)
for key in state_dict:
state[key] = 1
return state
# Do actions
for i in range(episodes):
# Initialize
num_iters = 0
total_rewards = 0
# Raw dictionary
state_dict = car.reset()
# Convert to numpy array
state = state_rep(state_dict, mode)
while num_iters < max_iterations:
num_iters += 1
# E greedy
action = getAction(state, actions, epsilon, w, bias)
# Observe sample
(next_state_dict, reward, done) = car.step(action)
# Add current reward
total_rewards += reward
# Next state, get best action for next state
next_state = state_rep(next_state_dict, mode)
next_best_action = getBestAction(next_state, actions, w, bias)
next_state_best_Q = QValue(next_state, next_best_action, w, bias)
# Sample
sample = reward + (gamma * next_state_best_Q)
diff = QValue(state, action, w, bias) - sample
# Update weights
w[:, action] = w[:, action] - alpha * diff * state
bias = bias - alpha * diff * 1
# Break if done
if not done:
state = next_state
else:
break
# Print rewards
r_out.write(str(total_rewards) + "\n")
# Print weight outputs
w_out.write(str(bias) + '\n')
for row in w:
for elem in row:
w_out.write(str(elem) + '\n')
# Close
car.close()
w_out.close()
r_out.close()
class qlearning(object):
def __init__(self, mode, epsilon, gamma, learning_rate):
self.epsilon = epsilon
self.gamma = gamma
self.lr = learning_rate
self.mode = mode
self.env = MountainCar(mode)
self.state_space = self.env.state_space
self.action_space = 3
self.W = np.zeros((self.state_space, self.action_space))
self.b = 0
# given the current state and action, approximate thee action value (q_s)
def linear_approx(self, state):
#return np.dot(state.T, self.W).T + self.b
return state.dot(self.W) + self.b
# choose an action based on epsilon-greedy method
def select_action(self, state):
if np.random.rand() < self.epsilon:
# selects uniformly at random from one of the 3 actions (0, 1, 2) with probability ε
return np.random.randint(0, self.action_space)
else:
# selects the optimal action with probability 1 − ε
# In case of multiple maximum values, return the first one
return np.argmax(self.linear_approx(state))
def transfer_state(self, state):
if self.mode == "raw":
return np.fromiter(state.values(), dtype=float)
elif self.mode == "tile":
idx = sorted(state.keys())
trans_state = np.zeros((self.state_space))
trans_state[idx] = 1
return trans_state
else:
print("Error mode.")
return
def run(self, weight_out, returns_out, episodes, max_iterations):
with open(returns_out, 'w') as f_returns:
# perform training
for episode in range(episodes):
rewards = 0
state = self.transfer_state(self.env.reset())
if Debug:
print("episode " + str(episode) + " init state: ", end="")
print(state)
for i in range(max_iterations):
# call step
action = self.select_action(state)
next_state, reward, done = self.env.step(action)
next_state = self.transfer_state(next_state)
if Debug and i % 100 == 0:
print("episode " + str(episode) + " iter " + str(i) +
", action: " + str(action) + " next state: ",
end="")
print(next_state)
# update w_a
delta = state
cur_q = self.linear_approx(state)
next_q = self.linear_approx(next_state)
self.W[:, action] = self.W[:, action] - self.lr * (
cur_q[action] -
(reward + self.gamma * np.max(next_q))) * delta
# update bias
self.b = self.b - self.lr * (
cur_q[action] - (reward + self.gamma * np.max(next_q)))
state = next_state
rewards += reward
if done:
break
f_returns.write(str(rewards) + "\n")
if Debug:
print("[episode ", episode + 1, "] total rewards: ",
rewards)
with open(weight_out, 'w') as f_weight:
f_weight.write(str(self.b) + "\n")
# write the values of weights in row major order
for i in range(self.W.shape[0]):
for j in range(self.W.shape[1]):
f_weight.write(str(self.W[i][j]) + "\n")
# visualization
# self.env.render()
def close(self):
self.env.close()
