在keras.models Jupyter Python中使用model.fit()方法进行深度Q学习寻宝游戏的步骤如下:
import numpy as np
from keras.models import Sequential
from keras.layers import Dense
from keras.optimizers import Adam
model = Sequential()
model.add(Dense(24, input_dim=state_size, activation='relu'))
model.add(Dense(24, activation='relu'))
model.add(Dense(action_size, activation='linear'))
model.compile(loss='mse', optimizer=Adam(lr=learning_rate))
在这个例子中,我们使用了一个具有两个隐藏层的全连接神经网络模型。输入层的维度取决于状态空间的大小,输出层的维度取决于动作空间的大小。
class ReplayBuffer():
def __init__(self, buffer_size):
self.buffer = []
self.buffer_size = buffer_size
def add(self, experience):
if len(self.buffer) + len(experience) >= self.buffer_size:
self.buffer[0:(len(experience) + len(self.buffer)) - self.buffer_size] = []
self.buffer.extend(experience)
def sample(self, batch_size):
return np.reshape(np.array(random.sample(self.buffer, batch_size)), [batch_size, 5])
经验回放缓冲区用于存储智能体的经验,以便在训练过程中进行随机采样。
def epsilon_greedy_policy(state, epsilon):
if np.random.rand() <= epsilon:
return random.randrange(action_size)
else:
q_values = model.predict(state)
return np.argmax(q_values[0])
ε-greedy策略函数根据当前状态选择动作。以ε的概率选择随机动作,以1-ε的概率选择具有最高Q值的动作。
def train_model():
for episode in range(num_episodes):
state = env.reset()
state = np.reshape(state, [1, state_size])
done = False
time = 0
while not done:
action = epsilon_greedy_policy(state, epsilon)
next_state, reward, done, _ = env.step(action)
next_state = np.reshape(next_state, [1, state_size])
experience = (state, action, reward, next_state, done)
replay_buffer.add(experience)
state = next_state
time += 1
if time > start_learning_time:
minibatch = replay_buffer.sample(batch_size)
states = np.array([experience[0] for experience in minibatch])
actions = np.array([experience[1] for experience in minibatch])
rewards = np.array([experience[2] for experience in minibatch])
next_states = np.array([experience[3] for experience in minibatch])
dones = np.array([experience[4] for experience in minibatch])
q_values = model.predict(states)
next_q_values = model.predict(next_states)
max_next_q_values = np.max(next_q_values, axis=1)
target_q_values = rewards + gamma * (1 - dones) * max_next_q_values
q_values[np.arange(batch_size), actions] = target_q_values
model.fit(states, q_values, epochs=1, verbose=0)
在训练函数中,我们使用ε-greedy策略选择动作,并将经验存储到经验回放缓冲区中。然后,我们从经验回放缓冲区中随机采样一批经验,并使用目标Q值更新当前Q值。最后,我们使用model.fit()方法进行一次训练。
这是一个简单的深度Q学习寻宝游戏的训练过程。在实际应用中,您可能需要根据具体问题进行适当的调整和优化。
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