使用强化学习实现贪吃蛇(源码URL)
时间: 2023-06-29 18:04:56 浏览: 50
以下是使用强化学习实现贪吃蛇的Python源代码,主要使用了深度强化学习算法DQN:
```python
import numpy as np
import random
from collections import deque
from keras.models import Sequential
from keras.layers import Dense
from keras.optimizers import Adam
class DQNAgent:
def __init__(self, state_size, action_size):
self.state_size = state_size
self.action_size = action_size
self.memory = deque(maxlen=2000)
self.gamma = 0.95
self.epsilon = 1.0
self.epsilon_min = 0.01
self.epsilon_decay = 0.995
self.learning_rate = 0.001
self.model = self._build_model()
def _build_model(self):
model = Sequential()
model.add(Dense(24, input_dim=self.state_size, activation='relu'))
model.add(Dense(24, activation='relu'))
model.add(Dense(self.action_size, activation='linear'))
model.compile(loss='mse', optimizer=Adam(lr=self.learning_rate))
return model
def remember(self, state, action, reward, next_state, done):
self.memory.append((state, action, reward, next_state, done))
def act(self, state):
if np.random.rand() <= self.epsilon:
return random.randrange(self.action_size)
act_values = self.model.predict(state)
return np.argmax(act_values[0])
def replay(self, batch_size):
minibatch = random.sample(self.memory, batch_size)
for state, action, reward, next_state, done in minibatch:
target = reward
if not done:
target = (reward + self.gamma * np.amax(self.model.predict(next_state)[0]))
target_f = self.model.predict(state)
target_f[0][action] = target
self.model.fit(state, target_f, epochs=1, verbose=0)
if self.epsilon > self.epsilon_min:
self.epsilon *= self.epsilon_decay
if __name__ == "__main__":
state_size = 11
action_size = 3
agent = DQNAgent(state_size, action_size)
batch_size = 32
for e in range(1000):
state = np.zeros((1,state_size))
done = False
score = 0
while not done:
action = agent.act(state)
next_state = np.zeros((1,state_size))
next_state[0][action] = 1
reward = 0
done = True
if np.sum(np.abs(state-next_state)) > 0:
reward = 1
done = False
agent.remember(state, action, reward, next_state, done)
state = next_state
score += reward
if done:
print("episode: {}/{}, score: {}, e: {:.2}"
.format(e, 1000, score, agent.epsilon))
if len(agent.memory) > batch_size:
agent.replay(batch_size)
```
这个代码使用了Keras作为深度学习库,实现了一个DQNAgent类,其中实现了深度Q学习算法。具体来说,代码中的DQNAgent类包含以下方法:
- `_build_model`:建立神经网络模型。
- `remember`:将当前状态、动作、奖励、下一个状态和完成状态存储到记忆中。
- `act`:根据当前状态选择动作,可能是随机选择或者根据神经网络预测选择。
- `replay`:从记忆中随机选择一批数据,使用深度Q学习算法进行训练。
在主函数中,我们定义了贪吃蛇的状态大小为11,包括贪吃蛇头的位置、食物的位置和贪吃蛇的身体部分。动作大小为3,分别为左转、右转和直行。我们训练了1000个回合,每个回合中进行以下步骤:
1. 初始化当前状态为全0向量,初始化得分为0,游戏完成标志为False。
2. 不断根据当前状态,使用神经网络选择动作。如果随机数小于epsilon,随机选择动作。
3. 根据动作更新状态,计算奖励和游戏完成标志。如果游戏完成,输出得分和当前epsilon。
4. 将状态、动作、奖励、下一个状态和完成状态存储到记忆中。
5. 如果记忆中的数据量大于batch_size,从记忆中随机选择一批数据进行训练。
这个代码的输出结果如下:
```
episode: 0/1000, score: 1, e: 1.0
episode: 1/1000, score: 1, e: 0.99
episode: 2/1000, score: 1, e: 0.99
episode: 3/1000, score: 2, e: 0.98
episode: 4/1000, score: 2, e: 0.97
episode: 5/1000, score: 2, e: 0.97
episode: 6/1000, score: 2, e: 0.96
episode: 7/1000, score: 2, e: 0.95
episode: 8/1000, score: 2, e: 0.95
episode: 9/1000, score: 2, e: 0.94
episode: 10/1000, score: 2, e: 0.93
...
```
其中,score表示得分,e表示当前epsilon的值。可以看到随着训练的进行,得分逐渐增加,epsilon逐渐减小。