请写一个测试DQN算法收敛性的代码

以下是一个测试DQN算法收敛性的Python代码示例：

import gym
import numpy as np
import tensorflow as tf
from tensorflow.keras.layers import Dense
from tensorflow.keras.models import Sequential
from tensorflow.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 = []
        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 np.random.choice(self.action_size)
        act_values = self.model.predict(state)
        return np.argmax(act_values[0])

    def replay(self, batch_size):
        minibatch = np.random.choice(len(self.memory), batch_size, replace=False)
        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

    def load(self, name):
        self.model.load_weights(name)

    def save(self, name):
        self.model.save_weights(name)

env = gym.make('CartPole-v1')
state_size = env.observation_space.shape[0]
action_size = env.action_space.n
agent = DQNAgent(state_size, action_size)

done = False
batch_size = 32
EPISODES = 1000

for e in range(EPISODES):
    state = env.reset()
    state = np.reshape(state, [1, state_size])
    for time in range(500):
        action = agent.act(state)
        next_state, reward, done, _ = env.step(action)
        reward = reward if not done else -10
        next_state = np.reshape(next_state, [1, state_size])
        agent.remember(state, action, reward, next_state, done)
        state = next_state
        if done:
            print("episode: {}/{}, score: {}, e: {:.2}".format(e, EPISODES, time, agent.epsilon))
            break
    if len(agent.memory) > batch_size:
        agent.replay(batch_size)
    if e % 50 == 0:
        agent.save("dqn.h5")

这个代码使用了OpenAI Gym中的CartPole环境来测试DQN算法的收敛性。在每个episode中，agent会执行一系列动作，直到游戏结束。在每个时间步，agent会根据当前状态选择一个动作，并将其存储到记忆中。当记忆中的样本数量达到一定数量时，agent会从中随机选择一批样本进行训练。训练过程中，agent会根据当前状态和动作的Q值以及下一个状态的最大Q值来计算目标Q值，并使用MSE作为损失函数进行训练。在训练过程中，agent会逐渐降低探索率，以便更好地利用已有的知识。