视频编码中,用强化学习基于SATD来预测qp值的代码
时间: 2024-03-15 21:47:32 浏览: 242
一种基于SATD的帧内预测算法
强化学习基于SATD来预测qp值的代码需要结合具体的算法和框架来实现,这里给出一个基于Deep Q-Learning算法的伪代码示例:
```python
import numpy as np
import tensorflow as tf
# 定义神经网络模型
class QNetwork(tf.keras.Model):
def __init__(self, state_dim, action_dim):
super(QNetwork, self).__init__()
self.fc1 = tf.keras.layers.Dense(64, activation='relu')
self.fc2 = tf.keras.layers.Dense(32, activation='relu')
self.fc3 = tf.keras.layers.Dense(action_dim, activation=None)
def call(self, state):
x = self.fc1(state)
x = self.fc2(x)
q_values = self.fc3(x)
return q_values
# 定义DQN算法
class DQNAgent:
def __init__(self, state_dim, action_dim, lr=0.001, gamma=0.99, epsilon=1.0, epsilon_min=0.01, epsilon_decay=0.995):
self.state_dim = state_dim
self.action_dim = action_dim
self.lr = lr
self.gamma = gamma
self.epsilon = epsilon
self.epsilon_min = epsilon_min
self.epsilon_decay = epsilon_decay
self.q_network = QNetwork(state_dim, action_dim)
self.target_network = QNetwork(state_dim, action_dim)
self.optimizer = tf.keras.optimizers.Adam(lr=self.lr)
self.loss_fn = tf.keras.losses.MeanSquaredError()
# 选择动作
def act(self, state):
# epsilon-greedy策略
if np.random.rand() <= self.epsilon:
return np.random.randint(self.action_dim)
else:
q_values = self.q_network(state)
return np.argmax(q_values[0])
# 训练网络
def train(self, replay_buffer, batch_size=32):
# 从经验回放池中随机采样一批数据
state_batch, action_batch, reward_batch, next_state_batch, done_batch = replay_buffer.sample(batch_size)
# 计算目标Q值
next_q_values = self.target_network(next_state_batch)
max_next_q_values = tf.reduce_max(next_q_values, axis=-1, keepdims=True)
target_q_values = reward_batch + (1 - done_batch) * self.gamma * max_next_q_values
# 计算当前Q值
with tf.GradientTape() as tape:
q_values = self.q_network(state_batch)
one_hot_actions = tf.one_hot(action_batch, depth=self.action_dim)
current_q_values = tf.reduce_sum(tf.multiply(q_values, one_hot_actions), axis=-1)
# 计算损失
loss = self.loss_fn(target_q_values, current_q_values)
# 计算梯度并更新网络参数
grads = tape.gradient(loss, self.q_network.trainable_variables)
self.optimizer.apply_gradients(zip(grads, self.q_network.trainable_variables))
# 更新探索率
self.epsilon = max(self.epsilon * self.epsilon_decay, self.epsilon_min)
# 更新目标网络参数
def update_target_network(self):
self.target_network.set_weights(self.q_network.get_weights())
# 定义经验回放池
class ReplayBuffer:
def __init__(self, buffer_size):
self.buffer_size = buffer_size
self.buffer = []
# 添加一条经验数据
def add(self, state, action, reward, next_state, done):
experience = (state, action, reward, next_state, done)
if len(self.buffer) >= self.buffer_size:
self.buffer.pop(0)
self.buffer.append(experience)
# 从经验回放池中随机采样一批数据
def sample(self, batch_size):
indices = np.random.randint(0, len(self.buffer), batch_size)
state_batch, action_batch, reward_batch, next_state_batch, done_batch = [], [], [], [], []
for i in indices:
state, action, reward, next_state, done = self.buffer[i]
state_batch.append(state)
action_batch.append(action)
reward_batch.append(reward)
next_state_batch.append(next_state)
done_batch.append(done)
return np.array(state_batch), np.array(action_batch), np.array(reward_batch), np.array(next_state_batch), np.array(done_batch)
# 定义主函数
def main():
# 定义参数
state_dim = 2
action_dim = 1
buffer_size = 10000
batch_size = 32
lr = 0.001
gamma = 0.99
epsilon = 1.0
epsilon_min = 0.01
epsilon_decay = 0.995
max_episodes = 1000
max_steps = 100
update_interval = 10
update_target_interval = 100
# 创建DQN智能体和经验回放池
agent = DQNAgent(state_dim, action_dim, lr, gamma, epsilon, epsilon_min, epsilon_decay)
replay_buffer = ReplayBuffer(buffer_size)
# 训练智能体
for episode in range(max_episodes):
state = np.random.rand(1, state_dim)
for step in range(max_steps):
# 选择动作并执行
action = agent.act(state)
next_state = np.random.rand(1, state_dim)
reward = -1 * abs(next_state[0][0] - next_state[0][1])
done = (step == max_steps - 1)
# 添加经验数据到经验回放池
replay_buffer.add(state, action, reward, next_state, done)
# 训练智能体
if len(replay_buffer.buffer) >= batch_size:
agent.train(replay_buffer, batch_size)
# 更新状态
state = next_state
# 更新目标网络参数
if step % update_target_interval == 0:
agent.update_target_network()
# 打印信息
if step % update_interval == 0:
print("Episode: {}, Step: {}, Epsilon: {:.4f}, Reward: {:.4f}".format(episode, step, agent.epsilon, reward))
if __name__ == "__main__":
main()
```
在这个伪代码示例中,我们使用了一个简单的2维状态空间和1维动作空间,用于模拟视频编码中的SATD和QP值。具体来说,我们在每个状态中随机生成两个数作为SATD和QP值,并根据它们的差值来计算奖励。在训练过程中,我们使用了一个基于经验回放池的DQN算法来学习最优的QP值预测策略。在每个训练步骤中,我们随机选择一个动作并执行,然后将经验数据添加到经验回放池中。当经验回放池中的数据达到一定数量时,我们从中随机采样一批数据进行训练,并使用梯度下降算法来更新网络参数。同时,我们还定期更新目标网络参数,以提高算法的稳定性。在训练过程中,我们还使用了一个探索策略来平衡探索和利用,从而避免陷入局部最优解。
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