由于本题需要创建一个具有6个路由器的网络拓扑结构,需要使用第三方库networkx来创建图形结构,并使用numpy来进行数学计算。代码如下:

import networkx as nx
import numpy as np

# 创建图形结构
G = nx.Graph()
G.add_nodes_from([0, 1, 2, 3, 4, 5])
G.add_edges_from([(0, 1), (0, 2), (2, 3), (3, 4), (3, 5)])

# 计算每个节点的邻居和传输时间
neighbors = {}
transfer_time = {}
for node in G.nodes():
    neighbors[node] = list(G.neighbors(node))
    transfer_time[node] = []
    for neighbor in neighbors[node]:
        if (node, neighbor) in G.edges():
            transfer_time[node].append(1)
        else:
            transfer_time[node].append(2)

# 定义Q-learning算法
def q_learning(num_episodes, alpha, gamma, epsilon):
    Q = np.zeros((len(G.nodes()), len(G.nodes()), len(G.nodes())))
    episode_durations = []
    for episode in range(num_episodes):
        current_state = np.random.choice(range(len(G.nodes())))
        duration = 0
        while current_state != 5:
            if np.random.uniform() < epsilon:
                action = np.random.choice(neighbors[current_state])
            else:
                action = np.argmax(Q[current_state])
            next_state = action
            reward = -transfer_time[current_state][next_state]
            Q[current_state][action] += alpha * (reward + gamma * np.max(Q[next_state]) - Q[current_state][action])
            current_state = next_state
            duration += transfer_time[current_state][next_state]
        episode_durations.append(duration)
    return Q, episode_durations

# 运行Q-learning算法并输出结果
Q, episode_durations = q_learning(num_episodes=1000, alpha=0.1, gamma=0.9, epsilon=0.1)
print("平均时延:", np.mean(episode_durations))
print("平均时延随时间的变化:", episode_durations)

其中,Q-learning算法的具体实现如下:

  1. 初始化Q值为0;
  2. 选择起点状态;
  3. 在当前状态下,根据ε-greedy策略选择下一步动作:以ε的概率随机选择一个邻居节点,以1-ε的概率选择当前状态下Q值最大的邻居节点;
  4. 更新Q值:根据当前状态、动作、奖励和下一步状态计算新的Q值,并使用学习率α进行更新;
  5. 更新当前状态为下一步状态;
  6. 重复步骤3-5,直到到达终点状态;
  7. 记录当前episode的持续时间,并重复步骤2-6,直到完成指定数量的episode。

最后,将每个episode的持续时间存储在episode_durations中,并计算平均时延和平均时延随时间的变化


原文地址: http://www.cveoy.top/t/topic/eP6w 著作权归作者所有。请勿转载和采集!

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