本文作者：hhh5460
本文地址：https://www.cnblogs.com/hhh5460/p/10143579.html
感谢pengdali，本文的 class Maze 参考了他的博客，地址：https://blog.csdn.net/pengdali/article/details/79369966
0.问题情境
一个6*6的迷宫，左上角入口，右下角出口。红色矩形为玩家，黑色矩形为陷阱，黄色矩形为元宝。如图
1.问题分析
将二维问题转化为一维问题，并解决之。
状态集：[0,1,..,35]，0~35，共36个。
动作集：['u', 'd', 'l', 'r']，上下左右，共4个。
奖励集：[0,-10,0,0,...,10]，每个位置一个奖励值，共36个。其中空白位置0，陷阱-10，元宝3，出口10（随便）
那么，接下来需要从上三个集合中选择相应的元素或子集，用一维的方式比二维的方式更简便。其方法与前面的例子是类似的，只需要改变首末两行、两列的值即可！这里不细说了。
2.完整代码
import pandas as pd
import random
import time
import pickle
import pathlib
import os
import tkinter as tk '''
6*6 的迷宫：
-------------------------------------------
| 入口 | 陷阱 | | | | |
-------------------------------------------
| | 陷阱 | | | 陷阱 | |
-------------------------------------------
| | 陷阱 | | 陷阱 | | |
-------------------------------------------
| | 陷阱 | | 陷阱 | | |
-------------------------------------------
| | 陷阱 | | 陷阱 | 元宝 | |
-------------------------------------------
| | | | 陷阱 | | 出口 |
------------------------------------------- 作者：hhh5460
时间：20181219
地点：Tai Zi Miao
''' class Maze(tk.Tk):
'''环境类（GUI）'''
UNIT = 40 # pixels
MAZE_H = 6 # grid height
MAZE_W = 6 # grid width def __init__(self):
'''初始化'''
super().__init__()
self.title('迷宫')
h = self.MAZE_H * self.UNIT
w = self.MAZE_W * self.UNIT
self.geometry('{0}x{1}'.format(h, w)) #窗口大小
self.canvas = tk.Canvas(self, bg='white', height=h, width=w)
# 画网格
for c in range(0, w, self.UNIT):
self.canvas.create_line(c, 0, c, h)
for r in range(0, h, self.UNIT):
self.canvas.create_line(0, r, w, r)
# 画陷阱
self._draw_rect(1, 0, 'black')
self._draw_rect(1, 1, 'black')
self._draw_rect(1, 2, 'black')
self._draw_rect(1, 3, 'black')
self._draw_rect(1, 4, 'black')
self._draw_rect(3, 2, 'black')
self._draw_rect(3, 3, 'black')
self._draw_rect(3, 4, 'black')
self._draw_rect(3, 5, 'black')
self._draw_rect(4, 1, 'black')
# 画奖励
self._draw_rect(4, 4, 'yellow')
# 画玩家(保存!!)
self.rect = self._draw_rect(0, 0, 'red')
self.canvas.pack() # 显示画作！ def _draw_rect(self, x, y, color):
'''画矩形， x,y表示横,竖第几个格子'''
padding = 5 # 内边距5px，参见CSS
coor = [self.UNIT * x + padding, self.UNIT * y + padding, self.UNIT * (x+1) - padding, self.UNIT * (y+1) - padding]
return self.canvas.create_rectangle(*coor, fill = color) def move_to(self, state, delay=0.01):
'''玩家移动到新位置，根据传入的状态'''
coor_old = self.canvas.coords(self.rect) # 形如[5.0, 5.0, 35.0, 35.0]（第一个格子左上、右下坐标）
x, y = state % 6, state // 6 #横竖第几个格子
padding = 5 # 内边距5px，参见CSS
coor_new = [self.UNIT * x + padding, self.UNIT * y + padding, self.UNIT * (x+1) - padding, self.UNIT * (y+1) - padding]
dx_pixels, dy_pixels = coor_new[0] - coor_old[0], coor_new[1] - coor_old[1] # 左上角顶点坐标之差
self.canvas.move(self.rect, dx_pixels, dy_pixels)
self.update() # tkinter内置的update!
time.sleep(delay) class Agent(object):
'''个体类'''
def __init__(self, alpha=0.1, gamma=0.9):
'''初始化'''
self.states = range(36) # 状态集。0~35 共36个状态
self.actions = list('udlr') # 动作集。上下左右 4个动作
self.rewards = [0,-10,0, 0, 0, 0,
0,-10,0, 0,-10, 0,
0,-10,0,-10, 0, 0,
0,-10,0,-10, 0, 0,
0,-10,0,-10, 3, 0,
0, 0,0,-10, 0,10,] # 奖励集。出口奖励10，陷阱奖励-10，元宝奖励5
self.hell_states = [1,7,13,19,25,15,31,37,43,10] # 陷阱位置 self.alpha = alpha
self.gamma = gamma self.q_table = pd.DataFrame(data=[[0 for _ in self.actions] for _ in self.states],
index=self.states,
columns=self.actions) def save_policy(self):
'''保存Q table'''
with open('q_table.pickle', 'wb') as f:
# Pickle the 'data' dictionary using the highest protocol available.
pickle.dump(self.q_table, f, pickle.HIGHEST_PROTOCOL) def load_policy(self):
'''导入Q table'''
with open('q_table.pickle', 'rb') as f:
self.q_table = pickle.load(f) def choose_action(self, state, epsilon=0.8):
'''选择相应的动作。根据当前状态，随机或贪婪，按照参数epsilon'''
#if (random.uniform(0,1) > epsilon) or ((self.q_table.ix[state] == 0).all()): # 探索
if random.uniform(0,1) > epsilon: # 探索
action = random.choice(self.get_valid_actions(state))
else:
#action = self.q_table.ix[state].idxmax() # 利用 当有多个最大值时，会锁死第一个！
#action = self.q_table.ix[state].filter(items=self.get_valid_actions(state)).idxmax() # 重大改进！然鹅与上面一样
s = self.q_table.ix[state].filter(items=self.get_valid_actions(state))
action = random.choice(s[s==s.max()].index) # 从可能有多个的最大值里面随机选择一个！
return action def get_q_values(self, state):
'''取给定状态state的所有Q value'''
q_values = self.q_table.ix[state, self.get_valid_actions(state)]
return q_values def update_q_value(self, state, action, next_state_reward, next_state_q_values):
'''更新Q value，根据贝尔曼方程'''
self.q_table.ix[state, action] += self.alpha * (next_state_reward + self.gamma * next_state_q_values.max() - self.q_table.ix[state, action]) def get_valid_actions(self, state):
'''取当前状态下所有的合法动作'''
valid_actions = set(self.actions)
if state % 6 == 5: # 最后一列，则
valid_actions -= set(['r']) # 无向右的动作
if state % 6 == 0: # 最前一列，则
valid_actions -= set(['l']) # 无向左
if state // 6 == 5: # 最后一行，则
valid_actions -= set(['d']) # 无向下
if state // 6 == 0: # 最前一行，则
valid_actions -= set(['u']) # 无向上
return list(valid_actions) def get_next_state(self, state, action):
'''对状态执行动作后，得到下一状态'''
#u,d,l,r,n = -6,+6,-1,+1,0
if state % 6 != 5 and action == 'r': # 除最后一列，皆可向右(+1)
next_state = state + 1
elif state % 6 != 0 and action == 'l': # 除最前一列，皆可向左(-1)
next_state = state - 1
elif state // 6 != 5 and action == 'd': # 除最后一行，皆可向下(+2)
next_state = state + 6
elif state // 6 != 0 and action == 'u': # 除最前一行，皆可向上(-2)
next_state = state - 6
else:
next_state = state
return next_state def learn(self, env=None, episode=1000, epsilon=0.8):
'''q-learning算法'''
print('Agent is learning...')
for i in range(episode):
current_state = self.states[0] if env is not None: # 若提供了环境，则重置之！
env.move_to(current_state) while current_state != self.states[-1]:
current_action = self.choose_action(current_state, epsilon) # 按一定概率，随机或贪婪地选择
next_state = self.get_next_state(current_state, current_action)
next_state_reward = self.rewards[next_state]
next_state_q_values = self.get_q_values(next_state)
self.update_q_value(current_state, current_action, next_state_reward, next_state_q_values)
current_state = next_state #if next_state not in self.hell_states: # 非陷阱，则往前；否则待在原位
# current_state = next_state if env is not None: # 若提供了环境，则更新之！
env.move_to(current_state)
print(i)
print('\nok') def test(self):
'''测试agent是否已具有智能'''
count = 0
current_state = self.states[0]
while current_state != self.states[-1]:
current_action = self.choose_action(current_state, 1.) # 1., 贪婪
next_state = self.get_next_state(current_state, current_action)
current_state = next_state
count += 1 if count > 36: # 没有在36步之内走出迷宫，则
return False # 无智能 return True # 有智能 def play(self, env=None, delay=0.5):
'''玩游戏，使用策略'''
assert env != None, 'Env must be not None!' if not self.test(): # 若尚无智能，则
if pathlib.Path("q_table.pickle").exists():
self.load_policy()
else:
print("I need to learn before playing this game.")
self.learn(env, episode=1000, epsilon=0.5)
self.save_policy() print('Agent is playing...')
current_state = self.states[0]
env.move_to(current_state, delay)
while current_state != self.states[-1]:
current_action = self.choose_action(current_state, 1.) # 1., 贪婪
next_state = self.get_next_state(current_state, current_action)
current_state = next_state
env.move_to(current_state, delay)
print('\nCongratulations, Agent got it!') if __name__ == '__main__':
env = Maze() # 环境
agent = Agent() # 个体（智能体）
#agent.learn(env, episode=1000, epsilon=0.6) # 先学习
#agent.save_policy()
#agent.load_policy()
agent.play(env) # 再玩耍 #env.after(0, agent.learn, env, 1000, 0.8) # 先学
#env.after(0, agent.save_policy) # 保存所学
#env.after(0, agent.load_policy) # 导入所学
#env.after(0, agent.play, env) # 再玩
env.mainloop()
重大改进：Agent.choose_action()。之前贪婪的时候直接用idxmax()，会锁死第一个最大值对应的方向！