【深入浅出强化学习-原理入门】1 基于gym的MDP(作业）

题目：基于gym构建如下迷宫世界：
在这里插入图片描述
全部代码：

maze_mdp.py

python">import logging #日志模块
import numpy
import random
from gym import spaces
import gym

logging = logging.getLogger(__name__)


# Set this in SOME subclasses
class MazeEnv(gym.Env):
    metadata = {
        'render.modes':['human','rgb_array'],
        'video.frames_per_second':2
    }
    def _seed(self, seed=None):
        self.np_random, seed = seeding.np_random(seed)
        return [seed]


    def __init__(self):
        # 状态空间
        self.states = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18]
        # 设置机器人的位置，机器人的位置根据所处状态不同位置也不同。
        # 事先计算出每个状态点机器人位置的中心坐标，并存储到两个向量中，在类初始化中给出
        self.x = [125, 175, 225, 325, 125, 175, 225, 325, 225, 275, 325, 125, 175, 225, 275, 325, 125, 175]
        self.y = [325, 325, 325, 325, 275, 275, 275, 275, 225, 225, 225, 175, 175, 175, 175, 175, 125, 125]
        self.terminate_states = dict() #终止状态为字典格式
        self.terminate_states[11] = 1

        # 动作空间
        self.actions = ['n','e','s','w']

        # 回报函数
        self.rewards = dict(); #回报的数据结构为字典
        self.rewards['18_s'] = 20.0
        self.rewards['10_e'] = 20.0
        self.rewards['16_n'] = 20.0

        # 状态转移概率
        self.t = dict();
        self.t['1_e'] = 2
        self.t['1_s'] = 5
        self.t['2_w'] = 1
        self.t['2_e'] = 3
        self.t['2_s'] = 6
        self.t['3_w'] = 2
        self.t['3_s'] = 7
        self.t['4_s'] = 8
        self.t['5_e'] = 6
        self.t['5_n'] = 1
        self.t['6_w'] = 5
        self.t['6_e'] = 7
        self.t['6_n'] = 2
        self.t['7_w'] = 6
        self.t['7_s'] = 9
        self.t['7_n'] = 3
        self.t['8_s'] = 11
        self.t['8_n'] = 4
        self.t['9_e'] = 10
        self.t['9_s'] = 14
        self.t['9_n'] = 7
        self.t['10_w'] = 9
        self.t['10_e'] = 11
        self.t['10_s'] = 15
        self.t['11_w'] = 10
        self.t['11_s'] = 16
        self.t['11_n'] = 8
        self.t['12_e'] = 13
        self.t['12_s'] = 17
        self.t['13_w'] = 12
        self.t['13_e'] = 14
        self.t['13_s'] = 18
        self.t['14_w'] = 13
        self.t['14_e'] = 15
        self.t['14_n'] = 9
        self.t['15_w'] = 14
        self.t['15_e'] = 16
        self.t['15_n'] = 10
        self.t['16_w'] = 15
        self.t['16_n'] = 11
        self.t['17_e'] = 18
        self.t['17_n'] = 12
        self.t['18_w'] = 17
        self.t['18_n'] = 13

        #折扣因子
        self.gamma = 0.8
        self.viewer = None
        self.state = None

    def getTerminal(self):
        return self.terminate_states

    def getGamma(self):
        return self.gamma

    def getStates(self):
        return self.states

    def getAction(self):
        return self.actions

    def getTerminate_states(self):
        return self.terminate_states

    def setAction(self,s):
        self.state = s

    # step()函数输入是动作，
    # 输出是下一时刻的动作、回报、是否终止、调试信息
    # 没有的用{}表示
    def _step(self,action):
        # 系统当前状态
        state = self.state
        # 判断系统当前状态是否为终止状态
        if state in self.terminate_states:
            return state,0,True,{}
        #将状态与动作组成字典的键值
        key = "%d_%s"(state,action)

        #状态转移
        if key in self.t:
            next_state = self.t[key]
        else:
            next_state = state
        self.state = next_state

        is_terminal = False

        if next_state in self.terminate_states:
            is_terminal = True

        if key not in self.rewards:
            r = -1.0
        else:
            r = self.rewards[key]

        return next_state,r,is_terminal,{}

    # reset函数建立
    # reset常常用随机的方法初始机器人状态
    def _reset(self):
        self.state = self.states[int(random.random()*len(self.states))]
        return self.state


        # render函数建立
    def _render(self, mode='human', close=False):
        if close:
            if self.viewer is not None:
                self.viewer.close()
                self.viewer = None
            return
        screen_width = 450
        screen_height = 450

        if self.viewer is None:
            # 调用rendering的画图函数
            from gym.envs.classic_control import rendering
            self.viewer = rendering.Viewer(screen_width, screen_height)

            # 创建网格世界，一共12条直线
            self.line1 = rendering.Line((100, 350), (350, 350))
            self.line2 = rendering.Line((100, 300), (350, 300))
            self.line3 = rendering.Line((100, 250), (350, 250))
            self.line4 = rendering.Line((100, 200), (350, 200))
            self.line5 = rendering.Line((100, 150), (350, 150))
            self.line6 = rendering.Line((100, 100), (350, 100))
            self.line7 = rendering.Line((100, 350), (100, 100))
            self.line8 = rendering.Line((150, 350), (150, 100))
            self.line9 = rendering.Line((200, 350), (200, 100))
            self.line10 = rendering.Line((250, 350), (250, 100))
            self.line11 = rendering.Line((300, 350), (300, 100))
            self.line12 = rendering.Line((350, 350), (350, 100))

            # 接下来写墙块，黑色填满代表墙块
            # 创建第一个墙块
            self.wall1 = rendering.make_polygon([(250,350),(300,350), (300,300),(250,300)],filled=True)
            self.wall1.set_color(0, 0, 0)

            # 创建第二个墙块
            self.wall2 = rendering.make_polygon([(250,300),(300,300),(300,250),(250,250)],filled=True)
            self.wall2.set_color(0, 0, 0)

            # 创建第三个墙块
            self.wall3 = rendering.make_polygon([(100, 250), (150, 250), (150,200),(100,200)], filled=True)
            self.wall3.set_color(0, 0, 0)

            # 创建第四个墙块
            self.wall4 = rendering.make_polygon([(150, 250), (200, 250), (200,200),(150,200)], filled=True)
            self.wall4.set_color(0, 0, 0)

            # 创建第五个墙块
            self.wall5 = rendering.make_polygon([(200, 150), (250, 150), (250, 100),(200, 100)], filled=True)
            self.wall5.set_color(0, 0, 0)

            # 创建第六个墙块
            self.wall6 = rendering.make_polygon([(250, 150), (300, 150), (300, 100),(250, 100)], filled=True)
            self.wall6.set_color(0, 0, 0)

            # 创建第七个墙块
            self.wall7 = rendering.make_polygon([(300, 150), (350, 150), (350, 100),(300, 100)], filled=True)
            self.wall7.set_color(0, 0, 0)

            # 创建出口，用三角形表示
            self.goal = rendering.make_polygon([(325,245),(300,205),(350,205)],
                                                filled=True)
            self.goal.set_color(1, 0.9, 0)

            # 创建机器人，用不同颜色的圆表示
            self.robot = rendering.make_circle(15)
            self.robotrans = rendering.Transform()
            self.robot.add_attr(self.robotrans)
            self.robot.set_color(0.8, 0.6, 0.4)

            # 给11条直线设置颜色，并将这些创建的对象添加到几何中
            self.line1.set_color(0, 0, 0)
            self.line2.set_color(0, 0, 0)
            self.line3.set_color(0, 0, 0)
            self.line4.set_color(0, 0, 0)
            self.line5.set_color(0, 0, 0)
            self.line6.set_color(0, 0, 0)
            self.line7.set_color(0, 0, 0)
            self.line8.set_color(0, 0, 0)
            self.line9.set_color(0, 0, 0)
            self.line10.set_color(0, 0, 0)
            self.line11.set_color(0, 0, 0)
            self.line12.set_color(0, 0, 0)

            self.viewer.add_geom(self.line1)
            self.viewer.add_geom(self.line2)
            self.viewer.add_geom(self.line3)
            self.viewer.add_geom(self.line4)
            self.viewer.add_geom(self.line5)
            self.viewer.add_geom(self.line6)
            self.viewer.add_geom(self.line7)
            self.viewer.add_geom(self.line8)
            self.viewer.add_geom(self.line9)
            self.viewer.add_geom(self.line10)
            self.viewer.add_geom(self.line11)
            self.viewer.add_geom(self.line12)
            self.viewer.add_geom(self.wall1)
            self.viewer.add_geom(self.wall2)
            self.viewer.add_geom(self.wall3)
            self.viewer.add_geom(self.wall4)
            self.viewer.add_geom(self.wall5)
            self.viewer.add_geom(self.wall6)
            self.viewer.add_geom(self.wall7)
            self.viewer.add_geom(self.goal)
            self.viewer.add_geom(self.robot)


        # 根据这两个向量和机器人当前状态，就可以设置机器人当前的圆心坐标
        if self.state is None: return None
        self.robotrans.set_translation(self.x[self.state - 1], self.y[self.state - 1])


        return self.viewer.render(return_rgb_array=mode =='rgb_array')

在classic_control\_init_.py中添加

python">from gym.envs.classic_control.maze_mdp import MazeEnv

在envs/_init_.py中添加

python">register(
    id='MazeWorld-v0',
    entry_point = 'gym.envs.classic_control:MazeEnv',
    max_episode_steps=200,
    reward_threshold=100.0,
)