我正在研究以下强化学习问题:我有一瓶固定容量(比如 5 升)。在瓶子的底部有公鸡去除水。去除水的分布不固定。我们可以从瓶子中取出任意数量的水,即 [0, 5] 之间的任意连续值。
在瓶子的顶部安装了一个水龙头,用于将水注入瓶子中。RL 剂可以在瓶子中填充 [0, 1, 2, 3, 4] 升。初始瓶液位是 [0, 5] 之间的任何值。
我想在这种环境中训练代理以获得最佳的动作顺序,这样瓶子就不会变空和溢出,这意味着需要持续供应水。
动作空间 = [0, 1, 2, 3, 4] 离散空间
观察空间 = [0, 瓶子容量] 即 [0, 5] 连续空间
奖励逻辑=如果瓶子因动作空了给予负奖励;如果由于行动导致瓶子溢出,则给予负面奖励
我决定使用python来创建一个环境。
from gym import spaces
import numpy as np
class WaterEnv():
def __init__(self, BottleCapacity = 5):
## CONSTANTS
self.MinLevel = 0 # minimum water level
self.BottleCapacity = BottleCapacity # bottle capacity
# action space
self.action_space = spaces.Discrete(self.BottleCapacity)
# observation space
self.observation_space = spaces.Box(low=self.MinLevel, high=self.BottleCapacity,
shape=(1,))
# initial bottle level
self.initBlevel = self.observation_space.sample()
def step(self, action):
# water qty to remove
WaterRemoveQty = np.random.uniform(self.MinLevel, self.BottleCapacity, 1)
# updated water level after removal of water
UpdatedWaterLevel = (self.initBlevel - WaterRemoveQty)
# add water - action taken
UpdatedWaterLevel_ = UpdatedWaterLevel + action
if UpdatedWaterLevel_ <= self.MinLevel:
reward = -1
done = True
elif UpdatedWaterLevel_ > self.BottleCapacity:
reward = -1
done = True
else:
reward = 0.5
done = False
return UpdatedWaterLevel_, reward, done
def reset(self):
"""
Reset the initial bottle value
"""
self.initBlevel = self.observation_space.sample()
return self.initBlevel
import random
from collections import deque
from keras.models import Sequential
from keras.layers import Dense
from keras.optimizers import sgd
class DQNAgent:
def __init__(self, state_size, action_size):
self.state_size = state_size
self.action_size = action_size
self.memory = deque(maxlen=2000) # memory size
self.gamma = 0.99 # discount rate
self.epsilon = 1.0 # exploration rate
self.epsilon_min = 0.01 # minmun exploration rate
self.epsilon_decay = 0.99 # exploration decay
self.learning_rate = 0.001 # learning rate
self.model = self._build_model()
def _build_model(self):
# Neural Net for Deep-Q learning Model
model = Sequential()
model.add(Dense(256, input_dim=self.state_size, activation='relu'))
model.add(Dense(256, activation='relu'))
model.add(Dense(self.action_size, activation='linear'))
model.compile(loss='mse',
optimizer=sgd(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 random.randrange(self.action_size)
act_values = self.model.predict(state)
return np.argmax(act_values[0]) # returns action
def replay(self, batch_size):
minibatch = random.sample(self.memory, batch_size)
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
# create iSilo enviroment object
env = WaterEnv()
state_size = env.observation_space.shape[0]
action_size = env.action_space.n
minibatch = 32
# Initialize agent
agent = DQNAgent(state_size, action_size)
done = False
lReward = [] # carry the reward upto end of simulation
rewardAll = 0
XArray = [] # carry the actions upto end of simulation
EPOCHS = 1000
for e in range(EPOCHS):
#state = np.reshape(state, [1, 1])
# reset state in the beginning of each epoch
state = env.reset()
time_t = 0
rewardAll = 0
while True:
# Decide action
#state = np.reshape(state, [1, 1])
action = agent.act(state)
next_state,reward, done = env.step(action)
#reward = reward if not done else -10
# Remember the previous state, action, reward, and done
#next_state = np.reshape(next_state, [1, state_size])
agent.remember(state, action, reward, next_state, done)
# remembering the action for perfrormace check
XArray.append(action)
# Assign next_state the new current state for the next frame.
state = next_state
if done:
print(" episode: {}/{}, score: {}, e: {:.2}"
.format(e, EPOCHS, time_t, agent.epsilon))
break
rewardAll += reward
# experience and reply
if len(agent.memory) > minibatch:
agent.replay(minibatch)
lReward.append(rewardAll) # append the rewards
在运行 1000 个 epoch 后,我观察到代理没有学到任何东西。无法找出问题所在。