请写出文献中算法的完整python代码
时间: 2024-10-23 21:06:43 浏览: 25
基于Python语言构建神经网络识别手写数字的研究.pdf
由于提供的文献主要描述了算法的设计和实验结果,并没有提供具体的Python代码实现,因此无法直接从文献中提取完整的Python代码。不过,我可以帮助您根据文献中的描述,编写一个大致的框架代码。这个框架代码将包括状态空间定义、动作空间定义、奖励函数设计以及训练过程的主要步骤。
以下是一个基于文献描述的简化版Python代码示例:
```python
import numpy as np
import tensorflow as tf
from collections import deque
import random
class USVEnvironment:
def __init__(self):
self.state_size = 10 # Example state size
self.action_size = 11 # Discrete action space
self.reset()
def reset(self):
# Reset the environment to initial state
self.os_position = np.array([10, 20])
self.os_heading = 0
self.ts_positions = [np.array([20, 5]), np.array([20, 35])]
self.ts_headings = [45, -45]
self.nif = self.calculate_nif()
self.done = False
return self.get_state()
def step(self, action):
# Apply action and get new state, reward, done
self.update_os(action)
self.update_ts()
self.nif = self.calculate_nif()
reward = self.calculate_reward()
self.done = self.check_collision() or self.reached_target()
return self.get_state(), reward, self.done
def update_os(self, action):
# Update own ship's position and heading based on action
delta_heading = action * 5 # Example action scaling
self.os_heading += delta_heading
self.os_position += np.array([np.cos(np.radians(self.os_heading)), np.sin(np.radians(self.os_heading))]) * 2.6
def update_ts(self):
# Update target ship positions
for i, ts_heading in enumerate(self.ts_headings):
self.ts_positions[i] += np.array([np.cos(np.radians(ts_heading)), np.sin(np.radians(ts_heading))]) * 1.8
def calculate_nif(self):
# Calculate Navigation Impact Factor (NIF)
nifs = []
for ts_pos, ts_heading in zip(self.ts_positions, self.ts_headings):
distance = np.linalg.norm(self.os_position - ts_pos)
bearing_angle = np.arctan2(ts_pos[1] - self.os_position[1], ts_pos[0] - self.os_position[0])
bearing_angle = np.degrees(bearing_angle) % 360
nif = self.fuzzy_inference(distance, bearing_angle)
nifs.append(nif)
return nifs
def fuzzy_inference(self, distance, bearing_angle):
# Simplified fuzzy inference for NIF
if distance < 7:
if 5 <= bearing_angle <= 112.5:
return 1.0 # High NIF
elif 112.5 < bearing_angle <= 180:
return 0.5 # Medium NIF
else:
return 0.0 # Low NIF
else:
return 0.0
def calculate_reward(self):
# Calculate reward based on NIF, COLREGs, etc.
r_vo = self.dynamic_obstacle_avoidance_reward()
r_g = self.target_reward()
r_c = self.boundary_reward()
r_da = self.dynamic_approach_reward()
r_sa = self.static_approach_reward()
r_t = self.turning_reward()
r_clgs = self.colregs_reward()
return r_vo + r_g + r_c + r_da + r_sa + r_t + r_clgs
def dynamic_obstacle_avoidance_reward(self):
# Example VO-based reward
if any(nif > 0.5 for nif in self.nif):
return -1.0
else:
return 0.0
def target_reward(self):
# Example target reward
target_position = np.array([80, 45])
distance_to_target = np.linalg.norm(self.os_position - target_position)
if distance_to_target < 2:
return 1.0
else:
return 0.0
def boundary_reward(self):
# Example boundary reward
if 0 <= self.os_position[0] <= 90 and 0 <= self.os_position[1] <= 40:
return 0.0
else:
return -1.0
def dynamic_approach_reward(self):
# Example dynamic approach reward
return 0.0
def static_approach_reward(self):
# Example static approach reward
return 0.0
def turning_reward(self):
# Example turning reward
return -abs(self.os_heading / 180)
def colregs_reward(self):
# Example COLREGs reward
for nif, ts_pos, ts_heading in zip(self.nif, self.ts_positions, self.ts_headings):
if nif > 0.5:
bearing_angle = np.arctan2(ts_pos[1] - self.os_position[1], ts_pos[0] - self.os_position[0])
bearing_angle = np.degrees(bearing_angle) % 360
if 5 <= bearing_angle <= 112.5:
return -1.0
return 0.0
def check_collision(self):
# Check for collision
for ts_pos in self.ts_positions:
if np.linalg.norm(self.os_position - ts_pos) < 2:
return True
return False
def reached_target(self):
# Check if target is reached
target_position = np.array([80, 45])
distance_to_target = np.linalg.norm(self.os_position - target_position)
return distance_to_target < 2
def get_state(self):
# Get the current state
state = np.concatenate([self.os_position, [self.os_heading], self.nif])
return state
class DuelingDQN(tf.keras.Model):
def __init__(self, state_size, action_size):
super(DuelingDQN, self).__init__()
self.dense1 = tf.keras.layers.Dense(128, activation='relu')
self.dense2 = tf.keras.layers.Dense(128, activation='relu')
self.value = tf.keras.layers.Dense(1)
self.advantage = tf.keras.layers.Dense(action_size)
def call(self, state):
x = self.dense1(state)
x = self.dense2(x)
value = self.value(x)
advantage = self.advantage(x)
q_values = value + (advantage - tf.reduce_mean(advantage, axis=1, keepdims=True))
return q_values
def train_dqn(env, episodes=40000, max_steps=100, batch_size=1024, gamma=0.95, epsilon=0.995, epsilon_decay=0.00005):
state_size = env.state_size
action_size = env.action_size
replay_buffer = deque(maxlen=1000000)
dqn = DuelingDQN(state_size, action_size)
target_dqn = DuelingDQN(state_size, action_size)
optimizer = tf.keras.optimizers.Adam(lr=0.0003)
for episode in range(episodes):
state = env.reset()
total_reward = 0
for step in range(max_steps):
if np.random.rand() < epsilon:
action = np.random.choice(action_size)
else:
q_values = dqn(tf.expand_dims(state, axis=0))
action = tf.argmax(q_values[0]).numpy()
next_state, reward, done = env.step(action)
replay_buffer.append((state, action, reward, next_state, done))
state = next_state
total_reward += reward
if len(replay_buffer) > batch_size:
minibatch = random.sample(replay_buffer, batch_size)
states, actions, rewards, next_states, dones = zip(*minibatch)
states = np.array(states)
actions = np.array(actions)
rewards = np.array(rewards)
next_states = np.array(next_states)
dones = np.array(dones)
target_q_values = target_dqn(next_states).numpy()
max_q_values = np.max(target_q_values, axis=1)
targets = rewards + gamma * max_q_values * (1 - dones)
with tf.GradientTape() as tape:
q_values = dqn(states)
action_indices = tf.stack([tf.range(batch_size), actions], axis=1)
chosen_q_values = tf.gather_nd(q_values, action_indices)
loss = tf.reduce_mean(tf.square(targets - chosen_q_values))
gradients = tape.gradient(loss, dqn.trainable_variables)
optimizer.apply_gradients(zip(gradients, dqn.trainable_variables))
if step % 10 == 0:
target_dqn.set_weights(dqn.get_weights())
if done:
break
epsilon = max(epsilon * (1 - epsilon_decay), 0.01)
print(f"Episode {episode}, Total Reward: {total_reward}")
if __name__ == "__main__":
env = USVEnvironment()
train_dqn(env)
```
### 说明
1. **环境类 (`USVEnvironment`)**: 定义了环境的状态、动作、奖励等方法。
2. **深度神经网络模型 (`DuelingDQN`)**: 使用Keras构建了一个双流DQN模型。
3. **训练函数 (`train_dqn`)**: 实现了DQN的训练过程,包括经验回放池、ε-贪婪策略、目标网络更新等。
请注意,这只是一个简化版的实现,实际应用中可能需要更复杂的环境建模、更多的超参数调优以及更详细的奖励函数设计。希望这个示例能为您提供一个良好的起点。
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