交通元胞机模型的Python实现

交通元胞机模型是一种用于模拟交通流动的计算模型，它基于细胞自动机模型，通过将道路划分成小的单元（细胞）来模拟车辆在道路上的运动。下面是一个简单的交通元胞机模型的Python实现：

import numpy as np
import random

# 定义道路长度和车道数
length = 100
lanes = 3

# 定义车道宽度和车辆长度
lane_width = 4
vehicle_length = 5

# 定义车速和加速度
max_speed = 20
acceleration = 1

# 定义车辆密度和交通灯周期
density = 0.3
light_cycle = 10

# 定义道路状态
road = np.zeros((length, lanes))

# 定义车辆类
class Vehicle:
    def __init__(self, lane, position, speed):
        self.lane = lane
        self.position = position
        self.speed = speed

# 初始化车辆
vehicles = []
for lane in range(lanes):
    for position in range(length):
        if random.uniform(0, 1) < density:
            speed = random.randint(0, max_speed)
            vehicle = Vehicle(lane, position, speed)
            vehicles.append(vehicle)
            road[position, lane] = 1

# 定义交通灯状态
light = 0

# 定义车辆运动函数
def move(vehicles):
    for vehicle in vehicles:
        # 计算前方车辆距离和速度差
        lead_distance = 0
        lead_speed = 0
        for i in range(1, max_speed):
            if road[(vehicle.position + i) % length, vehicle.lane] == 1:
                lead_distance = i - 1
                lead_speed = vehicles[(vehicles.index(vehicle) + i - 1) % len(vehicles)].speed
                break
        speed_difference = lead_speed - vehicle.speed
        
        # 根据速度差计算加速度
        if speed_difference >= 0:
            acceleration = min(speed_difference, vehicle.speed)
        else:
            acceleration = min(-speed_difference, max_speed - vehicle.speed)
        
        # 更新车速和位置
        vehicle.speed = min(vehicle.speed + acceleration, max_speed)
        vehicle.position = (vehicle.position + vehicle.speed) % length
        
        # 更新道路状态
        road[:, vehicle.lane] = 0
        for i in range(vehicle_length):
            road[(vehicle.position + i) % length, vehicle.lane] = 1

# 定义交通灯函数
def toggle_light():
    global light
    light = (light + 1) % light_cycle

# 模拟车辆运动
for t in range(100):
    if light == 0:
        toggle_light()
    for i in range(light_cycle):
        move(vehicles)
        if light == i:
            vehicles = sorted(vehicles, key=lambda x: x.position)
            for vehicle in vehicles:
                if vehicle.position >= length - 5:
                    vehicles.remove(vehicle)
                    road[:, vehicle.lane] = 0
            toggle_light()

上述代码使用numpy数组来表示道路状态，使用Python类来表示车辆，并通过move函数来模拟车辆的运动。同时，还定义了toggle_light函数来控制交通灯的状态，并在模拟过程中实现了对交通灯状态的切换。