不调用simpy库的排队模型系统仿真python代码

下面是一个简单的排队模型系统仿真python代码，不使用SimPy库：

import random

class Customer:
    def __init__(self, id, arrival_time):
        self.id = id
        self.arrival_time = arrival_time
        self.service_start_time = None
        self.service_end_time = None

    def __str__(self):
        return f"Customer {self.id}"

class Queue:
    def __init__(self):
        self.customers = []

    def add_customer(self, customer):
        self.customers.append(customer)

    def next_customer(self):
        if len(self.customers) > 0:
            return self.customers.pop(0)
        else:
            return None

class Server:
    def __init__(self):
        self.current_customer = None
        self.total_service_time = 0
        self.total_customers_served = 0

    def is_busy(self):
        return self.current_customer is not None

    def start_service(self, customer, current_time):
        self.current_customer = customer
        self.current_customer.service_start_time = current_time

    def end_service(self, current_time):
        self.current_customer.service_end_time = current_time
        self.total_service_time += current_time - self.current_customer.service_start_time
        self.total_customers_served += 1
        self.current_customer = None

def run_simulation(num_customers, interarrival_mean, service_time_mean):
    server = Server()
    queue = Queue()
    customers = []
    for i in range(num_customers):
        interarrival_time = random.expovariate(1.0/interarrival_mean)
        arrival_time = 0 if i == 0 else customers[i-1].arrival_time + interarrival_time
        service_time = random.expovariate(1.0/service_time_mean)
        customers.append(Customer(i+1, arrival_time))
        queue.add_customer(customers[i])
        print(f"Customer {i+1} arrives at time {arrival_time:.2f}")

    current_time = 0
    while len(customers) > server.total_customers_served:
        if not server.is_busy():
            next_customer = queue.next_customer()
            if next_customer is not None:
                server.start_service(next_customer, current_time)
                print(f"Customer {next_customer.id} starts service at time {current_time:.2f}")
        else:
            if current_time >= server.current_customer.service_start_time + service_time:
                server.end_service(current_time)
                print(f"Customer {server.current_customer.id} ends service at time {current_time:.2f}")

        current_time += 0.1

    avg_service_time = server.total_service_time / server.total_customers_served
    print(f"\nSimulation results:\nTotal customers served: {server.total_customers_served}")
    print(f"Average service time: {avg_service_time:.2f}")

run_simulation(10, 1, 2)

这个代码模拟了一个简单的排队系统，每个顾客的到达时间和服务时间都是随机的。在模拟的过程中，程序将打印出每个顾客的到达时间、开始服务时间和结束服务时间，以及模拟结果，包括服务的总时间和平均服务时间。