Question

我有一台服务器，一次最多可以服务3个客户。我将其建模为带有Resource的SimPy capacity=3，如下所示。 如何更新我的代码，以便每当有新客户到达时，如果服务器的所有容量都被利用，新客户就会被遗忘？

我已经阅读了文档，但是找不到适合这种情况的示例。


SERVERS= 3

class Servers:

    def __init__(self, env):
        self.cashier = simpy.Resource(env, capacity= SERVERS)

def Customer(name, env, servers):
    print('Customer %s arriving at %s' % (name, env.now))
    with servers.cashier.request() as req:
        yield req
        print('Customer %s starts being served at %s' % (name, env.now))
        yield env.timeout(35)
        print('Customer %s done served at %s' % (name, env.now))

def customer_generator(env, servers):
    for i in range(100):
        env.process(Customer(i, env, servers))
        yield env.timeout(5)

env = simpy.Environment()
servers = Servers(env)
cus_generator = env.process(customer_generator(env, servers))
env.run(1000)

Answer 1

SimPy提供了一种简单的方法来检查当前正在使用多少资源的容量。可以使用<resource>.count（link to API）来完成。

您的示例可以进行如下修改：

SERVERS= 3

class Servers:

    def __init__(self, env):
        self.cashier = simpy.Resource(env, capacity= SERVERS)

def Customer(name, env, servers):
    print('Customer %s arriving at %s' % (name, env.now))

    # check if any of the cashiers are free:
    if servers.cashier.count < servers.cashier.capacity:
        with servers.cashier.request() as req:
            yield req
            print('Customer %s starts being served at %s' % (name, env.now))
            yield env.timeout(35)
            print('Customer %s done served at %s' % (name, env.now))
    else:
        print('Customer %s leaving as there was no cashier free to serve them' % (name))

def customer_generator(env, servers):
    for i in range(100):
        env.process(Customer(i, env, servers))
        yield env.timeout(5)

env = simpy.Environment()
servers = Servers(env)
cus_generator = env.process(customer_generator(env, servers))
env.run(1000)

请注意，随着该函数的结束，客户流程将自动在else分支中被销毁（被遗忘），而无需点击其他yield。

如果当时所有资源都在使用中，该如何忘记客户

1 个答案: