Forums

import numpy as np


class Simulation:



    def generate_interarrival(self):
        return np.random.poisson(1./3)

    def generate_service(self):
        return np.random.poisson(1./4)


    def __init__(self):



        self.queue = []
        self.averageWaitingTime=[]
        self.total_wait=[]

        self.num_in_system = 0

        self.clock = 0.0
        self.t_arrival = self.generate_interarrival()
        self.t_depart = float('inf')

        self.num_arrivals = 0
        self.num_departs = 0
        self.total_wait = 0.0
        self.averageWaitingTime= 0.0




    def advance_time(self):
        t_event =min(self.t_arrival, self.t_depart)
        self.total_wait += self.num_in_system*(t_event - self.clock)

        print self.total_wait, 'customer total wait'



        self.clock = t_event


        if self.t_arrival <=self.t_depart:
            self.handle_arrival_event()
        else:
           self.handle_depart_event()
           self.averageWaitingTime =self.total_wait/self.t_depart
           print  self.averageWaitingTime, ' average waiting time per customer'




    def handle_arrival_event(self ):
        self.num_in_system +=1
        self.num_arrivals += 1

        num_arrivals = self.clock+ self.generate_interarrival() 
        print num_arrivals, ' customer {} interarrival'.format(i)



        if self.num_in_system <=1:
                self.t_depart = self.clock + self.generate_service()

        self.t_arrival = self.clock + self.generate_interarrival()



    def handle_depart_event(self):
        self.num_in_system -=1
        self.num_departs += 1

        num_departs = self.clock 
        print num_departs, ' customer {} departed'.format(i)


        if self.num_in_system>0:
            self.t_depart = self.clock + self.generate_service()
        else:
           self.t_depart = float(' inf')


np.random.seed(0)

s = Simulation()

for i in range (1000):
    s.advance_time()

   import matplotlib.pyplot as plt

plt.plot(s.total_wait)
plt.ylabel('Waiting time(min)')
plt.xlabel('Number of Customers')