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""" bank24_OO. BCC system with several counters """
from SimPy.Simulation import Simulation, Process, Resource, hold, request, release
from random import expovariate, seed
## Model components ------------------------
class Source(Process):
""" Source generates customers randomly """
def generate(self, number, meanTBA):
for i in range(number):
c = Customer(name="Customer%02d" % (i), sim=self.sim)
self.sim.activate(c, c.visit())
t = expovariate(1.0 / meanTBA)
yield hold, self, t
class Customer(Process):
""" Customer arrives, is served and leaves """
def visit(self):
arrive = self.sim.now()
print("%8.4f %s: Here I am " % (self.sim.now(), self.name))
if len(self.sim.k.waitQ) < maxInQueue: # the test
yield request, self, self.sim.k
wait = self.sim.now() - arrive
print("%8.4f %s: Wait %6.3f" % (self.sim.now(), self.name, wait))
tib = expovariate(1.0 / timeInBank)
yield hold, self, tib
yield release, self, self.sim.k
print("%8.4f %s: Finished " % (self.sim.now(), self.name))
else:
Customer.numBalking += 1
print("%8.4f %s: BALKING " % (self.sim.now(), self.name))
## Model
class BankModel(Simulation):
def run(self, aseed):
""" PEM """
seed(aseed)
Customer.numBalking = 0
self.k = Resource(capacity=numServers,
name="Counter", unitName="Clerk", sim=self)
s = Source('Source', sim=self)
self.activate(s, s.generate(number=maxNumber, meanTBA=ARRint), at=0.0)
self.simulate(until=maxTime)
## Experiment data -------------------------------
timeInBank = 12.0 # mean, minutes
ARRint = 10.0 # mean interarrival time, minutes
numServers = 1 # servers
maxInSystem = 2 # customers
maxInQueue = maxInSystem - numServers
maxNumber = 8
maxTime = 4000.0 # minutes
theseed = 12345
## Experiment --------------------------------------
mymodel = BankModel()
mymodel.run(aseed=theseed)
## Results -----------------------------------------
nb = float(Customer.numBalking)
print("balking rate is %8.4f per minute" % (nb / mymodel.now()))
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