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"""bank18: A Resource with Priority to vary the number of units"""
## Model components ------------------------
from SimPy.SimulationTrace import *
from random import expovariate, seed
class Source(Process):
""" Source generates customers randomly"""
def generate(self, number, rate):
for i in range(number):
c = Customer(name="Customer%02d" % (i), sim=self.sim)
self.sim.activate(c, c.visit(timeInBank=12.0))
yield hold, self, expovariate(rate)
class Customer(Process):
""" Customer arrives, is served and leaves """
def visit(self, timeInBank):
print("%8.4f %s: Arrived " % (self.sim.now(), self.name))
yield request, self, self.sim.counter
print("%8.4f %s: Got counter " % (self.sim.now(), self.name))
tib = expovariate(1.0 / timeInBank)
yield hold, self, tib
yield release, self, self.sim.counter
print("%8.4f %s: Finished " % (self.sim.now(), self.name))
class ClerkProcess(Process):
""" This process removes a clerk from the counter
after an average of 20 minutes.
The clerk returns after 5 minutes """
def serverProc(self):
while True:
# The clerk starts working. Leave after an average of 10 minutes
yield hold, self, expovariate(1.0 / 15.0)
print("%8.4f %s: urgent. Free:"\
"%d, %d waiting" % (self.sim.now(), self.name,
self.sim.counter.n, len(self.sim.counter.waitQ)))
# The first free clerk is removed
yield request, self, self.sim.counter, 100
print("%8.4f %s: leaves. Free:"\
"%d, %d waiting" % (self.sim.now(), self.name,
self.sim.counter.n, len(self.sim.counter.waitQ)))
#period away is 3 minutes
yield hold, self, 3.0
#clerk returns
yield release, self, self.sim.counter
print("%8.4f %s: returns. Free:"\
"%d, %d waiting" % (self.sim.now(), self.name,
self.sim.counter.n, len(self.sim.counter.waitQ)))
## Experiment data -------------------------
maxTime = 200.0 # minutes
tracing = 0
## Model ----------------------------------
if tracing:
library = SimulationTrace
else:
library = Simulation
class BankModel(library):
def run(self):
""" PEM """
self.counter = Resource(1, name="Clerk", qType=PriorityQ, sim=self)
clerk1 = ClerkProcess('Clerk', sim=self)
self.activate(clerk1, clerk1.serverProc())
source = Source('Source', sim=self)
self.activate(source, source.generate(number=20, rate=0.1), at=0.0)
self.simulate(until=maxTime)
## Experiment ----------------------------------
seed(393939)
mymodel = BankModel()
mymodel.run()
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