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"""bank19: Using priorities to increase the clerks for long queues"""
## Model components ------------------------
tracing=0
if tracing:
from SimPy.SimulationTrace import *
else:
from SimPy.Simulation 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))
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 " % (now(), self.name))
yield request, self, counter
print("%8.4f %s: Got counter " % (now(), self.name))
tib = expovariate(1.0 / timeInBank)
yield hold, self, tib
yield release, self, counter
print("%8.4f %s: Finished " % (now(), self.name))
class ClerkProcess(Process):
""" This process removes a clerk from the counter
immediately."""
def serverProc(self):
while True:
# immediately grab the clerk
yield request, self, counter, 100
print("%8.4f %s: leaves. Free:"\
"%d, %d waiting" % (now(), self.name, counter.n, len(counter.waitQ)))
yield waituntil, self, queuelong
yield release, self, counter
print("%8.4f %s: needed . Free:"\
"%d, %d waiting" % (now(), self.name, counter.n, len(counter.waitQ)))
yield waituntil, self, queueshort
def queuelong():
return len(counter.waitQ) > 2
def queueshort():
return len(counter.waitQ) == 0
## Experiment data -------------------------
maxTime = 200.0 # minutes
counter = Resource(2, name="Clerk", qType=PriorityQ)
## Model ----------------------------------
def model(SEED=393939):
seed(SEED)
initialize()
clerk1 = ClerkProcess('Clerk')
activate(clerk1, clerk1.serverProc())
source = Source('Source')
activate(source, source.generate(number=20, rate=0.1), at=0.0)
simulate(until=maxTime)
## Experiment ----------------------------------
model()
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