"""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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