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POWhy is this recursive statement wrong?
 

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  1. POWhy is this recursive statement wrong?
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    <p>This is a bank simulation that takes into account 20 different serving lines with a single queue, customers arrive following an exponential rate and they are served during a time that follows a normal probability distribution with mean 40 and standard deviation 20. </p> <p>Things were working just fine till I decided to exclude the negative values given by the normal distribution using this method: </p> <pre><code>def getNormal(self): normal = normalvariate(40,20) if (normal&gt;=1): return normal else: getNormal(self) </code></pre> <p>Which has caused the program to give me this screen every now and then: <a href="http://yfrog.com/2qrecursionp" rel="nofollow noreferrer">SCREEN</a></p> <p>Am I screwing up the recursive call? I don't get why it wouldn't work. I have changed the getNormal() method to:</p> <pre><code>def getNormal(self): normal = normalvariate(40,20) while (normal &lt;=1): normal = normalvariate (40,20) return normal </code></pre> <p>But I'm curious on why the previous recursive statement gets busted.</p> <p>This is the complete source code, in case you're interested.</p> <pre><code>""" bank21: One counter with impatient customers """ from SimPy.SimulationTrace import * from random import * ## Model components ------------------------ class Source(Process): """ Source generates customers randomly """ def generate(self,number): for i in range(number): c = Customer(name = "Customer%02d"%(i,)) activate(c,c.visit(tiempoDeUso=15.0)) validateTime=now() if validateTime&lt;=600: interval = getLambda(self) t = expovariate(interval) yield hold,self,t #esta es la rata de generación else: detenerGeneracion=999 yield hold,self,detenerGeneracion class Customer(Process): """ Customer arrives, is served and leaves """ def visit(self,tiempoDeUso=0): arrive = now() # arrival time print "%8.3f %s: Here I am "%(now(),self.name) yield (request,self,counter),(hold,self,maxWaitTime) wait = now()-arrive # waiting time if self.acquired(counter): print "%8.3f %s: Waited %6.3f"%(now(),self.name,wait) tiempoDeUso=getNormal(self) yield hold,self,tiempoDeUso yield release,self,counter print "%8.3f %s: Completed"%(now(),self.name) else: print "%8.3f %s: Waited %6.3f. I am off"%(now(),self.name,wait) ## Experiment data ------------------------- maxTime = 60*10.5 # minutes maxWaitTime = 12.0 # minutes. maximum time to wait ## Model ---------------------------------- def model(): global counter #seed(98989) counter = Resource(name="Las maquinas",capacity=20) initialize() source = Source('Source') firstArrival= expovariate(20.0/60.0) #chequear el expovariate activate(source, source.generate(number=99999),at=firstArrival) simulate(until=maxTime) def getNormal(self): normal = normalvariate(40,20) if (normal&gt;=1): return normal else: getNormal(self) def getLambda (self): actualTime=now() if (actualTime &lt;=60): return 20.0/60.0 if (actualTime&gt;60)and (actualTime&lt;=120): return 25.0/60.0 if (actualTime&gt;120)and (actualTime&lt;=180): return 40.0/60.0 if (actualTime&gt;180)and (actualTime&lt;=240): return 30.0/60.0 if (actualTime&gt;240)and (actualTime&lt;=300): return 35.0/60.0 if (actualTime&gt;300)and (actualTime&lt;=360): return 42.0/60.0 if (actualTime&gt;360)and (actualTime&lt;=420): return 50.0/60.0 if (actualTime&gt;420)and (actualTime&lt;=480): return 55.0/60.0 if (actualTime&gt;480)and (actualTime&lt;=540): return 45.0/60.0 if (actualTime&gt;540)and (actualTime&lt;=600): return 10.0/60.0 ## Experiment ---------------------------------- model() </code></pre>
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    1. COGlad to see other people still write discrete event simulations. I spent 6 months working on a huge simulation for a graduate thesis 2 years ago.
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      1. POWhy is this recursive statement wrong?
      1. USMr. Will
    2. COIn an orthogonal issue, why are you passing "self" as a parameter to module-level functions where you don't even use it?
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      1. POWhy is this recursive statement wrong?
      1. USCarl Meyer
 

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