# CarWashMultPar.py: same as CarWash.py, but which runs some # combinations of input parameter values # usage: # python CarWashMultPar.py # simulates a carwash; cars queue up at the entrance; each car chooses # one of two grades of wash, MostlyClean (1.0 unit of time) and Gleaming # (2.0 units of time); there is only one bay in the carwash, so only one # is served at a time; at the exit there is a buffer space where cars # wait to go out onto the street; cross traffic does not stop, so a car # must wait for a large enough gap in the traffic in order to move out # onto the street # ArrRate = rate of arrivals of calls to carwash (reciprocal of mean # time between arrivals) # PropMostlyClean = proportion of cars that opt for the MostlyClean wash # BufSize = number of cars that can fit in the exit buffer # CrossRate = rate of arrivals of cars on the street passing the carwash # ExitTime = time needed for one car to get out onto the street # MaxSimtime = amount of time to simulate # basic strategy of the simulation: model the carwash itself as a # Resource, and do the same for the buffer and the front spot in the # buffer; when a car acquires the latter, it watches for a gap big # enough to enter the street import sys,random from SimPy.Simulation import * # RPy: import RPy from rpy import * class Globals: Rnd = random.Random(12345) Debug = False class Street(Process): CrossRate = None ExitTime = None NextArrival = None # time of next street arrival CrossArrive = SimEvent() def Run(self): while 1: TimeToNextArrival = Globals.Rnd.expovariate(Street.CrossRate) Street.NextArrival = now() + TimeToNextArrival Street.CrossArrive.signal() # tells car at front of buffer to # check new TimeToNextArrival yield hold,self,TimeToNextArrival if Globals.Debug: print print 'time',now() print 'street arrival' class Car(Process): NextID = 0 # for debugging PropMostlyClean = None CurrentCars = [] # for debugging and code verification TotalWait = 0.0 # total wait times of all cars, from arrival to # carwash to exit onto the street TotalBufTime = 0.0 # total time in buffer for all cars NStuckInBay = 0 # number of cars stuck in bay when wash done, due to # full buffer AllDone = 0 # number of cars that have gotten onto the street def __init__(self): Process.__init__(self) self.ID = Car.NextID Car.NextID += 1 self.ArrTime = None # time this car arrived at carwash self.WashDoneTime = None # time this car will finish its wash self.LeaveTime = None # time this car will exit self.StartBufTime = None # start of period in buffer def Run(self): # simulates one call self.State = 'waiting for bay' Car.CurrentCars.append(self) self.ArrTime = now() if Globals.Debug: ShowStatus('carwash arrival') yield request,self,CarWash.Bay self.State = 'in bay' if Globals.Rnd.uniform(0,1) < Car.PropMostlyClean: WashTime = 1.0 else: WashTime = 2.0 self.WashDoneTime = now() + WashTime if Globals.Debug: ShowStatus('start wash') yield hold,self,WashTime self.State = 'waiting for buffer' self.WashDoneTime = None if Globals.Debug: ShowStatus('wash done') if CarWash.Buf.n == 0: Car.NStuckInBay += 1 yield request,self,CarWash.Buf self.StartBufTime = now() yield release,self,CarWash.Bay self.State = 'in buffer' if Globals.Debug: ShowStatus('got into buffer') yield request,self,CarWash.BufFront # OK, now wait to get out onto the street; every time a new car # arrives in cross traffic, it will signal us to check the new # next arrival time while True: PossibleLeaveTime = now() + Street.ExitTime if Street.NextArrival >= PossibleLeaveTime: self.State = 'on the way out' self.LeaveTime = PossibleLeaveTime if Globals.Debug: ShowStatus('leaving') yield hold,self,Street.ExitTime Car.CurrentCars.remove(self) self.LeaveTime = None Car.TotalWait += now() - self.ArrTime Car.TotalBufTime += now() - self.StartBufTime if Globals.Debug: ShowStatus('gone') Car.AllDone += 1 yield release,self,CarWash.BufFront yield release,self,CarWash.Buf return yield waitevent,self,Street.CrossArrive class CarWash(Process): ArrRate = None BufSize = None Buf = None # will be Resource(BufSize) instance representing buffer BufFront = Resource(1) # front buffer slot, by the street NextArrival = None # time of next carwash arrival (for debugging/code # verification) Bay = Resource(1) # the carwash def __init__(self): Process.__init__(self) def Run(self): # arrivals while 1: TimeToNextArrival = Globals.Rnd.expovariate(CarWash.ArrRate) CarWash.NextArrival = now() + TimeToNextArrival yield hold,self,TimeToNextArrival C = Car() activate(C,C.Run()) def ShowStatus(msg): # for debugging and code verification print print 'time', now() print msg print 'current cars:' for C in Car.CurrentCars: print ' ',C.ID,C.State, if C.WashDoneTime != None: print 'wash will be done at',C.WashDoneTime elif C.LeaveTime != None: print 'gone at',C.LeaveTime else: print print 'next carwash arrival at',CarWash.NextArrival print 'next street arrival at',Street.NextArrival def main(): SimResults = [] MaxSimtime = 100.0 CarWash.BufSize = 1 Car.PropMostlyClean = 0.5 Street.ExitTime = 0.5 for i in range(5): CarWash.ArrRate = 0.1 + 5*i for j in range(5): CarWash.Buf = Resource(CarWash.BufSize) Street.CrossRate = 1.5 + j*0.1 initialize() CWArr = CarWash() activate(CWArr,CWArr.Run()) StArr = Street() activate(StArr,StArr.Run()) simulate(until=MaxSimtime) MeanTotalWait = Car.TotalWait/Car.AllDone # RPy: put all the output in one long list, rather than # having to deal with two-dimensional lists SimResults.extend([CarWash.ArrRate,Street.CrossRate,MeanTotalWait]) # RPy: main code is here; load wireframe(), put list SimResults in R # namespace, form matrix, convert to data frame, plot 3-D r.library('lattice') r.assign('simres',SimResults) r('sr <- matrix(simres,ncol=3,byrow=TRUE)') r('sr <- as.data.frame(sr)') r('plot(wireframe(V3 ~ V1+V2,sr))') while 1: continue if __name__ == '__main__': main()