pgm11_22.txt

Data Structures And Algorithms With Object-Oriented Design Patterns In Python (2003) source code and

#
# This file contains the Python code from Program 11.22 of
# "Data Structures and Algorithms
# with Object-Oriented Design Patterns in Python"
# by Bruno R. Preiss.
#
# Copyright (c) 2003 by Bruno R. Preiss, P.Eng.  All rights reserved.
#
# http://www.brpreiss.com/books/opus7/programs/pgm11_22.txt
#
class Simulation(object):

    ARRIVAL = 0
    DEPARTURE = 1

    def __init__(self):
        super(Simulation, self).__init__()
        self._eventList = LeftistHeap()
        self._serverBusy = False
        self._numberInQueue = 0
        self._serviceTime = ExponentialRV(100.0)
        self._interArrivalTime = ExponentialRV(100.0)

    def run(self, timeLimit):
        self._eventList.enqueue(self.Event(self.ARRIVAL, 0))
        while not self._eventList.isEmpty:
            evt = self._eventList.dequeueMin()
            t = evt.time
            if t > timeLimit:
                self._eventList.purge()
                break
            if evt.type == self.ARRIVAL:
                if not self._serverBusy:
                    self._serverBusy = True
                    self._eventList.enqueue(
                        self.Event(self.DEPARTURE,
                        t + self._serviceTime.next))
                else:
                    self._numberInQueue += 1
                self._eventList.enqueue(self.Event(self.ARRIVAL,
                    t + self._interArrivalTime.next))
            elif evt.type == self.DEPARTURE:
                if self._numberInQueue == 0:
                    self._serverBusy = False
                else:
                    self._numberInQueue -= 1
                    self._eventList.enqueue(
                        self.Event(self.DEPARTURE,
                        t + self._serviceTime.next))

    # ...