Homework III

This assignment will count double.

Due Monday, February 18

This program simulates the operation of a carwash. Here are the details:

• Command-line usage is

     python CarWash.py ArrRate PropMostlyClean BufSize CrossRate ExitTime MaxSimTime
     

  where

  • ArrRate = rate of arrivals of calls to carwash
  • 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 (if the gap is double this size, then two cars can get out etc.)
  • MaxSimtime = amount of time to simulate

• Cars queue up at the entrance of the carwash, which has just one service bay.
• Each car chooses one of two grades of wash, MostlyClean (takes 1.0 unit of time) and Gleaming (2.0 units of time).
• At the exit of the service bay there is a buffer space where cars wait to go out onto the street. If this fills, then any car in the service bay must stay there, blocking other cars from using it.
• On the street, cross traffic does not stop, so a car exiting the carwash must wait for a large enough gap in the traffic in order to move out onto the street.

Have your program compute the following:

• Mean total wait (from arrival to the carwash to completion of exiting onto the street).
• Mean wait in the buffer (includes times in exiting to street).
• Mean number of cars in buffer, using Little's Rule.
• Mean number of cars in buffer, using alternate method.
• Proportion of cars blocked from exiting bay when they finish the wash.

Sample outputs:

localhost:~/156% python CarWash.py 0.2 0.5 1000 0.001 0.5 100000
number of cars getting onto the street 19744
mean total wait: 2.34899465619
mean wait in buffer: 0.500106741359
proportion of cars blocked from exiting bay: 0.0
mean number of cars in buffer, using Little's Rule: 0.100021348272
mean number of cars in buffer, using alternate method: 0.0987390987391
localhost:~/156%
localhost:~/156% python CarWash.py 0.2 0.5 1000 1 0.5 100000
number of cars getting onto the street 19888
mean total wait: 2.48991624748
mean wait in buffer: 0.653478058138
proportion of cars blocked from exiting bay: 0.0
mean number of cars in buffer, using Little's Rule: 0.130695611628
mean number of cars in buffer, using alternate method: 0.129885129885
localhost:~/156%
ocalhost:~/156% python CarWash.py 0.2 0.5 1000 4 0.5 100000
number of cars getting onto the street 19993
mean total wait: 3.88205234856
mean wait in buffer: 2.0331090161
proportion of cars blocked from exiting bay: 0.0
mean number of cars in buffer, using Little's Rule: 0.40662180322
mean number of cars in buffer, using alternate method: 0.406521406521

calhost:~/156%
localhost:~/156% python CarWash.py 0.2 0.5 1 4 0.5 100000
number of cars getting onto the street 20045
mean total wait: 3.95367805751
mean wait in buffer: 1.58312694729
proportion of cars blocked from exiting bay: 0.205836867049
mean number of cars in buffer, using Little's Rule: 0.316625389458
mean number of cars in buffer, using alternate method: 0.317307317307
localhost:~/156%
localhost:~/156% python CarWash.py 0.2 0.5 2 4 0.5 100000
number of cars getting onto the street 20072
mean total wait: 3.9251021552
mean wait in buffer: 1.93775043515
proportion of cars blocked from exiting bay: 0.0479748916455
mean number of cars in buffer, using Little's Rule: 0.387550087029
mean number of cars in buffer, using alternate method: 0.388949388949
localhost:~/156%
localhost:~/156% python CarWash.py 0.2 0.5 3 4 0.5 100000
number of cars getting onto the street 20153
mean total wait: 3.86862181231
mean wait in buffer: 1.99293681777
proportion of cars blocked from exiting bay: 0.0101225623977
mean number of cars in buffer, using Little's Rule: 0.398587363554
mean number of cars in buffer, using alternate method: 0.401648401648
localhost:~/156%
localhost:~/156% python CarWash.py 0.2 0.5 3 1 1 100000
number of cars getting onto the street 20012
mean total wait: 4.03079282244
mean wait in buffer: 2.14578436626
proportion of cars blocked from exiting bay: 0.0116424324189
mean number of cars in buffer, using Little's Rule: 0.429156873252
mean number of cars in buffer, using alternate method: 0.429451429451
localhost:~/156%
localhost:~/156% python CarWash.py 0.3 0.5 1 1 1 100000
number of cars getting onto the street 29940
mean total wait: 4.94098842573
mean wait in buffer: 1.71364276301
proportion of cars blocked from exiting bay: 0.292265045755
mean number of cars in buffer, using Little's Rule: 0.514092828902
mean number of cars in buffer, using alternate method: 0.513092513093