# LIST OF MODELS using SimPy

Authors: | Tony Vignaux <Vignaux@users.sourceforge.net>, Klaus Muller <Muller@users.sourceforge.net>
SimPy version: | 1.8
Web-site: | http://simpy.sourceforge.net/
Python-Version: | 2.3+

These models are some examples of SimPy use written by several authors and usually developed for other purposes, such as teaching and consulting. They are in a variety of styles. Some have been converted to the new structure accepted by the SimPy users. These are listed first.

# Command Line input and output

## new program structure

MMC.py

> M/M/c (multiple server queue model. This demonstrates both the multiple capacity Resource class and the observe method of the Monitor class. Random arrivals, exponential service-times. (TV)

bakery.py

> Simulation of a bakery with three ovens to answer the following questions: a) What is the mean waiting time for retail and restaurant buyers? b) What is their maximum waiting time? c) What percentage of customer has to wait longer than 15 minutes? This makes a GRAPH of the number of baguettes over time using SimPy.SimPlot. (KGM)

bcc.py
  Determine the probability of rejection of random arrivals to a 2-server system with different service-time distributions. No queues allowed, blocked customers are rejected (BCC). Distributions are Erlang, exponential, and hyperexponential. The theoretical probability is also calculated. (TV)

callCenter.py

> Simulation of a call center with agents with different skills. The model returns the frequency distribution of client waiting times, the percentage of reneging clients, and the load on the agents. This model demonstrates the use of yield get with a filter function. (KGM)

cellphone.py

> Simulation of a cellphone cell with blocking (that is BCC discipline). The program simulates the operation for 10 observation periods and measures the mean and variance of the total time blockedr and the number of times blocking occur in each hour. An observational gap occurs between the observation periods to make each one's measurement independent. (TV)

centralserver.py

> Simulates a primitive central-server model with a single CPU and a single disk. A fixed number of users send "tasks" to the system which are processed and sent back to the user who then thinks for a time before sending a task back. Service times are exponential. This system can be solved analytically. Trace statements have been removed. (TV)

jacksonnetwork.py

> Simulation of a Jackson network with 3 nodes, exponential service times and probability switching. The simulation measures the delay for jobs moving through the system. (TV)

## Miscellaneous Models

bank08renege.py (partial conversion)

> Demo of use of reneging (compound 'yield request') constructs introduced with SimPy 1.6 for reneging after a maximum wait time. Based on bank08.py tutorial.g

Carwash.py

> Demo of using a Store object for implementing master/slave cooperation between processes. Scenario is a carwash installation with multiple machines. Two model implementations are shown, one with the carwash as master in the cooperation, and the other with the car as master.

CellularAutomata.py

> A simple simulation of two-dimensional cellular automata. Does the game of Life. (KGM)

needResources.py

> Demo of waitUntil capability introduced in SimPy 1.5. It simulates three workers each requiring a set of tools to do their jobs. Tools are shared, scarce resources for which they compete.

demoSimPyEvents.py

> Demo of the event signalling constructs introduced in SimPy 1.5. Three small simulations are included: Pavlov's drooling dogs, an activity simulation where a job is completed after a number of parallel activities, and the simulation of a US-style 4-way stop intersection.

shortestPath_SimPy.py

> A fun example of using SimPy for non-queuing work. It simulates a searcher through a graph, seeking the shortest path. (KGM)

Machineshop.py

> An example of the use of the 'interrupt()' method introduced in SimPy 1.2. It simulates a workshop with n machines which break down and one or more repairmen which have to repair them. (KGM)

Market.py

> Simulation of a supermarket checkout with multiple counters and extended Monitor objects. Written and analysed by David Mertz in an article for developerWorks (). (MM)

SimPy_worker_extend.py

> Factory making widgets with queues for machines. (MM)

Movie_renege.py

> Demo of use of reneging (compound 'yield request') constructs introduced with SimPy 1.6 for reneging at occurrence of an event. Scenario is a movie ticket counter with a limited number of tickets for three movies.

WidgetPacking.py

> Demo of using buffers for producer/consumer scenarios. Scenario is a group of widget producing machines and a widget packer, synchronized via a buffer. Two models are shown: the first uses a Level for buffering non-distinguishable items (widgets), and the second a Store for distinguishable items (widgets of different weight).

# GUI Input

MM1.py
  M/M/1 random-arrivals, exponential service time queue with GUI input. (MM)
GUIdemo.py
  Simulates a firework show.
bank11GUI.py
  A modification of the bank11 simulation with GUI input.
SimGUIStep.py
  A modification of the bank11 simulation with the ability to step between events

# Plot

bank11Plot.py
  A Modification of the bank11 simulation with graphical output. It plots service and waiting times

Created: | 2002-December
Date: | $Date: 2007/01/12 06:03:32 $
Revision: | $Revision: 1.1.1.9 $