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tesfatsi AT iastate.edu
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Guide for Newcomers to Agent-Based Modeling
Agent-Based Computational Economics (ACE) Resources
Online ACE Course (self-study eBook)
ACE/CAS Comp Labs and Demo Software
ACE/CAS General Software and Toolkits
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Objectives and Topic Listing:
Topics
John T. Murphy has prepared a
useful tutorial titled
Java Basics (html,7pp)
that provides a quick guide to basic Java concepts to help people navigate
through the writing of a Java program.
The latest version of Repast can be downloaded as freeware
from the
Repast Sourceforge Site.
This download includes a number of stand-alone Repast demonstration models
(demos) that can be opened and run without need for any programming or compilation:
e.g., Conway's Game of Life; GisModel; HeatBugs, Mouse Traps, and SugarScape.
To develop Repast applications, or even to run existing Repast demo models,
it is useful to have some kind of
integrated development environment (IDE) that provides an integrated set of tools
for code development, debugging, compilation, running, and display.
Free Java IDES such as NetBeans and Eclipse, are available on the web (locate by a Google search). They can
either be downloaded separately or packaged together with the latest version of the Java
Development Kit (JDK), formerly called the Java SDK (Software Development Kit).
John T. Murphy
has prepared a site titled
Agent-Based Modelling Tutorial (html).
This site includes notes on Java basics, notes on Eclipse basics, and a Repast tutorial. The latter tutorial slowly and carefully takes the user through the three basic elements of a Repast model: a Model Object; a Space Object that controls the environment in which action takes place; and an Agent Object. All three aspects are carefully and consistently illustrated in terms of a concrete model example (the "Carry and Drop Model") that is constructed in
31 incremental steps. Graphical depiction via chart and histogram displays are also covered, and source code is provided in a separate zip file.
The Murphy Tutorial can be accessed at the main entry URL above. Murphy provides detailed verbal explanations of each of the 31 steps in this tutorial. However, some additional helpful notes on the first 24 steps, with graphical visualizations of key points, are available as follows:
Important Note on the Murphy Tutorial: Several of the Murphy Tutorial steps make use of (pseudo-)random numbers that are generated using particular classes from a special Java archive (JAR) file called colt.jar. In addition, Murphy Tutorial steps 30 and 31, in which code for a Chart and Histogram are introduced, require certain special plot classes from a JAR file called plot.jar. When I downloaded Repast (Version 3.0) as a zip file, and then unzipped this file with directory structure intact, both colt.jar and plot.jar were in the resulting Repast library ("lib") directory. In addition, the class files for Repast itself were bundled into a JAR file (Repast.jar) found in the Repast main directory. You need to be sure that the paths to all three of these JAR files are in the classpath for the Murphy Tutorial project so the project can find them. For example, I was able to code up, compile, and run the entire Murphy Tutorial project (Steps 1-31) by associating with this project a "required library" directory containing Repast.jar, colt.jar, and plot.jar.
Steven F. Railsback, Steven L. Lytinen, and Stephen K. Jackson have developed a useful site called StupidModel: A Template Model for ABM Platforms
(html).
The "StupidModel" template is implemented in five different platforms: NetLogo; Repast; MASON; Java Swarm; and Objective C Swarm. Although relatively simple, StupidModel includes many commonly used features of agent-based modeling (ABM) platforms.
For assistance with basic set-up and model design tasks for Repast (V3.X), users are urged
to consult the
Repast How-To Documentation and Third-Party Tutorials.
Each step of the Murphy Tutorial (above), while self-sufficiently explained, points
to the appropriate Repast How-To file(s) for additional background information related
to the step being taken for those who wish to view it.
Note: Integrated Development Environments (IDEs) are programs that permit you to write, compile, run, and debug programs from within a single environment.