Repast: A Software Toolkit for
Agent-Based Social Science Modeling

Self-Study Guide for Java-Based Repast

Last Updated: 11 February 2025

Site Maintained By: Leigh Tesfatsion Professor Emerita of Economics Courtesy Research Professor of    Electrical & Computer Engineering Heady Hall 260 Iowa State University Ames, Iowa 50011-1054 https://www2.econ.iastate.edu/tesfatsi/ tesfatsi AT iastate.edu

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

Objectives and Topic Listing:

The suite of free open-source agent-based modeling simulation platforms known as Repast (REcursive Porous Agent Simulation Toolkit) was developed by David Sallach and other researchers at the University of Chicago and the Argonne National Laboratory for social science applications.

Repast permits the systematic study of complex system behaviors through controlled and replicable computational experiments. More precisely, Repast provides a core collection of classes for the building and running of agent-based simulations and for the collection and display of data through tables, charts, and graphs. A particularly attractive feature of Repast is its ability to integrate GIS (geographical information science) data directly into simulations.

Repast has been released in multiple versions supporting model development in various programming languages:

1. Repast (Java based);
2. RepastPy (based on the Python Scripting language);
3. Repast.Net (implemented in C# but any .Net language can be used);
4. RepastS (Repast Simphony, Java based, designed for use on workstations and small computing clusters);
5. Repast High Performance Computing (an expert-focused C++-based modeling system designed for use on large computing clusters and supercomputers).

Repast can be run on virtually all modern computing platforms (e.g., Microsoft Windows, Apple Mac OS X, and Linux).

A comprehensive list of documentation for all latest Repast releases, including detailed technical information regarding the installation and use of these releases, is provided at the following site: Repast Documentation (GitHub Repository).

In summer 2004 an informal Repast Study Group was organized at Iowa State University for those wishing to undertake a study of the Repast toolkit. The primary reason for organizing the group was to help participants obtain some facility with Repast through readings, hands-on experience with Repast demos, and simple programming exercises. The objective was to determine the degree to which Repast provides a useful and user-friendly agent-based modeling tool for economics and related fields.

This site, originally developed for Repast Study Group participants, provides links to readings, discussion materials, software, and other resources of potential use to those wishing to embark on a self-study of Repast based on a Java development environment. Although some prior programming experience is desirable, it is not presumed.

0. For Those Who Want to Jump Right In

1. Introduction to CAS/ABM/ACE
   1. What is a Complex Adaptive System (CAS)?
   2. What is Agent-Based Modeling (ABM)?
   3. What is Agent-Based Computational Economics (ACE)?
2. Agent-Oriented Programming
   1. General Overview
   2. Introduction to Java
3. Getting Acquainted with Repast
   1. Background Materials
   2. Downloadable Stand-Alone Repast Demos
4. Programming with Repast
   1. The Repast Software Framework
   2. Repast Development Environments
   3. Repast Documentation and Tutorials
   4. Repast Demos and Applications (Open Source)
   5. Design of Experiments
5. Possible Repast Modeling Application Areas: On-Line Resource Sites

Topics

0. For Those Who Want to Jump Right In

• John T. Murphy's tutorial Java Basics (html,7pp) 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 GitHub Repository 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 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).

• Alan G. Isaac, "The ABM Template Models: A Reformulation with Reference Implementations" (html), Journal of Artificial Societies and Social Simulation 14 (2) 5, March 2011. The author refines materials originally developed by Steven F. Railsback, Steven L. Lytinen, and Stephen K. Jackson to guide students, step by step, through a hands-on construction of an ACE model using sixteen model templates with increasing model capabilities. The sixteen model templates were prepared in a variety of different programming languages, including Java-based RePast. The author also addresses design, flexibility, and ease of use issues relevant to the choice of an agent-based modeling platform.

• For assistance with basic set-up and model design tasks for Repast, users can consult the following site: Repast Documentation (GitHub Repository).

I. Introduction to CAS/ABM/ACE

I.A What is a Complex Adaptive System (CAS)?

• Leigh Tesfatsion, "Complex Adaptive Systems" (pdf,40KB).

• Sunny Y. Auyang, "Synthetic Analysis of Complex Systems I - Theories" (html,11pp), circa 2000.

  Abstract: This thoughtful essay by independent researcher Sunny Auyang addresses the question "what is complexity." The author attempts to extract the commonly shared ideas implicit in many formalized conceptions of complexity and also in the general way that people tend to think about complicated situations.

I.B What is Agent-Based Modeling (ABM)?

• Robert Axelrod and Leigh Tesfatsion, "On-Line Guide for Newcomers to Agent-Based Modeling in the Social Sciences" (html).

  Abstract: This guideline provides a short annotated list of introductory readings for newcomers to agent-based modeling in the social sciences. It also provides pointers to additional readings and software to help interested readers get started on their own agent-based research.

• Leigh Tesfatsion, "Agent-Based Modeling: The Right Mathematics for Social Science?" (SlideSet,KeynoteSSC2021,pdf,1.5MB).

I.C What is Agent-Based Computational Economics (ACE)?

• Leigh tesfatsion, Agent-based Computational Economics (ACE) Website: Homepage (html)

• Leigh Tesfatsion, ACE Tutorial (SlideSet,pdf,408KB).

  Abstract: This tutorial provides a short introduction to the ACE methodology. An ACE labor market study -- specifically, the effects of systematically varied unemployment benefits on employer-employee network formation and worksite cooperation -- is briefly reviewed for concrete illustration.

• Rob Axtell, "Agent-Based Computing in Economics" (SlideSet,pdf,256KB), presented at the VII Trento Summer School, July 2006.

Other introductory source materials on CAS/ABM/ACE

II. Agent-Oriented Programming

II.A General Overview

• Leigh Tesfatsion, Agent-Oriented Programming: An Introduction (pdf,105KB).

• Leigh Tesfatsion, Illustration of Agent-Oriented Programming: Per Bak's Sand Pile Model (pdf,50KB).

• Nigel Gilbert and Pietro Terna, "How to Build and Use Agent-Based Models in Social Science" (pdf,57KB), Discussion Paper, May 18, 1999.

  Abstract: This essay discusses computational modeling as a third way of building social science models. Specific advice is given regarding how to build environments, represent agents, and specify agent behavioral rules. An object-oriented programming approach is stressed.

• Nigel Gilbert and Stephen Bankes, Platforms and Methods for Agent-Based Modeling (pdf,49KB), Proceedings of the National Academy of Sciences, U.S.A., 99 (Suppl. 3), May 14, 2002, 7197-7198.

• Nicholas R. Jennings, "On Agent-Based Software Engineering" (pdf,257KB), Artificial Intelligence 117 (2000), 277-296, copyright © 2002 Elsevier Science B.V. All rights reserved.

  Abstract: "Agent-based computing represents an exciting new synthesis both for Artificial Intelligence (AI) and, more generally, Computer Science. It has the potential to significantly improve the theory and the practice of modeling, designing, and implementing computer systems... The standpoint of this analysis is the role of agent-based software in solving complex, real-world problems. In particular, it will be argued that the development of robust and scalable software systems requires autonomous agents that can complete their objectives while situated in a dynamic and uncertain environment, that can engage in rich, high-level social interactions, and that can operate within flexible organizational structures."

• Matt Weisfeld, The Object-Oriented Thought Process, Third Edition, Addison-Wesley, 2009, 330pp.

  Abstract: This book is designed to help newcomers to object-oriented programming (OOP) to learn guidelines for solid class design, to master the major concepts of inheritance, composition, interfaces, and abstract classes, and to create components to use in building more sophisticated systems. The author motivates and illustrates his points by taking readers step by step through a real-world application -- a simple e-commerce application framework using Java interfaces and abstract classes.

II.B Introduction to Java

• Oracle (previously Sun Microsystems) maintains a site called The Java Tutorials that provides a practical guide for programmers with pointers to hundreds of complete working examples and "trails" (groups of lessons) on various topics (e.g., getting started, learning Java, essential Java classes, user interfaces, writing applets, creating a GUI, etc.).

• Oracle (previously Sun Microsystems) maintains a site called Java SE Documentation at a Glance.

• Oracle (previously Sun Microsystems) maintains a site titled New to Java Programming Center that provides a collection of links to Java resources (articles, tutorials, online books, and software downloads) to help people new to Java to find what they need to start writing applications. The resources are divided into three categories: (1) Java Platform Overview; (2) Getting Started (How to Set Up the Java Platform on a PC); (3) Step-by-Step Programming (Learning the Basics of the Java Programming Language).

• Robert Sedgewick and Kevin Wayne (Princeton University) maintain an on-line self-study guide/eBook for scientists and engineers called Introduction to Programming in Java. Covered topics include: elements of Java programming, functions and modular programming, object-oriented programming, and algorithms and data structures. The online site is a condensed version of their Addison-Wesley textbook (same title).

• John T. Murphy 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.

• O'Reilly maintains a site called Java Development and Resources, with links to Java books, videos, and online courses.

Other source materials related to agent-oriented programming

III. Getting Acquainted with Repast

III.A Background Materials

• Nick Collier (Verizon), Repast: An Extensible Framework for Agent Simulation (pdf,36KB), Working Paper, Social Science Research Computing, University of Chicago, 2001. Note: While dated, this working paper provides interesting insight regarding the original developers' envisioned goals for RePast.

• Robert Tobias and Carole Hofmann (2004), Evaluation of Free Java-Libraries for Social-Scientific Agent Based Simulation (html,31pp), Journal of Artificial Societies and Social Simulation, Vol. 7, No. 1.

  Abstract: This paper uses a comprehensive set of criteria to compare four freely available Java-based programming libraries for support of social scientific agent-based computer simulation: Repast, Swarm, Quicksilver, and VSEit. The authors conclude: "...the weighted results show Repast(J) to win out over the other Java based programming libraries examined."

• People interested in Repast can freely subscribe to the Repast-interest Mailing List This list is for general discussion of, and help with, writing models with Repast and modeling issues in general.

III.B Downloadable Stand-Alone Repast Demos

• The latest release of Repast -- more generally, of all versions of Repast in the Repast Suite -- can be downloaded as freeware from the Repast GitHub Repository. These downloads include a number of stand-alone demonstration models 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.

IV. Programming with Repast

IV.A The Repast Software Framework

• The latest release of the Repast software framework (open source), together with documentation, tutorials, and demos, can be downloaded from the Repast GitHub Repository.

• Jakub Kielbasa has prepared a brief introductory document for programming a "ReLogo" agent-based modeling project in RePast using Groovy (pdf,1.1MB). Groovy is a high-level object oriented programming language on the Java platform, similar to Python. Groovy allows Java syntax. However, relative to Java, there is a reduction of scaffold coding that makes coding much simpler (and easier to debug). This document covers a variety of topics, including: (i) creating a ReLogo project; (ii) basics of agent methods; and (iii) experimentation and output for statistical analysis. Some elements may also be useful for use in the Java implementation of a RePast model.

IV.B Repast Development Environments

Note: Integrated Development Environments (IDEs) are programs that permit you to write, compile, run, and debug programs from within a single environment.

• Eclipse IDE

  • The Eclipse IDE is a powerful open-source Java IDE that can be used for Repast applications.

  • John T. Murphy prepared a brief tutorial, titled Eclipse Basics (html), that explains the primary steps needed to create a Java project in Eclipse and to work with it effectively.

• IntelliJ IDEA IDE

  • IntelliJ IDEA is a Java IDE developed and distributed by the software development company JetBrains. The June 2004 release IntelliJ IDEA 4.5 (code-named "Pallada") includes full support of Java Development Kit (JDK) 1.5. NOTE: IntelliJ IDEA is a commercial product (not free!).

• Netbeans IDE

  • Oracle (previously Sun Microsystems) provides a freely available full-featured IDE for Java developers called the NetBeans IDE.

IV.C Other Repast Documentation and Tutorials

• Documentation and tutorials about Repast can be accessed at the Repast GitHub Repository.

IV.D Repast Demos and Applications (Open Source)

• Papers reporting on a variety of research projects implemented in Repast can be accessed at the Repast GitHub Repository/Papers

IV.E Design of Experiments

• Leigh Tesfatsion, "Introduction to Experimental Design: Basic Concepts and Terminology" (pdf,54KB).

Possible Repast Modeling Application Areas

• Summary Listing of Research Areas

• Agent-Based Computational Laboratories

• Automated Markets

• Business and Management

• Coupled Natural and Human Systems

• Economic Policy

• Electricity Markets

• Empirical Validation and Verification of Agent-Based Computational Models

• Evolution of Institutions and Social Norms

• Experiments with Real and Computational Agents

• Financial Economics

• Industrial Organization

• Labor Economics

• Learning and the Embodied Mind

• Macroeconomics

• Market Design

• Network Formation and Evolution

• Organizations

• Path-Dependence and Network Lock-In Effects

• Political Economy

• Technological Change and Development Economics

Copyright © Leigh Tesfatsion. All Rights Reserved.