Getting Started with Computer Simulations using NetLogo

1. Getting Started with Computer Simulations using NetLogo Teaching Contemporary Mathematics Conference January 25, 2013 Christine Belledin NC School of Science and Mathematics

2. Patches The Basics – Three Types Agents Turtles Links

3. Variable Definitions • Global variables • Agentset-specific variables • Setup Procedures • Clear variables • Use patches and turtles to create environment • Reset tick counter • Go Procedures • Define steps that are carries out on the agents at each tick • Use subroutines to add structure and clarity The Basics – Program Structure

4. NetLogo tutorials • My students work independently through the tutorials from the NetLogo website. • Tutorial 1: Students learn to use and explore existing models • Tutorial 2: Students learn to write command and modify existing models • Tutorial 3: Students build a simple NetLogo model • For less experiences students, you may want to complete Tutorial 3 together as a class. • Write a program as a class • Show students the Fire model from the NetLogo library. • Introduce modified problem (see next slide) and develop model • First homework: students make one addition/modification to our class model How I start NetLogo in my classroom

5. Suppose 30% of the wooded areas along the western edge of a region catch fire. There are 5 houses scattered throughout the area. In each step, if a neighbor of a patch is on fire, then the patch has a 50% chance of catching fire. Which house is most likely to burn? Modeling the Spread of a Fire

6. Step 1: Create the environment. • Turn patches green and brown • Randomly place houses • Set fires along western edge Step 2: Spread the fire. • Spread the fire through the green patches • Show a house burns by turning grey Step 3: Make improvements. • Identify problems in the simulation and address them • Try to have a stopping point for the simulation Step 4: Add in extras. • Allow user to input forest density, number of houses, etc. • Report the impact of the fire numerically or graphically Break the problem into steps

7. Start with the NetLogo tutorials from the NetLogo User Manual • Explore existing models from the Models Library • Look through the code of a few models and try to understand the logic • Try making modifications to existing models • Search the “Code Examples” section for simple examples of particular behaviors • Use the NetLogo dictionary to search for relevant commands • Check out the NetLogo Resources page for collections of models • Recommended book: Agent-Based and Individual-Based Modeling: A Practical Introduction (2011) by Steven F. Railsback and Volker Grimm Recommendations for learning more about NetLogoand ABM