1. Simulation Properties and Agent Attributes
Scalable Game Design Project
AgentSheets®
Thought Amplifier
Funded in part by

2. Overview Discussion What are Simulation Properties?
What are Agent Attributes?
When MUST you use each?
When is it “designer’s choice”?
Naming conventions
Examples
Exercises
Challenge
Add notes as needed

3. Discussion What are Simulation Properties? What are Agent Attributes?
When MUST you use each?
When is it “designer’s choice”?
Add notes as needed

4. What is a Simulation Property?
Information common to, accessible to, and shareable by all agents in a project
In programming languages, often referred to as a “global variable”
Analogy: number of cars in a parking lot
Each driver affects the number of cars by entering/exiting
Every driver can “see” the number of cars
Add notes as needed

5. What is an Agent Attribute?
Information unique to each agent
In programming languages, often referred to as a “local variable”
Accessible for write/update only by the agent possessing the attribute
Visible for read only by agents immediately surrounding the agent possessing the attribute
Analogy: mileage of each car in a lot
Only the driver can change the mileage on a car
Nearby drivers can “see” the mileage of neighboring cars (by looking through the driver’s window)
Add notes as needed

6. When Must You Use a Simulation Property?
If multiple agents must be able to “see” and/or update the information
Example: In a Sokoban project, Palette agents must report (add to a counter) if a box is resting atop them.
Example: Contagion model requires maintaining a statistic of the number of infections that occur.
Example: in wildfire model, trees are more likely to catch fire based on current wind direction
Add notes as needed

7. When Must You Use an AgentAttribute?
If each agent has information unique to that agent
Example: In a model in which one agent seeks another using hill-climbing, a medium agent (e.g., a floor agent) maintains the attribute on which hill-climbing is based
In a game in which a certain number of collisions (“hits”) are required to remove an agent
Example: In a contagion model, when a person agent gets sick, it remains sick for a certain number of simulation cycles before recovering
Add notes as needed

8. When Can You Choose the Variable Type?
If none of the “must” conditions apply!
Example: A clock agent maintains the elapsed time of simulation
Example: A monitor agent maintains the current number of sick persons in a contagion model
Add notes as needed

9. Naming Conventions All variables must begin with a letter
Names may contain letters, numbers, and the underscore character (“_”)
Variables are case-insensitive when used in conditions and actions
When referring to simulation property in a condition or action, the character must precede the name
Spaces should not be used!
Simulation property examples:
@trees, @maximum_count, @steps_36
Agent attribute examples:
contacts, max_width, row_number, years_2_grow
Add notes as needed

10. Exercises #1
Choose which variable type to use and justify. Is that type required or a “designer’s choice”?
In a Frogger game, the total number of trucks generated
In a Frogger game, the maximum number of trucks generated by a single tunnel
In a Frogger game, the number of moves made by the frog
In a Frogger game, the number of frog lives remaining
In a Spacer Invaders game, the number of “hits” received by the mother ship
In a Pacman game, the number of pellets eaten by the pacman
Add notes as needed

11. Exercises #2
Choose which variable type to use and justify. Is that type required or a “designer’s choice”?
In a predator-prey model, the number of prey eaten
In a predator-prey model, the currenthunger level of the predator
In a forest fire model, the number of burning trees
In a forest fire model, the number of unburned trees
In a forest fire model the maximum time any tree has burned
In a contagion model, the number of sick persons
In a contagion model, the number of persons who died
Add notes as needed

12. Implement one or more of the above exercises
Challenge
Implement one or more of the above exercises
In the comments section of the method(s) in your example document the variable(s) used and the reasoning for selecting that approach
Add notes as needed