Programming

Agent (Turtles) - a representation of creatures, particles or other objects that follow simple rules.

Agent Variables - Each agent has a unique instance of the variable - internally, every agent has an instance of the agent variable. Each agent has the ability to read and change its unique instance. Changing the agent variable of one agent does not change the value of the same agent variable for all the other agents.

Behavior - The rules and actions that an agent performs.

Boolean - a decision with only two possible answers: yes or no, true or false, etc.. Usually used by an If statement: If _________ is True, then do _________.

Calling - reading and performing an action or procedure (A plankton calls the slow move procedure.)

Cycle - A cycle ends after every agent has gone through their own run procedures and then starts over.

Declaration - telling an agent or the world that they have a trait. Telling an agent or the world that they have a trait creates that trait which can then be set, changed, read, etc..

Duration - the period of time in which an event takes place. In modeling, we usually use "The duration of the model" to mean the period of time in which the model is running.

Forever - A block in Starlogo TNG. This block puts a button in Spaceland, and contains code that is run when the button is clicked.

Global - See Shared Variables.

Heading - a pre-made variable that says what direction a turtle is facing.

Ifelse - an if statement which gives an option for when the statement is False. (Also see Boolean.)

Inc. - Increase or Increment; changes a number variable by a given amount.

Language - Refers to various types of programming, i.e. Netlogo, Starlogo, Java.

Moore - see neighborhoods

Neighborhoods - A Moore Neighborhood consists of the surrounding eight squares (including diagonals), while the Von Neumann neighborhood includes only the four; front, back and sides.

Nesting - a command within a command. Think of Russian dolls; you have a large, hollow doll. Within that doll is a slightly smaller, similar or identical doll. Within that is another, and so on.

Procedure - a list of actions that a turtle performs; procedures are used to divide up code so that it is easier to read and understand. (Also see Algorithm.)

Runtime - is a state of the model(/game/program). When the model is running, it is in runtime. The Runtime page of Starlogo TNG is meant to contain the code that a turtle calls while the model is running.

Setup - A standard name for a procedure used to set up your experiment, game, model or program.

Shared (formerly Global) Variables: - All agents share and reference only one instance of the variable. All agents have the ability to read and change this one instance.

Slider - Is connected to a shared variable so that the number that variable contains can me changed from Spaceland.

Spaceland - Is the graphical interface where you can watch the model run.

Subprocedure - a procedure that is part of another procedure; nested procedures; a procedure called by another procedure.

Turtles - See Agents.

Variable - a trait of a turtle or of the world (see Shared Variables and Agent Variables).

Von Neumann - see neighborhoods