How to use the GUI

A user can interact with a non-batch Repast simulation through the gui. The gui allows the user to start, stop, pause, setup, and exit a simulation through the toolbar. The table below lists the toolbar buttons and their functions.

Start Multi-Run	Start	Step	Initialize	Stop	Pause	Setup	Load Model	View Settings	Exit

1. Start Multi-Run: The start multi-run button starts a batch run of a simulation. See How to Use the Multi-Run for more details.
2. Start: The start button starts the simulation when it is paused or has not yet been started, iterating through the scheduled behavior.
3. Step: The step button starts the simulation when it is paused or has not yet been started, iterating through a single iteration the scheduled behavior.
4. Initialize: The initialize button starts the simulation but pauses before iterating any scheduled behavior. Only the initializing code is executed in this case.
5. Stop: The stop button stops the simulation.
6. Pause: The pause button pauses the simulation.
7. Setup: The setup button "sets up" the simulation by executing the user defined setup code.
8. Load Model: The load model button pops up a dialog allowing the user to specify a model to load.
9. View Settings: The view settings button will display the various model settings panel if it is hidden or destroyed.
10. Exit: The exit button will shutdown the simulation and exit.

To run a simulation you would click either the start, step or initialize buttons. If you click the initialize button, you would then click step or start. When you want to stop the simulation and then run it again, you click stop and then the setup button.

In addition, if the model has followed the get/set method pattern (see How to Build a Model and How to use Parameters and Parameter Files) the user will also be able to see and set the initial parameters of a simulation. The initial parameters will appear in the settings window on the tab entitled "Parameters" into which the user can see the default starting parameters and enter new ones.

Also in the settings window are the Custom Actions tab and the Repast Actions tab. The Custom Actions tab will contain any sliders, buttons, or checkboxes that the simulation author has defined. You can interact with the model while it is running through these sliders, buttons, and checkboxes.

The Repast Actions tab looks like:

• The first two buttons allow you to make a movie or take a snapshot. Clicking on one of these buttons will bring up a dialog containing further information and choices.
• The third button will bring up a dialog for creating an sequence chart. (This functionality is provisional at this time.)
• The "In Alpha Order" check box controls the order of the parameters in the parameters tab. If it is checked the parameters will appear in alphabetical order. Otherwise they will appear in the order they are defined in the model.
• The "Stdout to Console" check box determines if standard output (output from "System.out.println") will be captured by the Repast console.
• The "Stderr to Console" check box determines if standard error (output from "System.err.println") will be captured by the Repast console.
• The "RngSeed in Defaults" checkbox determines whether the current random number seed will be included as a default value either when written to a file or set as the current default.
• "Update Probes" determines whether or not any probed objects have their displayed properties updated in real-time or not.
• "Show custom charts" determines whether or not any custom charts created for this model using the "create / edit charts" button are automatically created and displayed when this model is run.
• The "Set As Default" button will set the current parameters as the default until Repast is exited. This means that whenever the setup button is pressed these new defaults will be used rather the initial parameters.
• The "Write Parameters" button will write the current parameters to a file so that can be loaded later.
• The "About" button displays a typical about dialog giving some further information about Repast.

A user may also probe objects in the simulation provided those objects implement the get/set method pattern and whose displays are added to the DisplaySurface as probeables (see How to Create Displays). To probe an object, pause the simulation, and left click on the object in the display. The probeable state of all the objects underneath the cursor should appear in windows similar to the "Parameters" tab in the settings window, and their properties can be set in the same way (i.e. changing the property and pressing enter).

Displaying a simulation can be one of the slowest parts of a simulation. Repast will not update the display if the display window is minimized, allowing for dynamic display updates. (Of course, these kind of updates can be set explicitly through a Schedule.) When the window is displayed again it will update in the usual manner.