Frequently Asked Questions



1. Downloading Starlogo

I downloaded StarLogo for Windows and it won't run.

Did you download the StarLogo with Java or without Java? If without, make sure you've got Sun's Java JRE 1.4.2 installed. If with, please send us some email at bug-starlogo@media.mit.edu and we'll try to help you out.

I downloaded StarLogo 'for any computer' and I can't figure out how to make it run.

This StarLogo download requires Sun's Java JRE 1.4.2 to be installed on your machine. Once you've done that, on Windows, you can run the starlogo.bat file from a DOS shell, or by double-clicking its icon in the Windows Explorer. On Unix, there is a shell script called run-starlogo.sh which you can use to start StarLogo. On MacOSX, please download the MacOSX-specific version of StarLogo instead of the one 'for any computer'.

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2. Running Projects

Why doesn't my project work in the new version of StarLogo (version 2.0+)?

There are two possible reasons for your old project not working in the new version of StarLogo. The first reason is that the command for pressing buttons from the command center has changed. Before you only had to enter the name of the button. For example, if your button was named "go", you simply had to enter "gobutton"; however, in the new version you will have to enter "startgobutton". In other words, you have to append the word "start" to the beginning of code calling for pressing buttons. This may have to be done manually in old projects and then resaved.

The second reason your project may not work in the new version of StarLogo is that version 2.0 implements tighter error checking for code in the command center. One of the most common errors is the code: "(3 +5)". This error used to be ignored in the old StarLogo. However, in the new version, this error will stop a project from compiling properly. Make sure your old code is free from these errors.

Why doesn't the new project I downloaded work on my StarLogo?

If you have StarLogo version 1.2.2, it may not be able to compensate for some of the new features in StarLogo version 2.0, and this may be what is causing you errors in the new project. Get the newest version of StarLogo at the download site.

Why doesn't project X from my old MacStarLogo run anymore?

StarLogo is similar in many ways to MacStarLogo. However, it stores projects in its own unique format. In addition, there are language differences between StarLogo and MacStarLogo that prevent projects from being saved in one program and run by the other. If you would like to translate a MacStarLogo project for use in StarLogo, open it in StarLogo (or a text editor). Some changes will be necessary before it will run. Consult the StarLogo documentation to find out more about how to create projects in StarLogo. If you are having difficulty translating your projects into StarLogo, you can email bug-starlogo@media.mit.edu with questions.

Why can't I use templates in StarLogo when running on Mac/Unix?

Our template code is too naive and can not read files with macintosh or Unix carriage returns. Sorry that we can't support this on other platforms.

I would like to use sound with my projects. Where can I find a sample project which demonstrates how to do this?

Sounds have been disabled in this release of StarLogo due to the non-standard implementation of Java on different operating systems.

How can I run a StarLogo project on a web page?

When you are ready to save your desired project, choose "Save Project as Web Page" from the File menu. You will first be prompted to save the StarLogo version of this project (a .slogo file) and then to choose a name for the .html file. To allow the applet to be run over the web, place a copy of this starlogo.jar, your project (.slogo) file, and your web page (.html) file all in the same directory, and then load the .html file into your browser. On a Mac, the starlogo.jar file can be found in the StarLogo folder. Windows users can find it inside the Internal StarLogo files folder. We have confirmed that this applet will run on PCs using Internet Explorer and Netscape. If you don't have the Java plug-in for Netscape, your browser will prompt you to download it when you try to load the applet. If you're using a Mac, you will need to use Max OS X's Safari and Java 1.4.2 or later.

What are valid names for buttons?

When you bring up a Button Dialog to create a new button, the "Name" field can be filled with any string of characters. If you have spaces (" ") in this name, they are converted to the dash character ("-") internally. This has two implications. First, it means that you can allow a procedure to call a button by prepending the word "start" to the button name and stop a button by prepending the word "stop" to the button name. For example,

to go
myfirstbutton ;the "Name" field of this button contains the string
"myfirstbutton"
startmy-second-button ;the "Name" field of this button contains the string
"my second button"
stopmyfirstbutton
end

One more thing. You naming conflicts may occur in the internal code if any of your procedure names begin with "start". Avoid naming procedures in this manner.

How do I resize the graphics canvas?

If you click in the white area of the StarLogo window, and then drag your mouse over the black graphics canvas, the canvas should become selected (little black squares will appear at the corners, and some sizing information will appear on the grey toolbar at the top). You can use the black squares to resize the canvas (click and drag), and you use the slider which appears in the toolbar to change the size of the patches.

Why do I get an error that the observer doesn't know how to run my button?

In the new version, you need to put start or stop in front of the button name.
Example: To start or stop a button named Go: startGo or stopGo.

What is the Edit/Calibrate Graphics menu item and what can it do for me?

There are many ways to use Java to draw to the screen, and some ofthem are faster than others. We've included three different schemes in StarLogo because unfortunately, there's no 'fastest' drawing scheme for all computers. Calibrate Graphics tests each of the drawing schemes with various numbers of turtles to find out which one runs fastest on your computer. It then saves this information so it can be used for each StarLogo session on that computer. You'll only need to run this once when you put StarLogo on a new computer, and then the graphics will run as fast as possible. If you don't run Calibrate Graphics, StarLogo will make a guess at which drawing scheme should work best (based on what works best here at MIT) which should give you decent performance.


3. Macintosh Information

I have a Macintosh. Which version should I use?

StarLogo requires Mac OS X 10.2.6 or higher, while MacStarLogo Classic will run on a Mac IIfx or better running Mac OS 7.5 or higher and with at least 256 colors. The features of the two programs are slightly different, so you might want to try StarLogo before making a final
decision. If you have a recent mac running Mac OS 10.2.6 or higher you most likely want to run StarLogo 2.1. For more information, see the Notes section.

I still want to use MacStarLogo.  Where can I find information on it?

The MacStarLogo website has moved to http://education.mit.edu/macstarlogo

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4. Other

I've read about several other StarLogo projects from Mitchel Resnick's book Turtles, Termites, and Traffic Jams but I can't get any of the code in his book to run in StarLogo. What should I do?

If you are planning on using code from Professor Resnick's book, it will require several modifications in order to run under StarLogo. In particular, you will need to separate his procedures into separate observer and turtle procedures, in much the same way as you would have to if you were porting a project from MacStarLogo to StarLogo. Also, the daemons (demons) in Professor Resnick's book no longer exist; they have been replaced by forever buttons. Consult the StarLogo documentation to find out more about how to create projects in StarLogo.

What other StarLogo-type programs exist and where can I find them?

StarLogoT has been developed at Tufts University and Northwestern University. StarLogoT was built on top of MIT's MacStarLogo, adding some new capabilities and interface features.

NetLogo is a multiplatform complexity modeling and simulation environment that shares many features with StarLogo.

Agentsheets is a commercial product that lets end-users build a wide range of applications that include interactive simulations, games, and intelligent web agents through a graphical user interface.

For more advanced research applications you can also check out Swarm, Ascape, and Repast.

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5. Known Bugs

Why does StarLogo sometimes freeze and give me the spinning beachball of death on my MacOSX computer?

MacOSX Java is engineered a bit differently than Windows Java. We're still working out all the kinks with our interactions with the AWT event thread in our Java code. As we fix bugs with this, we'll make patches available to users.


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