Known Issues

If NetLogo malfunctions, please send us a bug report. See the "Contact Us" section for instructions.

Known bugs (all systems)

• Integers in NetLogo must lie in the range -2147483648 to 2147483647; if you exceed this range, instead of a runtime error occurring, you get incorrect results
• Out-of-memory conditions are not handled gracefully
• The stop and report commands do not work properly if used inside without-interruption (we are already working on fixing this)
• The uphill and downhill reporters sometimes return incorrect answers for turtles which are standing on patch boundaries; we are already working on fixing this, but in the meantime you may wish to use uphill4 and downhill4 instead
• If you use "Export World" to suspend a model run and then resume it later with "Import World", this may change the outcome of the model run if your model involves turtles dying and new turtles being born, because the export/import may change what who numbers get assigned to new turtles (we are already working on fixing this)
• "Export World" does not include the contents of plots (we are already working on fixing this)
• Extensions that require additional external jars don't work from models saved as applets (we are already working on fixing this)
• The 3D View doesn't work on some graphics configurations; on others the 3D View works but 3D full screen mode doesn't
• A bug in Java causes patch colors imported using import-pcolors to be brighter than the original if the original image has a grayscale palette. To work around this issue, convert the image file to an RGB palette.

Windows-only bugs

• The "User Manual" item on the Help menu does not work on every machine (Windows 98 and ME are most likely to be affected, newer Windows versions less so)
• Drawing and then erasing a line in the drawing may not erase every pixel exactly.
• On some laptops, the Procedures and Info tabs may become garbled when you scroll them. To avoid this bug, reduce the size of the NetLogo window and/or reduce the color depth of your monitor (e.g. change from 32-bit to 16- or 8-bit color). This is a bug in Java itself, not in NetLogo per se. For technical details on the bug, see http://developer.java.sun.com/developer/bugParade/bugs/4763448.html (free registration required). NetLogo users are encouraged to visit that site and vote for Sun to fix this bug.

Macintosh-only bugs

• On Mac OS X 10.4 only, the "Copy View" and "Copy Interface" items may not work: the resulting image is distorted. The workaround is to use the "Export View" and "Export Interface" items instead. This issue will go away if you use Software Update to get the latest Java from Apple.
• When opening a model from the Finder (by double-clicking on it, or dragging it onto the NetLogo icon), if NetLogo is not already running, then the model may or may not open; the bug is intermittent. (If NetLogo is already running, the model always opens.)
• On versions of Mac OS X prior to 10.4, it is possible for NetLogo's menus to get confused so that the "Quit" item does not work. If this happens, you can quit NetLogo by pressing the red close button on the left end of the NetLogo's title bar.
• On Mac OS X 10.2 only, the "User Manual" item on the Help menu will sometimes launch a web browser other than your default browser
• On Mac OS X 10.2 only, opening the Models Library can trigger an error if you have malformed fonts installed. If this happens you should determine which fonts in /System/Library/Fonts and other font directories are causing the problem and remove them.

Linux/UNIX-only bugs

• User Manual always opens in Mozilla, not your default browser. One possible workaround is to bookmark the file docs/index.html in your favorite browser. Another workaround is to make a symlink that's called "mozilla" (that's the command name NetLogo tries to run), but actually runs a different browser.
• We have discovered a problem on Linux where the "exp" reporter sometimes returns a slightly different answer (differing only in the last decimal place) for the same input. According to an engineer at Sun, this should only happen on Linux kernel versions 2.4.19 and earlier, but we have observed the problem on more recent kernel versions. We assume the problem is Linux-specific and does not happen on other Unix-based systems. We are not sure if the problem ever occurs in practice during actual NetLogo model runs, or only occurs in the context of our testing regimen. The bug in the Sun's Java VM, and not in NetLogo itself. We hope that only the "exp" reporter is affected, but we can't be entirely certain of this. NetLogo users are encouraged to visit http://developer.java.sun.com/developer/bugParade/bugs/5023712.html (free registration required) and vote for Sun to fix this bug.
• If NetLogo cannot find the font Lucida, menus will be illegible. This has been known to happen on Fedora Core 3, after upgrading packages. Restarting the X Font Server (xfs) has resolved the problem in all reported cases.
• Sun's 1.5.0 Java runtime has display problems with GTK 2.0 and NetLogo. Issues may include windows not updating properly, interface elements being strangely sized, menus being cut-off at the bottom, and weird characters appearing on the view. To avoid these issues, you can use Sun's j2sdk1.4.2_10. Also, the JDK6 beta release from Sun does quite well.

Known issues with computer HubNet

See the HubNet Guide for a list of known issues with computer HubNet.

Unimplemented StarLogoT primitives

The following StarLogoT primitives are not available in NetLogo. (Note that many StarLogoT primitives, such as count-turtles-with, are intentionally not included in this list because NetLogo allows for the same functionality with the new agentset syntax.)

• maxint, minint, maxnum, minnum
• import-turtles, import-patches, import-turtles-and-patches (note that NetLogo adds import-world, though)
• bit, bitand, bitneg, bitor, bitset, bitstring, bitxor, make-bitarray, rotate-left, rotate-right, shift-left, shift-right
• camera-brightness, camera-click, camera-init, camera-set-brightness
• netlogo-directory, project-directory, project-name, project-pathname, save-project