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GAP Trouble

While we try to check the GAP system as rigorously as we can, such a large system will inevitably contain bugs. We regularly issue bugfixes and welcome bug reports. However since GAP is available free and the GAP authors work on the system as part of their research, we would like to ask you to make sure that the problem really is a bug before reporting it:

If your calculation runs into error, please check:

  • Do you have the most recent version of GAP installed?
  • If want to check if the bug that you are encountering may have been fixed already recently, have a look at the Release history.
  • What does the error message you get tell you? The error message might say that GAP ran out of memory or (‘No method found’) that the functionality is not available for the kind of objects you work with.

When reporting the error, please state:

  • What version of GAP and what computer you are using and possibly what compiler you used in installing GAP (some of this information will be contained in the banner you see when starting up GAP).
  • What is your input. (Please also include the definitions of your objects so that we can redo the calculation.)
  • What output do you get?

Before formulating a bug report it may be helpful to consult some additional advice given in How to Report Bugs Effectively.

The preferred way to submit bug reports is to use the GAP issue tracker on GitHub. Alternatively, you may send them to When using email, please don’t attach any log files, suggested patches etc. because this mailing list blocks attachments - put all the text into the body of email instead.