Frequently Asked Questions

1. General Questions

   There is also a Russian version of this set of questions and the answers to them.

   • 1.1: What is GAP?
   • 1.2: What are the requirements for running GAP?
   • 1.3: Which skills do I need to use GAP?
   • 1.4: Who wrote GAP?
   • 1.5: How is the GAP Web Site organized?
   • 1.6: Where do I get your clothes, your Genome analysis software, your diving software, information about your irrigation projects?
   • 1.7: I wrote to you two days ago and I still have not got an answer.
   • 1.8: How do I cite GAP?
   • 1.9: What does all this information GAP prints at startup mean?

2. Obtaining GAP.

   • 2.1: Where can I download GAP?
   • 2.2: I cannot FTP that much data. Can I get a CD?
   • 2.3: Are there RPMS or DEB files for Linux?
   • 2.4: The files do not load properly in my browser.
   • 2.5: Can I obtain the algorithm and/or code for some function of GAP?
   • 2.6: How do I find my way through the GAP Library?

3. Installation

   • 3.1: How do I install GAP?
   • 3.2: Where do I find a manual?
   • 3.3: The HTML manual does not display properly in my browser.

4. Problems on Specific Hardware and Operating Systems (i.a. Windows and Macintosh)

   • 4.1: Some keys (arrow keys, ^) do not work on Windows.
   • 4.2: Cut and Paste do not work on Windows.
   • 4.3: The 'gap.bat' file does not start GAP.
   • 4.4: Windows complains Out of environment space.
   • 4.5: The zoo files are corrupt -- I cannot uncompress them
   • 4.6: I cannot compile GAP under OS X
   • 4.7: GAP on an AMD64 bit machine
   • 4.8: GAP on an Intel Itanium (IA64) machine

5. Usage hints

   • 5.1: How can I customize GAP ?
   • 5.2: How can I avoid excessive output?
   • 5.3: How can I stop excessive output?
   • 5.4: How can I save my GAP input and output?
   • 5.5: Can I run GAP remotely?
   • 5.6: Why should I use the "screen" program?
   • 5.7:Can I convert a file obtained from the GAP LogTo command into a Latex file?
   • 5.8: When I use time or Runtime() or the profiler to determine how long a piece of GAP code takes, the answers can vary significantly. Why is this?

6. Complaints

   • 6.1: I think I found a bug.
   • 6.2: My calculation does not finish (or GAP runs out of memory).
   • 6.3: My calculation with matrix groups is slow/runs out of memory.

7. Computing with GAP

   In addition to the list of frequently asked questions on computing with GAP given below,

   • David Joyner is collecting a list of frequently asked questions about Constructions of various mathematical objects in GAP with fully worked out GAP code answering them. This collection is specially recommended for newcomers to the system .
   • Alexander Hulpke has collected user questions (mostly from the GAP Forum) about mathematical applications of GAP together with the corresponding answers. See Some GAP Questions on his home page.
   • 7.1: How do I perform binary operations on the elements of a group?
   • 7.2: How do I represent my group in GAP?
   • 7.3: Does GAP support additive groups?
   • 7.4: In many algebra books the quaternion group is a group on 8 distinct symbols {i,j,k,1,-1,-i,-j,-k}. How can I make GAP use these elements?
   • 7.5: I have a finite presentation for a finite polycyclic group. When I tried to use PcGroupFpGroup() to convert it to a pc-group, I received an error message.
   • 7.6: How do I get the elements of my group?
   • 7.7: How do I get the subgroups of my group?
   • 7.8: Is GAP suited for studying combinatorial structures and finite permutation groups?
   • 7.9: How can one compute the Schur Multiplier of a finite group by GAP?
   • 7.10: How can one use GAP to check that given presentation is a nilpotent group of class 2 or not?
   • 7.11: How can one use GAP to "identify" a group?

8. Programming GAP

   • 8.1: Can I call GAP functions from another programme?
   • 8.2: Can I make a smaller version of GAP containing just the function(s) I need?
   • 8.3: Where is the GAP file editor? How do I save GAP programs?