# ACE

Version 5.3
Released 2020-02-12

This project is maintained by Greg Gamble, Max Horn

# The ACE package

The ACE package provides functions associated with Todd-Coxeter coset enumeration by interfacing with the Advanced Coset Enumerator (ACE),

ACE coset enumerator (C) 1995-2001 by George Havas and Colin Ramsay http://staff.itee.uq.edu.au/havas

from within GAP 4.

The GAP interface (package) has been written by Alexander Hulpke and Greg Gamble. In order to install the ACE package you must get the archive file e.g. ace-XXX.tar.gz, for some version number XXX, (which includes the C source code of Havas and Ramsay).

The ACE package provides a mechanism to replace GAP’s usual Todd-Coxeter coset enumerator by ACE, so that functions that behind the scenes use coset enumeration will use the ACE enumerator. The ACE enumerator may also be used explicitly; both non-interactively and interactively. However the package is used, a plethora of options and strategies are available to assist the user in avoiding incomplete coset enumerations.

You can download ace-XXX.tar.gz (where XXX is the package version number) from the home page for the ACE package

https://gap-packages.github.io/ace/

or via the GAP web site

https://www.gap-system.org/Packages/ace.html

If you prefer .zip or tar.bz2 to tar.gz archives, substitute the appropriate suffix in the above paths.

Since the ACE package interfaces to an external binary, it is only usable in an environment that supports compiling of the binary, e.g. a UNIX or a UNIX-like environment.

## Installing the ACE package

To install the ACE package, move the file ace-XXX.tar.gz into the pkg directory in which you plan to install ACE. Usually, this will be the directory pkg in the hierarchy of your version of GAP 4. (However, it is also possible to keep an additional pkg directory in your private directories, see section “ref:Installing GAP Packages” of the GAP 4 reference manual for details on how to do this.)

Then unpack ace-XXX.tar.gz, which in most Linux environments can be done by

tar zxf ace-XXX.tar.gz


Go to the newly created ace directory and call configure <path> where

is the path to the GAP home directory. So for example if you install the package in the main pkg directory call ./configure ../.. In fact ../.. is the default path. So, if this is correct, you may omit it. This will fetch the architecture type for which GAP has been compiled last and create a Makefile. Now simply call make to compile the binary and to install it in the appropriate place. Note that the current version of the configuration process only sets up directory paths. If you need a different compiler or different compiler options, you need to edit src/Makefile prior to calling make yourself. If you use this installation of GAP on different hardware platforms you will have to compile the binary for each platform separately. This is done by calling configure and make for the package anew immediately after compiling GAP itself for the respective architecture. If your version of GAP is already compiled (and has last been compiled on the same architecture) you do not need to compile GAP again, it is sufficient to call the configure script in the GAP home directory. That's it. Now start GAP and type LoadPackage("ace"); The ACE banner should appear on the screen. For details on how to use the ACE package see the package documentation in the doc subdirectory (view either manual.dvi via xdvi or manual.ps via ghostview or manual.pdf via a PDF viewer), which gives information on how to use ACE from within GAP. The ACE user manual (ace3001.ps or ace3001.pdf) in the standalone-doc directory, explains how to use the ACE binary (i.e. the C program that is interfaced with by the package from within GAP) as a stand-alone. The src subdirectory contains a copy of the C source code for ACE. The only modification are those listed in src/CHANGES. In particular, the the following bug was fixed on 25 February, 2001. A bug was discovered in ACE 3.000 on 22 December, 2000 that was particularly manifested by the Linux gcc compilers listed below. The bug was reported with fix by Volker Gebhardt (thanks!) and caused a segmentation fault when ACE output coset representatives. The fix is incorporated in ACE 3.001 which we now use. ACE has been compiled successfully with the following C compiler: gcc version 4.8.4 (Ubuntu 4.8.4-2ubuntu1~14.04.1) and is presumed to compile with any modern version of C compiler. If you encounter problems with the ACE binary, please contact one of the C code authors: George Havas <havas@itee.uq.edu.au> or Colin Ramsay <cram@itee.uq.edu.au>. If you encounter problems at the GAP level, please submit an issue to <https://github.com/gap-packages/ace/issues> When sending a bug report, remember we will need to be able to reproduce the problem; so please include: * The version of GAP you are using; either look at the header when you start up GAP, or at the gap> prompt type: VERSION; * The operating system you are using e.g. Linux, macOS, Windows, ... * The compiler you used to compile ACE and the options you used. Type: gcc -v or: cc -version, and look in src/Makefile for the value of CC to find out. * A script, either in GAP or standalone ACE, that demonstrates the bug, along with a description of why it's a bug (e.g. by adding comments to the script - recall, comments, both in GAP or standalone ACE, begin with a #).