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This is a page on GAP 3, which is still available, but no longer supported. The present version is GAP 4  (See  Status of GAP 3).

GAP 3 Share Package "matrix"

The matrix package

Share package since release 3.4, April 1997, communicated by Akos Seress (1958-2013).
(The package "matrix" has superseded the GAP 3 share package "smash" as well as the GAP 3 package "classic" by Frank Celler and Charles R. Leedham-Green.)
The package "matrix" has not yet been transferred to or replaced in GAP 4. You can use it only in GAP 3.


Frank Celler, Eamonn O'Brien, and Anthony Pye.


Language: GAP 3
Operating system: Any
Current version: 1.0 (in the 3.4.4 distribution)


The aim of the matrix package is to provide integrated and comprehensive access to a collection of algorithms, developed primarily over the past decade, for investigating the structure of matrix groups defined over finite fields. We sought to design a package which provides easy access to existing algorithms and implementations, and which both allows new algorithms to be developed easily using existing components, and to update existing ones readily.

Some of the facilities provided are necessarily limited, both on theoretical and practical grounds; others are experimental and developmental in nature; we welcome criticism of their performance. One motivation for its release is to encourage input from others.

The development and organisation of this package was carried out in Aachen by Frank Celler, Eamonn O'Brien and Anthony Pye.

In addition to the new material, this package combines, updates, and replaces material from various contributing sources. These include:

  1. Classic package - originally developed by Celler;
  2. Smash package - originally developed by Holt, Leedham-Green, O'Brien, and Rees;
  3. Niemeyer/Praeger classical recognition algorithm - originally developed by Niemeyer;
  4. Recursive code - originally developed by Pye.

As part of the preparation of this package, much of the contributed code was revised (sometimes significantly) and streamlined, in cooperation with the original developers.


A Matrix manual is given in chapter 67 of the GAP 3 manual.

Contact address

Comments and criticisms are welcome and should be directed to:

Eamonn O'Brien
Department of Mathematics
University of Auckland
Auckland, Private Bag 92019
New Zealand


Frank Celler
Lehrstuhl D für Mathematik
RWTH Aachen
Pontdriesch 14-16
52062 Aachen

Eamonn O'Brien
Department of Mathematics
University of Auckland
Auckland, Private Bag 92019
New Zealand

Anthony Pye
School of Mathematical Sciences
Queen Mary, University of London
London, E1 4NS