
The GAP 4 Package `AtlasRep'
============================

Description
-----------

This is Version 1.2 of the package `AtlasRep' written for GAP 4,
whose aim is to provide an interface between GAP
and the Atlas of Group Representations,
a database that comprises representations of many almost simple groups
and information about their maximal subgroups.
This database is available independent of GAP at

    http://web.mat.bham.ac.uk/atlas/v2.0.

The AtlasRep package consists of this database and a GAP interface.
The latter allows the user to get an overview of the database,
and to access the data in GAP format.

There is a manual in the subdirectory `doc' written in plain TeX.
It describes the available functions in detail.
The subdirectory `htm' contains an HTML version of this manual.

Up to now, the package has been developed and tested only on Linux,
it may or may not work on other platforms.
Two possible problems are the use of a perl script (or alternatively wget)
for internet access
and the use of filenames that do not obey the ``8+3'' restriction.

The package requires GAP 4.4 (or a newer version of GAP).


Authors
-------

The data files of the ATLAS of Group Representations have been prepared by
Robert Wilson, Peter Walsh, Jonathan Tripp, Ibrahim Suleiman, Stephen Rogers,
Richard Parker, Simon Norton, Steve Linton, and John Bray
(in reverse alphabetical order).

The GAP interface was written by Thomas Breuer.


Feedback
--------

If you have used the `AtlasRep' package to solve a problem,
please let us know by sending an email to 

          Robert A. Wilson  (R.A.Wilson@bham.ac.uk) or
          Thomas Breuer     (sam@math.rwth-aachen.de)

about it.

Any comments about the package are very welcome.
If you have found important features missing or if there is a bug,
let us know and we will try to address it in the next version of the package.
Messages concerning the data of the package should be sent to Robert Wilson,
messages concerning the GAP interface to Thomas Breuer.


Contents
--------

With this version you should have obtained this README file
and an archive file containing the GAP interface
in the following files and directories:

        datagens        the directory for files with generators
        dataword        the directory for files with straight line programs
        doc             the directory with the package manual
        etc             the directory with scripts called by the GAP programs
        gap             the directory with the GAP code
        htm             the directory with the manual in HTML format
        init.g          the file for initializing the package
        read.g          the file for reading in the package        
        tst             the directory with some test files

The archive does *NOT* contain the database part of the package;
the GAP interface accesses the data on demand via the internet.


Unpacking
---------

You may have got the GAP interface of the package as
a zoo archive (filename ends with .zoo)
or a compressed tar archive (filename ends with .tar.gz).
In each case, use the appropriate command on your system to unpack
the archive.

On UNIX systems the zoo archive may be unpacked by

    zoo x atlasrep1r2p1.zoo

which will unpack the archive into a directory `atlasrep' in the
current directory. 

On UNIX systems the compressed tar archive may be unpacked by

    tar xzf atlasrep1r2p1.tar.gz

or, if tar on your system does not understand the option z, by

    gunzip atlasrep1r2p1.tar.gz
    tar xf atlasrep1r2p1.tar

which will in each case unpack the code into a directory `atlasrep'
in the current directory.

If your system does not have a zoo programme, you can pick up the
C-code for unzoo from the GAP web page and compile it on your system.
For this your system needs to have a C-compiler.
unzoo can be used to unpack the zoo archive, as follows:

    unzoo -x atlasrep1r2p1.zoo

unpacks the archive into a directory `atlasrep' in the current directory.


Installation
------------

Installation of the AtlasRep package means unpacking the archive file
in an appropriate directory.

For the two ways of installing GAP packages in general,
see the sections "Installing GAP Packages" and
"Installing a GAP Package in your home directory"
in the GAP Reference Manual.

Special configuration issues of the AtlasRep package are described
in the following sections of the package manual.

    "Local or Remote Installation of the AtlasRep Package",
    "Installing the AtlasRep Package",
    "Maintaining the Local Data of the AtlasRep Package", and
    "User Parameters for the AtlasRep Package".

They might be of interest after unpacking the archive.

Once you have successfully installed the AtlasRep package,
start GAP (possibly using the command line option -l) and type

gap> LoadPackage( "atlasrep" );
true
gap>

at the GAP prompt.
Then the functions of the package are available in the current session.

For Windows users, neither perl nor wget seem to be available in a standard
operating system.
Information about wget for Windows (and executables) can be found at

    http://wget.sunsite.dk


News
----

The internet homepage of the AtlasRep package is

    http://www.math.rwth-aachen.de/~Thomas.Breuer/atlasrep

Besides package archives and introductory package information, it provides

- the current table of contents (the file `gap/atlasprm.g'),
  which is needed for those who use `wget' for accessing data files
  (see the section "User Parameters for the AtlasRep Package"
  of the package manual,

- the list of changes of server files
  (cf. section "Maintaining the Local Data of the AtlasRep Package"
  of the package manual, and

- an overview of the data available via the {\GAP} interface to the
  ATLAS of Group Representations,
  similar to the information shown by the function `DisplayAtlasInfo'
  of the package;
  more details can be found on the home page of the {\ATLAS} (see above).


