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<p><a id="X780A68B584B7F3DF" name="X780A68B584B7F3DF"></a></p>
<div class="ChapSects"><a href="chap1.html#X780A68B584B7F3DF">1 <span class="Heading">Introduction to the <strong class="pkg">AtlasRep</strong> Package</span></a>
<div class="ContSect"><span class="nocss"> </span><a href="chap1.html#X856D502978D8F801">1.1 <span class="Heading">An <strong class="pkg">ATLAS</strong> of Group Representations</span></a>
</div>
<div class="ContSect"><span class="nocss"> </span><a href="chap1.html#X8033B61682EE6A23">1.2 <span class="Heading">The GAP Interface to the <strong class="pkg">ATLAS</strong> of Group Representations</span></a>
</div>
<div class="ContSect"><span class="nocss"> </span><a href="chap1.html#X7DE8D7A88254E1DD">1.3 <span class="Heading">Web Services for the <strong class="pkg">AtlasRep</strong> Package</span></a>
</div>
<div class="ContSect"><span class="nocss"> </span><a href="chap1.html#X7F25ECBA7B675901">1.4 <span class="Heading">Installing the <strong class="pkg">AtlasRep</strong> Package</span></a>
</div>
<div class="ContSect"><span class="nocss"> </span><a href="chap1.html#X8313A28A849E489B">1.5 <span class="Heading">Loading the <strong class="pkg">AtlasRep</strong> Package</span></a>
</div>
<div class="ContSect"><span class="nocss"> </span><a href="chap1.html#X80D437A481096921">1.6 <span class="Heading">Maintaining the Local Data of the <strong class="pkg">AtlasRep</strong>
Package</span></a>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X7AC3EA317EDBDA0E">1.6-1 ReloadAtlasTableOfContents</a></span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X7E3E52D380C20363">1.6-2 StoreAtlasTableOfContents</a></span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X847A5AFD7B5D8570">1.6-3 ReplaceAtlasTableOfContents</a></span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X7E04B1C57C38DCB2">1.6-4 AtlasOfGroupRepresentationsTestTableOfContentsRemoteUpdates</a></span>
</div>
<div class="ContSect"><span class="nocss"> </span><a href="chap1.html#X7B04D2287CC44DE5">1.7 <span class="Heading">User Parameters for the <strong class="pkg">AtlasRep</strong> Package</span></a>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X7E1934D2780D108F">1.7-1 <span class="Heading">Local or Remote Access</span></a>
</span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X826B8F128277032E">1.7-2 <span class="Heading">Adding and Removing Servers</span></a>
</span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X7CB4D8F887BE5E84">1.7-3 <span class="Heading">Accessing Data Files with the <strong class="pkg">GAP</strong> Package <strong class="pkg">IO</strong>
or with <code class="file">wget</code></span></a>
</span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X7E0AC1127B4363E7">1.7-4 <span class="Heading">Compressed or Uncompressed Data Files</span></a>
</span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X83EE129B7A7650F2">1.7-5 <span class="Heading">Customizing <code class="code">DisplayAtlasInfo</code></span></a>
</span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X7FA485E479F6C3A0">1.7-6 <span class="Heading">Customizing the Access to Data Files</span></a>
</span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X866E1476853E42C2">1.7-7 <span class="Heading">Reading Large Matrices over Finite Fields</span></a>
</span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X80126409815DE5B6">1.7-8 AtlasOfGroupRepresentationsShowUserParameters</a></span>
</div>
<div class="ContSect"><span class="nocss"> </span><a href="chap1.html#X7FB64AD37D4620E6">1.8 <span class="Heading">Extending the <strong class="pkg">ATLAS</strong> Database</span></a>
</div>
<div class="ContSect"><span class="nocss"> </span><a href="chap1.html#X7B864EDC7CB211FD">1.9 <span class="Heading">What's New in <strong class="pkg">AtlasRep</strong>,
Compared to Older Versions?</span></a>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X86FE8602805AFA05">1.9-1 <span class="Heading">What's New in Version 1.4?</span></a>
</span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X83125C0278DBCEFB">1.9-2 <span class="Heading">What's New in Version 1.3.1?</span></a>
</span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X820A9F6E834B7972">1.9-3 <span class="Heading">What's New in Version 1.3?</span></a>
</span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X839B2C7A7B592F20">1.9-4 <span class="Heading">What's New in Version 1.2?</span></a>
</span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X8129F9467ED8C5B2">1.9-5 <span class="Heading">What's New in Version 1.1?</span></a>
</span>
</div>
<div class="ContSect"><span class="nocss"> </span><a href="chap1.html#X8207E35380A4BAFC">1.10 <span class="Heading">Acknowledgments</span></a>
</div>
</div>
<h3>1 <span class="Heading">Introduction to the <strong class="pkg">AtlasRep</strong> Package</span></h3>
<p>The aim of the <strong class="pkg">GAP</strong> 4 package <strong class="pkg">AtlasRep</strong> is to provide a link between <strong class="pkg">GAP</strong> and the "<strong class="pkg">ATLAS</strong> of Group Representations", a database that comprises representations of many almost simple groups and information about their maximal subgroups. This database has been available independent of <strong class="pkg">GAP</strong> at</p>
<p><span class="URL"><a href="http://brauer.maths.qmul.ac.uk/Atlas">http://brauer.maths.qmul.ac.uk/Atlas</a></span></p>
<p>The <strong class="pkg">AtlasRep</strong> package consists of this database (see Section <a href="chap1.html#X856D502978D8F801"><b>1.1</b></a>) and a <strong class="pkg">GAP</strong> interface (see Section <a href="chap1.html#X8033B61682EE6A23"><b>1.2</b></a>); the latter is extended by further information available via the internet (see Section <a href="chap1.html#X7DE8D7A88254E1DD"><b>1.3</b></a>).</p>
<p>Information about installing and customizing the package can be found in the sections <a href="chap1.html#X7F25ECBA7B675901"><b>1.4</b></a>, <a href="chap1.html#X8313A28A849E489B"><b>1.5</b></a>, and <a href="chap1.html#X80D437A481096921"><b>1.6</b></a>, <a href="chap1.html#X7B04D2287CC44DE5"><b>1.7</b></a>, <a href="chap1.html#X7FB64AD37D4620E6"><b>1.8</b></a>.</p>
<p>Finally, Section <a href="chap1.html#X7B864EDC7CB211FD"><b>1.9</b></a> lists the changes w.r.t. previous releases of the package, and Section <a href="chap1.html#X8207E35380A4BAFC"><b>1.10</b></a> acknowledges contributions of non-authors to the package.</p>
<p><a id="X856D502978D8F801" name="X856D502978D8F801"></a></p>
<h4>1.1 <span class="Heading">An <strong class="pkg">ATLAS</strong> of Group Representations</span></h4>
<p>The <strong class="pkg">ATLAS</strong> of Group Representations consists of matrices over various rings, permutations, and shell scripts encoding so-called black box programs (see <a href="chapBib.html#biBNic06">[Nic06]</a> and Section <a href="chap4.html#X7BE856BC785A9E8F"><b>4.2</b></a>). Many of these scripts are straight line programs (see <a href="chapBib.html#biBBSW01">[BSWW01]</a>, <a href="chapBib.html#biBSWW00">[SWW00]</a>, and <a href="../../../doc/htm/ref/CHAP035.htm#SECT008"><b>Reference: Straight Line Programs</b></a>) and straight line decisions (see Section <a href="chap4.html#X8121E9567A7137C9"><b>4.1</b></a>). These programs can be used to compute certain elements in a group G from its standard generators (see <a href="chapBib.html#biBWil96">[Wil96]</a> and <a href="../../../doc/htm/ref/CHAP068.htm#SECT010"><b>Reference: Standard Generators of Groups</b></a>), for example generators of maximal subgroups of G or representatives of conjugacy classes of G.</p>
<p>The <strong class="pkg">ATLAS</strong> of Group Representations has been prepared by Robert Wilson, Peter Walsh, Jonathan Tripp, Ibrahim Suleiman, Richard Parker, Simon Norton, Simon Nickerson, Steve Linton, John Bray, and Rachel Abbott (in reverse alphabetical order).</p>
<p>The information was computed and composed using computer algebra systems such as <strong class="pkg">MeatAxe</strong> (see <a href="chapBib.html#biBRin98">[Rin98]</a>), Magma (see <a href="chapBib.html#biBCP96">[CP96]</a>), and <strong class="pkg">GAP</strong> (in reverse alphabetical order). Part of the constructions have been documented in the literature on almost simple groups, or the results have been used in such publications, see for example the references in <a href="chapBib.html#biBCCN85">[CCNPW85]</a> and <a href="chapBib.html#biBBN95">[BN95]</a>.</p>
<p>If you use the <strong class="pkg">ATLAS</strong> of Group Representations to solve a problem then please send a short email to <span class="URL"><a href="mailto:R.A.Wilson@qmul.ac.uk">R.A.Wilson@qmul.ac.uk</a></span> about it. The <strong class="pkg">ATLAS</strong> of Group Representations database should be referenced with the entry <a href="chapBib.html#biBAGR">[ATLAS]</a> in the bibliography of this manual.</p>
<p>If your work made use of functions of the <strong class="pkg">GAP</strong> interface (see Section <a href="chap1.html#X8033B61682EE6A23"><b>1.2</b></a>) then you should also reference this interface, as follows.</p>
<table class="example">
<tr><td><pre>
@misc{ AtlasRep1.4,
author = {Wilson, R. A. and Parker, R. A. and Nickerson, S. and
Bray, J. N. and Breuer, T.},
title = {{AtlasRep}, A \textsf{GAP} Interface to the Atlas of
Group Representations,
{V}ersion 1.4},
month = {June},
year = {2008},
note = {Refereed \textsf{GAP} package},
howpublished = {http://www.math.rwth-aachen.de/\~{}Thomas.Breuer/atlasrep}
}
</pre></td></tr></table>
<p>For referencing the <strong class="pkg">GAP</strong> system in general, use the entry <a href="chapBib.html#biBGAP4410">[GAP]</a> in the bibliography of this manual, see also</p>
<p><span class="URL"><a href="http://www.gap-system.org">http://www.gap-system.org</a></span>.</p>
<p><a id="X8033B61682EE6A23" name="X8033B61682EE6A23"></a></p>
<h4>1.2 <span class="Heading">The GAP Interface to the <strong class="pkg">ATLAS</strong> of Group Representations</span></h4>
<p>The <strong class="pkg">GAP</strong> interface to the <strong class="pkg">ATLAS</strong> of Group Representations consists of essentially two parts.</p>
<p>First, there is the <em>user interface</em> which allows the user to get an overview of the contents of the database, and to access the data in <strong class="pkg">GAP</strong> format; this is described in Chapter <a href="chap2.html#X87EAF8E578D95793"><b>2</b></a>. Advanced users may add their own data to the database, this is described in Chapter <a href="chap3.html#X7DF711157F9EFA28"><b>3</b></a>.</p>
<p>Second, there is <em>administrational information</em>, which covers also the declaration of <strong class="pkg">GAP</strong> objects such as straight line decisions and black box programs. This is important mainly for users interested in the actual implementation (e. g., for modifying the package) or in using it together with the <code class="code">C</code>-<strong class="pkg">MeatAxe</strong> standalone (see <a href="chapBib.html#biBRin98">[Rin98]</a>); this is described in Chapter <a href="chap5.html#X7F77634D817156B3"><b>5</b></a>.</p>
<p>Information concerning the <code class="code">C</code>-<strong class="pkg">MeatAxe</strong>, including the manual <a href="chapBib.html#biBRin98">[Rin98]</a>, can be found at</p>
<p><span class="URL"><a href="http://www.math.rwth-aachen.de/LDFM/homes/MTX">http://www.math.rwth-aachen.de/LDFM/homes/MTX</a></span></p>
<p>The <strong class="pkg">GAP</strong> interface should be regarded as preliminary. Hopefully it will become more user-friendly when the <strong class="pkg">ATLAS</strong> of Group Representations will be integrated into a larger <strong class="pkg">GAP</strong> database of groups and their representations, character tables, and tables of marks.</p>
<p>The interface and this manual have been provided by Thomas Breuer, except for the interpreter for black box programs (see Section <a href="chap4.html#X7BE856BC785A9E8F"><b>4.2</b></a>), which is due to Simon Nickerson. Comments, bug reports, and hints for improving the interface can be sent to <span class="URL"><a href="mailto:sam@math.rwth-aachen.de">sam@math.rwth-aachen.de</a></span>.</p>
<p><a id="X7DE8D7A88254E1DD" name="X7DE8D7A88254E1DD"></a></p>
<h4>1.3 <span class="Heading">Web Services for the <strong class="pkg">AtlasRep</strong> Package</span></h4>
<p>The home page of the <strong class="pkg">AtlasRep</strong> package is</p>
<p><span class="URL"><a href="http://www.math.rwth-aachen.de/~Thomas.Breuer/atlasrep">http://www.math.rwth-aachen.de/~Thomas.Breuer/atlasrep</a></span></p>
<p>Besides package archives and introductory package information, it provides</p>
<ul>
<li><p>the current file with the <em>table of contents</em> (the file <code class="file">gap/atlasprm.g</code> of the package), cf. <code class="func">ReloadAtlasTableOfContents</code> (<a href="chap1.html#X7AC3EA317EDBDA0E"><b>1.6-1</b></a>),</p>
</li>
<li><p>a <em>starter archive</em> containing many small representations and programs,</p>
</li>
<li><p>the list of <em>changes of server files</em> in HTML format (cf. <code class="func">AtlasOfGroupRepresentationsTestTableOfContentsRemoteUpdates</code> (<a href="chap1.html#X7E04B1C57C38DCB2"><b>1.6-4</b></a>)), and</p>
</li>
<li><p>an <em>overview of the data</em> available via the <strong class="pkg">GAP</strong> interface to the <strong class="pkg">ATLAS</strong> of Group Representations, in HTML format; this is similar to the information shown by <code class="func">DisplayAtlasInfo</code> (<a href="chap2.html#X79DACFFA7E2D1A99"><b>2.5-1</b></a>); further information can be found on the home page of the <strong class="pkg">ATLAS</strong> (see the introduction to this chapter).</p>
</li>
</ul>
<p><a id="X7F25ECBA7B675901" name="X7F25ECBA7B675901"></a></p>
<h4>1.4 <span class="Heading">Installing the <strong class="pkg">AtlasRep</strong> Package</span></h4>
<p>To install the package, unpack the archive file in a directory in the <code class="file">pkg</code> directory of your local copy of <strong class="pkg">GAP</strong> 4. This might be the <code class="file">pkg</code> directory of the <strong class="pkg">GAP</strong> 4 root directory, see <a href="../../../doc/htm/ref/CHAP074.htm#SECT001"><b>Reference: Installing a GAP Package</b></a> for details. It is however also possible to keep an additional <code class="file">pkg</code> directory in your private directories, see Section <a href="../../../doc/htm/ref/CHAP009.htm#SECT002"><b>Reference: GAP Root Directory</b></a>. The latter possibility <em>must</em> be chosen if you do not have write access to the <strong class="pkg">GAP</strong> root directory.</p>
<p>Data files (in the subdirectories <code class="file">datagens</code> and <code class="file">dataword</code> of the package) that are available from an earlier version of the package are in principle kept; see <code class="func">AtlasOfGroupRepresentationsTestTableOfContentsRemoteUpdates</code> (<a href="chap1.html#X7E04B1C57C38DCB2"><b>1.6-4</b></a>) for necessary updates.</p>
<p>If it is likely that one will work offline, it makes sense to install the "starter archive" that can be downloaded from the package's homepage.</p>
<p>The package consists entirely of <strong class="pkg">GAP</strong> code, no external binaries need to be compiled for the package itself. However, if the <strong class="pkg">GAP</strong> package <strong class="pkg">IO</strong> <a href="chapBib.html#biBIO">[Neu07]</a> is used to access remote data files (see Section <a href="chap1.html#X7CB4D8F887BE5E84"><b>1.7-3</b></a>) then its external binary must be available.</p>
<p>After unpacking the package archive, it should be checked whether the subdirectories <code class="file">datagens</code> and <code class="file">dataword</code> of the package directory have write permissions for those users who will download files from the servers. The recommended permissions under UNIX are set as follows.</p>
<table class="example">
<tr><td><pre>
you@unix> chmod 1777 atlasrep/data*
you@unix> ls -ld atlasrep/data*
drwxrwxrwt 3 you you 1024 Oct 31 12:34 datagens
drwxrwxrwt 3 you you 1024 Oct 31 12:34 dataword
</pre></td></tr></table>
<p>For checking the installation of the package, you should start <strong class="pkg">GAP</strong>, load the package (see Section <a href="chap1.html#X8313A28A849E489B"><b>1.5</b></a>), and then call</p>
<table class="example">
<tr><td><pre>
gap> ReadPackage( "atlasrep", "tst/testinst.g" );
</pre></td></tr></table>
<p>If the installation is o.k. then the <strong class="pkg">GAP</strong> prompt appears without anything else being printed; otherwise the output lines tell you what should be changed.</p>
<p>More test files are available in the <code class="file">tst</code> directory of the package, see Section <a href="chap5.html#X84A565E482DBF4C1"><b>5.8</b></a> for details.</p>
<p><code class="file">PDF</code> and HTML versions of the package manual are available in the <code class="file">doc</code> directory of the package.</p>
<p><a id="X8313A28A849E489B" name="X8313A28A849E489B"></a></p>
<h4>1.5 <span class="Heading">Loading the <strong class="pkg">AtlasRep</strong> Package</span></h4>
<p>The <strong class="pkg">AtlasRep</strong> package may be loaded automatically when <strong class="pkg">GAP</strong> is started, for example when other <strong class="pkg">GAP</strong> packages require it, or it has to be loaded within the <strong class="pkg">GAP</strong> session as follows.</p>
<table class="example">
<tr><td><pre>
gap> LoadPackage( "atlasrep" );
true
</pre></td></tr></table>
<p>See <a href="../../../doc/htm/ref/CHAP074.htm#SECT002"><b>Reference: Loading a GAP Package</b></a> for details about these alternatives.</p>
<p><a id="X80D437A481096921" name="X80D437A481096921"></a></p>
<h4>1.6 <span class="Heading">Maintaining the Local Data of the <strong class="pkg">AtlasRep</strong>
Package</span></h4>
<p><a id="sect:maintain"/> The current <em>table of contents</em> of the database is contained in the file <code class="file">gap/atlasprm.g</code> of the <strong class="pkg">AtlasRep</strong> package. This file is read by default when the package is loaded. It may happen that new data files have been added to the servers since the last release of the <strong class="pkg">AtlasRep</strong> package, thus it is useful to update the table of contents of the package from time to time.</p>
<p>For that, one can fetch the most recent version of the file <code class="file">gap/atlasprm.g</code> from the home page of the package (see Section <a href="chap1.html#X7DE8D7A88254E1DD"><b>1.3</b></a>), either by calling <code class="func">ReloadAtlasTableOfContents</code> (<a href="chap1.html#X7AC3EA317EDBDA0E"><b>1.6-1</b></a>) in a <strong class="pkg">GAP</strong> session or "by hand". In the latter case, the new file can then be read into the <strong class="pkg">GAP</strong> session via <code class="func">ReplaceAtlasTableOfContents</code> (<a href="chap1.html#X847A5AFD7B5D8570"><b>1.6-3</b></a>). Alternatively, one can add a line to the user's <code class="file">.gaprc</code> file (see <a href="../../../doc/htm/ref/CHAP003.htm#SECT004"><b>Reference: The .gaprc file</b></a>), which assigns the filename of the current <code class="file">gap/atlasprm.g</code> file (as an absolute path or relative to the user's home directory, cf. <code class="func">Directory</code> (<a href="../../../doc/htm/ref/CHAP009.htm#SECT003"><b>Reference: Directory</b></a>)) to the global variable <code class="code">ATLASREP_TOCFILE</code>; in this case, this file is read instead of the one from the package distribution when the package is loaded.</p>
<p>Users who have write access to the directory where the <strong class="pkg">AtlasRep</strong> package is installed can alternatively use the <code class="file">maketoc</code> script in the <code class="file">etc</code> directory of the package for regularly updating the file <code class="file">gap/atlasprm.g</code>. Users without this write access can store the new file in a different place, and read it with <code class="func">ReplaceAtlasTableOfContents</code> (<a href="chap1.html#X847A5AFD7B5D8570"><b>1.6-3</b></a>).</p>
<p><a id="X7AC3EA317EDBDA0E" name="X7AC3EA317EDBDA0E"></a></p>
<h5>1.6-1 ReloadAtlasTableOfContents</h5>
<div class="func"><table class="func" width="100%"><tr><td class="tdleft"><code class="func">> ReloadAtlasTableOfContents</code>( <var class="Arg">dirname</var> )</td><td class="tdright">( function )</td></tr></table></div>
<p><b>Returns: </b><code class="keyw">fail</code> if the required table of contents could not be reloaded, otherwise <code class="keyw">true</code>.</p>
<p>Let <var class="Arg">dirname</var> be a string, which must be one of <code class="code">"remote"</code>, <code class="code">"local"</code>, or the name of a private data directory (see Chapter <a href="chap3.html#X7DF711157F9EFA28"><b>3</b></a>).</p>
<p>In the case of <code class="code">"remote"</code>, the file <code class="code">atlasprm.g</code> is fetched from the package's home page, and then read into <strong class="pkg">GAP</strong>. In the case of <code class="code">"local"</code>, the subset of the data listed in the <code class="code">"remote"</code> table of contents is considered that are actually available in the local data directories. In the case of a private directory, its contents is inspected, and the table of contents for <var class="Arg">dirname</var> is replaced by the one obtained from inspecting the actual contents of the data directories (see Section <a href="chap5.html#X7D66C94E7A0F2252"><b>5.7</b></a>).</p>
<p><a id="X7E3E52D380C20363" name="X7E3E52D380C20363"></a></p>
<h5>1.6-2 StoreAtlasTableOfContents</h5>
<div class="func"><table class="func" width="100%"><tr><td class="tdleft"><code class="func">> StoreAtlasTableOfContents</code>( <var class="Arg">filename</var> )</td><td class="tdright">( function )</td></tr></table></div>
<p>Let <var class="Arg">filename</var> be a string. This function prints the loaded table of contents of the servers to the file with name <var class="Arg">filename</var>.</p>
<p><a id="X847A5AFD7B5D8570" name="X847A5AFD7B5D8570"></a></p>
<h5>1.6-3 ReplaceAtlasTableOfContents</h5>
<div class="func"><table class="func" width="100%"><tr><td class="tdleft"><code class="func">> ReplaceAtlasTableOfContents</code>( <var class="Arg">filename</var> )</td><td class="tdright">( function )</td></tr></table></div>
<p>Let <var class="Arg">filename</var> be the name of a file that has been created with <code class="func">StoreAtlasTableOfContents</code> (<a href="chap1.html#X7E3E52D380C20363"><b>1.6-2</b></a>).</p>
<p><code class="func">ReplaceAtlasTableOfContents</code> first removes the information that <strong class="pkg">GAP</strong> has stored about the table of contents of the servers, and then reads the file with name <var class="Arg">filename</var>, thus replacing the previous information by the stored one.</p>
<p><a id="X7E04B1C57C38DCB2" name="X7E04B1C57C38DCB2"></a></p>
<h5>1.6-4 AtlasOfGroupRepresentationsTestTableOfContentsRemoteUpdates</h5>
<div class="func"><table class="func" width="100%"><tr><td class="tdleft"><code class="func">> AtlasOfGroupRepresentationsTestTableOfContentsRemoteUpdates</code>( <var class="Arg"></var> )</td><td class="tdright">( function )</td></tr></table></div>
<p><b>Returns: </b>the list of names of all locally available data files that should be removed.</p>
<p>This function fetches the file <code class="file">changes.html</code> from the package's home page, extracts the times of changes for the data files in question, and compares them with the times of the last changes of the local data files. For that, the <strong class="pkg">GAP</strong> package <strong class="pkg">IO</strong> <a href="chapBib.html#biBIO">[Neu07]</a> is needed; if it is not available then an error message is printed, and <code class="keyw">fail</code> is returned.</p>
<p>If the time of the last modification of a server file is later than that of the local copy then the local file must be updated. (This means that <code class="code">touch</code>ing files in the local directories will cheat this function.)</p>
<p>It is useful that a system administrator (i. e., someone who has the permission to remove files from the data directories) runs this function from time to time, and afterwards removes the files in the list that is returned. This way, new versions of these files will be fetched automatically from the servers when a user asks for their data.</p>
<p><a id="X7B04D2287CC44DE5" name="X7B04D2287CC44DE5"></a></p>
<h4>1.7 <span class="Heading">User Parameters for the <strong class="pkg">AtlasRep</strong> Package</span></h4>
<p>This section lists global parameters for which it might make sense to change their defaults by assignments to global variables, either just for the current <strong class="pkg">GAP</strong> session or as user preferences in the user's <code class="file">.gaprc</code> file (see <a href="../../../doc/htm/ref/CHAP003.htm#SECT004"><b>Reference: The .gaprc file</b></a>).</p>
<p><a id="X7E1934D2780D108F" name="X7E1934D2780D108F"></a></p>
<h5>1.7-1 <span class="Heading">Local or Remote Access</span></h5>
<p>There are two possibilities to use the <strong class="pkg">AtlasRep</strong> package.</p>
<dl>
<dt><strong class="Mark"><em>Local access only (offline)</em></strong></dt>
<dd><p>You can restrict he access to the data that are actually stored in the local installation of <strong class="pkg">GAP</strong>.</p>
</dd>
<dt><strong class="Mark"><em>Remote access (online)</em></strong></dt>
<dd><p>If your computer is connected to a network that provides access to the <strong class="pkg">ATLAS</strong> data (for example the internet) then the functions of the package may fetch the requested data automatically from remote servers when they are required for the first time; these data are then by default stored in the local copy, so later access to them needs no network transfer.</p>
</dd>
</dl>
<p>The latter possibility is presently not used by other <strong class="pkg">GAP</strong> packages, so it may be regarded as an important feature of the <strong class="pkg">AtlasRep</strong> package. Anyhow it requires a few words of explanation.</p>
<p>The possibility of online access reflects in particular the fact that the <strong class="pkg">ATLAS</strong> of Group Representations is designed as an <em>open database</em>, it is expected to grow. As soon as the developers of the <strong class="pkg">ATLAS</strong> of Group Representations add new information to the servers, these data become available in <strong class="pkg">GAP</strong> when remote access is enabled, after one has updated the corresponding table of contents (see Section <a href="chap1.html#X80D437A481096921"><b>1.6</b></a>).</p>
<p>Remote access is enabled if and only if the value of the <code class="code">remote</code> component of the global variable <code class="func">AtlasOfGroupRepresentationsInfo</code> (<a href="chap5.html#X7BEC94A6781E126E"><b>5.1-5</b></a>) is <code class="keyw">true</code>. If one wants to work offline, i.e., if one does <em>not</em> want <strong class="pkg">GAP</strong> to attempt accessing remote data then this value must be set to <code class="keyw">false</code>.</p>
<p>Conversely, if the default value of the <code class="code">remote</code> component in your <strong class="pkg">GAP</strong> installation is <code class="keyw">false</code> then changing this value to <code class="keyw">true</code> may be not successful. First, it might be the case that no server is reachable. And second, if one can in principle <em>download</em> files from a server then it might be impossible to actually <em>store</em> these files in the data directories of the installed package; in this case, it is advisable to install the whole package or just its data directories in a private directory, see <a href="../../../doc/htm/ref/CHAP009.htm#SECT002"><b>Reference: GAP Root Directory</b></a> for details.</p>
<p><a id="X826B8F128277032E" name="X826B8F128277032E"></a></p>
<h5>1.7-2 <span class="Heading">Adding and Removing Servers</span></h5>
<p>When access to remote data is enabled (see Section <a href="chap1.html#X7E1934D2780D108F"><b>1.7-1</b></a>) then the available servers are given by the <code class="code">servers</code> component of the global variable <code class="func">AtlasOfGroupRepresentationsInfo</code> (<a href="chap5.html#X7BEC94A6781E126E"><b>5.1-5</b></a>).</p>
<p><em>Removing</em> entries from this list means to disable access to the corresponding servers, <em>adding</em> entries makes the corresponding servers available. Of course the latter makes sense only if the new servers really exist, for example in a local network.</p>
<p>Currently there is just one remote server. As soon as other servers become available, or a server name is changed which makes it necessary to adjust the <code class="code">servers</code> component, this will be announced in the <strong class="pkg">GAP</strong> Forum, cf. <a href="../../../doc/htm/tut/CHAP001.htm#SECT005"><b>Tutorial: Further Information about GAP</b></a>. The same holds when upgrades of the package become available.</p>
<p><a id="X7CB4D8F887BE5E84" name="X7CB4D8F887BE5E84"></a></p>
<h5>1.7-3 <span class="Heading">Accessing Data Files with the <strong class="pkg">GAP</strong> Package <strong class="pkg">IO</strong>
or with <code class="file">wget</code></span></h5>
<p>When access to remote data is enabled (see Section <a href="chap1.html#X7E1934D2780D108F"><b>1.7-1</b></a>) then one needs either the <strong class="pkg">GAP</strong> package <strong class="pkg">IO</strong> <a href="chapBib.html#biBIO">[Neu07]</a> or the external program <code class="file">wget</code> for accessing data files.</p>
<p>The chosen alternative is given by the value of the <code class="code">wget</code> component of the global variable <code class="func">AtlasOfGroupRepresentationsInfo</code> (<a href="chap5.html#X7BEC94A6781E126E"><b>5.1-5</b></a>).</p>
<p>If this component has the value <code class="keyw">true</code> then only <code class="file">wget</code> is tried, if the value is <code class="keyw">false</code> then only the <strong class="pkg">IO</strong> package is used. If this component is not bound or bound to another value than <code class="keyw">true</code> or <code class="keyw">false</code> (this is also the default) then the <strong class="pkg">IO</strong> package is preferred to <code class="file">wget</code> if this package is available, and otherwise <code class="file">wget</code> is tried.</p>
<p>Note that the system program <code class="file">wget</code> may be not available, and that it may require some work to install it; hints for that can be found on the home page of the <strong class="pkg">AtlasRep</strong> package (see Section <a href="chap1.html#X7DE8D7A88254E1DD"><b>1.3</b></a>).</p>
<p><a id="X7E0AC1127B4363E7" name="X7E0AC1127B4363E7"></a></p>
<h5>1.7-4 <span class="Heading">Compressed or Uncompressed Data Files</span></h5>
<p>When used with UNIX, <strong class="pkg">GAP</strong> can read <code class="file">gzip</code>ped files, see <a href="../../../doc/htm/ref/CHAP003.htm#SECT011"><b>Reference: Saving and Loading a Workspace</b></a>. If the component <code class="code">compress</code> of <code class="func">AtlasOfGroupRepresentationsInfo</code> (<a href="chap5.html#X7BEC94A6781E126E"><b>5.1-5</b></a>) has the value <code class="keyw">true</code> then each <strong class="pkg">MeatAxe</strong> format file that is fetched from a remote server is afterwards compressed with <code class="file">gzip</code>. This saves a lot of space if many <strong class="pkg">MeatAxe</strong> format files are accessed. (Note that data files in other formats are very small.) For example, at the time of the release of version 1.4 there were about 8400 data files in <strong class="pkg">MeatAxe</strong> format, which needed about 1400 MB in uncompressed text format and about 275 MB in compressed text format. The default value for the component <code class="code">compress</code> is <code class="keyw">false</code>.</p>
<p><a id="X83EE129B7A7650F2" name="X83EE129B7A7650F2"></a></p>
<h5>1.7-5 <span class="Heading">Customizing <code class="code">DisplayAtlasInfo</code></span></h5>
<p>The way how <code class="func">DisplayAtlasInfo</code> (<a href="chap2.html#X79DACFFA7E2D1A99"><b>2.5-1</b></a>) shows the requested overview is controlled by the component <code class="code">displayFunction</code> of <code class="func">AtlasOfGroupRepresentationsInfo</code> (<a href="chap5.html#X7BEC94A6781E126E"><b>5.1-5</b></a>). The default value is <code class="func">Print</code> (<a href="../../../doc/htm/ref/CHAP006.htm#SECT003"><b>Reference: Print</b></a>), another useful value is <code class="func">Pager</code> (<a href="../../../doc/htm/ref/CHAP002.htm#SECT004"><b>Reference: Pager</b></a>).</p>
<p><a id="X7FA485E479F6C3A0" name="X7FA485E479F6C3A0"></a></p>
<h5>1.7-6 <span class="Heading">Customizing the Access to Data Files</span></h5>
<p>By default, local data files are stored in the subdirectories <code class="file">datagens</code> and <code class="file">dataword</code> of the package, and the files are exactly the text files provided on the servers. However, a more flexible approach may be useful.</p>
<p>First, one may want to use <em>different file formats</em>, for example the <strong class="pkg">MeatAxe</strong> binary files that are provided by the servers parallel to the <strong class="pkg">MeatAxe</strong> text files. Second, one may want to use <em>a different directory structure</em>, for example the same structure as used on the servers –this makes sense for example if a local mirror of a server is available, because then one can read the server files directly, without transferring/copying them to another directory.</p>
<p>As a consequence, one would like to customize the meaning of the following three access steps.</p>
<dl>
<dt><strong class="Mark">Are the required filed locally available?</strong></dt>
<dd><p>The required files may have a different name or a different path, and the data can be available in one file or can be distributed to several files.</p>
</dd>
<dt><strong class="Mark">How can a file be made locally available?</strong></dt>
<dd><p>A different server file may be fetched or some postprocessing may be required.</p>
</dd>
<dt><strong class="Mark">How is the data of a file accessed by <strong class="pkg">GAP</strong>?</strong></dt>
<dd><p>A different function may be needed to read the file.</p>
</dd>
</dl>
<p>Details how to achieve this can be found in Section <a href="chap5.html#X81C5B5E78215169D"><b>5.2</b></a>.</p>
<p><a id="X866E1476853E42C2" name="X866E1476853E42C2"></a></p>
<h5>1.7-7 <span class="Heading">Reading Large Matrices over Finite Fields</span></h5>
<p>Matrices over finite fields in <strong class="pkg">GAP</strong> can be represented in a compressed format that needs less space than the corresponding text file. Such a <strong class="pkg">MeatAxe</strong> format text file can be read by <code class="func">ScanMeatAxeFile</code> (<a href="chap5.html#X83D5103780E1238F"><b>5.3-1</b></a>) either line by line (which is the default) or as a whole; the latter is faster but needs more space than the former. For example, a 4370 by 4370 matrix over the field with two elements (as occurs for an irreducible representation of the Baby Monster) requires less than 3 MB space in <strong class="pkg">GAP</strong> but the corresponding <strong class="pkg">MeatAxe</strong> format text file is more than 19 MB large, which means that when one reads the file with the fast variant, <strong class="pkg">GAP</strong> will temporarily grow by more than this value. One can change the mode by setting the global variable <code class="func">CMeatAxe.FastRead</code> (<a href="chap5.html#X85B6010C85A06CB6"><b>5.1-4</b></a>) to <code class="keyw">true</code> or <code class="keyw">false</code>, respectively.</p>
<p>Note that this parameter is meaningful only when <code class="func">ScanMeatAxeFile</code> (<a href="chap5.html#X83D5103780E1238F"><b>5.3-1</b></a>) is used. It has no effect for example if <strong class="pkg">MeatAxe</strong> binary files are read, cf. <code class="func">FFMatOrPermCMtxBinary</code> (<a href="chap5.html#X872FA00C7F791FBB"><b>5.3-5</b></a>).</p>
<p><a id="X80126409815DE5B6" name="X80126409815DE5B6"></a></p>
<h5>1.7-8 AtlasOfGroupRepresentationsShowUserParameters</h5>
<div class="func"><table class="func" width="100%"><tr><td class="tdleft"><code class="func">> AtlasOfGroupRepresentationsShowUserParameters</code>( <var class="Arg"></var> )</td><td class="tdright">( function )</td></tr></table></div>
<p>This function prints an overview of the current values of the user parameters introduced in this section.</p>
<p><a id="X7FB64AD37D4620E6" name="X7FB64AD37D4620E6"></a></p>
<h4>1.8 <span class="Heading">Extending the <strong class="pkg">ATLAS</strong> Database</span></h4>
<p>Users who have computed new representations that might be interesting for inclusion into the <strong class="pkg">ATLAS</strong> of Group representations can send the data in question to <span class="URL"><a href="mailto:R.A.Wilson@qmul.ac.uk">R.A.Wilson@qmul.ac.uk</a></span>.</p>
<p>It is also possible to store "private" representations and programs in local directories, and to use them in the same way as the "official" data. See Chapter <a href="chap3.html#X7DF711157F9EFA28"><b>3</b></a> for details.</p>
<p><a id="X7B864EDC7CB211FD" name="X7B864EDC7CB211FD"></a></p>
<h4>1.9 <span class="Heading">What's New in <strong class="pkg">AtlasRep</strong>,
Compared to Older Versions?</span></h4>
<p><a id="sect:news"/></p>
<p><a id="X86FE8602805AFA05" name="X86FE8602805AFA05"></a></p>
<h5>1.9-1 <span class="Heading">What's New in Version 1.4?</span></h5>
<ul>
<li><p>In addition to the group orders that were added in version 1.3 (see Section <a href="chap1.html#X820A9F6E834B7972"><b>1.9-3</b></a>), also many orders of maximal subgroups are now available. These values occur in the records returned by <code class="func">AtlasProgram</code> (<a href="chap2.html#X801F2E657C8A79ED"><b>2.5-3</b></a>) (for the case of <code class="code">"maxes"</code> type programs) and of the three argument version of <code class="func">AtlasGenerators</code> (<a href="chap2.html#X7D1CCCF8852DFF39"><b>2.5-2</b></a>); now a <code class="code">size</code> component may be bound. In these cases, the groups returned by <code class="func">AtlasSubgroup</code> (<a href="chap2.html#X7A3E460C82B3D9A3"><b>2.5-7</b></a>) have the <code class="func">Size</code> (<a href="../../../doc/htm/ref/CHAP028.htm#SECT003"><b>Reference: Size</b></a>) attribute set.</p>
<p>For this feature, the function <code class="func">AGRGNAN</code> (<a href="chap5.html#X8229700C8744F09B"><b>5.7-1</b></a>) was generalized, the function <code class="func">AtlasOfGroupRepresentationsTestWords</code> (<a href="chap5.html#X85F8ED98805FB495"><b>5.8-6</b></a>) was improved for <code class="code">"maxes"</code> type programs, and the function <code class="func">AtlasOfGroupRepresentationsTestSubgroupOrders</code> (<a href="chap5.html#X7999A5367E21B2CD"><b>5.8-2</b></a>) for preparing the values was added; this function serves also as a consistency check.</p>
</li>
<li><p>The information about the number of maximal subgroups, if available, is now used in <code class="func">DisplayAtlasInfo</code> (<a href="chap2.html#X79DACFFA7E2D1A99"><b>2.5-1</b></a>).</p>
</li>
<li><p>In many cases, straight line programs for computing generators of maximal subgroups of a group G, say, can in fact be used to compute also generators of maximal subgroups of downward extensions of G; if not then it may suffice to extend the given straight line programs by additional generators, see <code class="func">AtlasOfGroupRepresentationsTestCompatibleMaxes</code> (<a href="chap5.html#X87C41F1978086FE8"><b>5.8-4</b></a>).</p>
<p>Currently this yields more than 200 more possibilities to compute maximal subgroups, this means a growth by about 25 percent. For example, all maximal subgroups of 12.M_22 and 2.Fi_22 can now be accessed via <code class="func">AtlasGenerators</code> (<a href="chap2.html#X7D1CCCF8852DFF39"><b>2.5-2</b></a>).</p>
<p>(Of course this extension means only that one can access the straight line programs in question automatically via the <strong class="pkg">GAP</strong> interface. In principle one could have used them already before, by explicitly applying a straight line program for a factor group to generators of a group, and perhaps adding some element in the kernel of the natural epimorphism.)</p>
<p>For this feature, information about the compatibility of standard generators of groups and their factor groups was added, see <code class="func">AtlasOfGroupRepresentationsTestStdCompatibility</code> (<a href="chap5.html#X80C116968254C114"><b>5.8-3</b></a>).</p>
</li>
<li><p>The bibliographies contained in the <strong class="pkg">ATLAS</strong> of Finite Groups <a href="chapBib.html#biBCCN85">[CCNPW85]</a> and in the <strong class="pkg">ATLAS</strong> of Brauer Characters <a href="chapBib.html#biBJLPW95">[JLPW95]</a> are now available, see Section <a href="chap4.html#X7DD6CE0E79AAD61B"><b>4.4</b></a>.</p>
</li>
<li><p>If the <strong class="pkg">GAP</strong> package <strong class="pkg">Browse</strong> (see <a href="chapBib.html#biBBrowse1.2">[BL08]</a>) is loaded then the new functions <code class="func">BrowseMinimalDegrees</code> (<a href="chap4.html#X7F31A7CB841FE63F"><b>4.3-6</b></a>) and <code class="func">BrowseBibliographySporadicSimple</code> (<a href="chap4.html#X84ED4FC182C28198"><b>4.4-1</b></a>) are available; these functions can be called also by choosing the corresponding menu entries of the <strong class="pkg">Browse</strong> application <code class="func">BrowseGapData</code> (<a href="../../../pkg/Browse/doc/chap6.html#X850C786C87A4877B"><b>Browse: BrowseGapData</b></a>).</p>
</li>
<li><p>The function <code class="func">AtlasGroup</code> (<a href="chap2.html#X80AABEE783363B70"><b>2.5-6</b></a>) now admits also the return value of <code class="func">OneAtlasGeneratingSetInfo</code> (<a href="chap2.html#X841478AB7CD06D44"><b>2.5-4</b></a>) as its argument.</p>
</li>
</ul>
<p><a id="X83125C0278DBCEFB" name="X83125C0278DBCEFB"></a></p>
<h5>1.9-2 <span class="Heading">What's New in Version 1.3.1?</span></h5>
<p>This version was mainly released in order to fix a few problems. Now one does not get warnings about unbound variables when the package is loaded and the <strong class="pkg">GAP</strong> package <strong class="pkg">IO</strong> <a href="chapBib.html#biBIO">[Neu07]</a> is not available, and pathological situations in <code class="func">FFMatOrPermCMtxBinary</code> (<a href="chap5.html#X872FA00C7F791FBB"><b>5.3-5</b></a>) (concerning extremely short corrupted data files and different byte orderings in binary files) are handled more carefully.</p>
<p>Besides this, the two functions <code class="func">AtlasGroup</code> (<a href="chap2.html#X80AABEE783363B70"><b>2.5-6</b></a>) and <code class="func">AtlasSubgroup</code> (<a href="chap2.html#X7A3E460C82B3D9A3"><b>2.5-7</b></a>) were introduced, and the extended function <code class="func">QuaternionAlgebra</code> (<a href="../../../doc/htm/ref/CHAP060.htm#SECT004"><b>Reference: QuaternionAlgebra</b></a>) of <strong class="pkg">GAP</strong> 4.4.10 can now be used for describing base rings in <code class="func">OneAtlasGeneratingSetInfo</code> (<a href="chap2.html#X841478AB7CD06D44"><b>2.5-4</b></a>) and <code class="func">AllAtlasGeneratingSetInfos</code> (<a href="chap2.html#X84C2D76482E60E42"><b>2.5-5</b></a>). (This is the reason why this version of the package requires at least version 4.4.10 of <strong class="pkg">GAP</strong>.)</p>
<p><a id="X820A9F6E834B7972" name="X820A9F6E834B7972"></a></p>
<h5>1.9-3 <span class="Heading">What's New in Version 1.3?</span></h5>
<ul>
<li><p>The database was extended, see Section <a href="chap1.html#X7E0AC1127B4363E7"><b>1.7-4</b></a> for the number and size of files.</p>
</li>
<li><p>New data types and corresponding <strong class="pkg">GAP</strong> objects have been introduced, for representing semi-presentations, presentations, and programs for finding standard generators. For details, see <code class="func">AtlasProgram</code> (<a href="chap2.html#X801F2E657C8A79ED"><b>2.5-3</b></a>), Chapter <a href="chap4.html#X823949B17B185DFA"><b>4</b></a>, and Section <a href="chap5.html#X7D16BE31788F0E8A"><b>5.6</b></a>.</p>
</li>
<li><p>The records returned by the functions <code class="func">AtlasGenerators</code> (<a href="chap2.html#X7D1CCCF8852DFF39"><b>2.5-2</b></a>), <code class="func">OneAtlasGeneratingSetInfo</code> (<a href="chap2.html#X841478AB7CD06D44"><b>2.5-4</b></a>), and <code class="func">AllAtlasGeneratingSetInfos</code> (<a href="chap2.html#X84C2D76482E60E42"><b>2.5-5</b></a>) now contain the name and (if known) the order of the group in question, and also components describing the degree in the case of permutation representations or the dimension and the base ring of the natural module in the case of matrix representations.</p>
</li>
<li><p>For many of the groups, information about the minimal degree of faithful permutation representations and the minimal dimensions of faithful matrix representations in various characteristics is available for <code class="func">DisplayAtlasInfo</code> (<a href="chap2.html#X79DACFFA7E2D1A99"><b>2.5-1</b></a>), <code class="func">OneAtlasGeneratingSetInfo</code> (<a href="chap2.html#X841478AB7CD06D44"><b>2.5-4</b></a>), and <code class="func">AllAtlasGeneratingSetInfos</code> (<a href="chap2.html#X84C2D76482E60E42"><b>2.5-5</b></a>), see also Section <a href="chap4.html#X87E1F08D80C9E069"><b>4.3</b></a>. For these functions, also properties such as <code class="func">IsPrimeInt</code> (<a href="../../../doc/htm/ref/CHAP014.htm#SECT003"><b>Reference: IsPrimeInt</b></a>) can be used to describe the intended restriction of the output.</p>
</li>
<li><p>One can now use <code class="func">Pager</code> (<a href="../../../doc/htm/ref/CHAP002.htm#SECT004"><b>Reference: Pager</b></a>) in <code class="func">DisplayAtlasInfo</code> (<a href="chap2.html#X79DACFFA7E2D1A99"><b>2.5-1</b></a>), see Section <a href="chap1.html#X83EE129B7A7650F2"><b>1.7-5</b></a>.</p>
<p>An interactive alternative to <code class="func">DisplayAtlasInfo</code> (<a href="chap2.html#X79DACFFA7E2D1A99"><b>2.5-1</b></a>) is provided by the function <code class="func">BrowseAtlasInfo</code> (<a href="../../../pkg/Browse/doc/chap6.html#X8411AF928194C5AB"><b>Browse: BrowseAtlasInfo</b></a>) from the new (recommended) <strong class="pkg">GAP</strong> package <strong class="pkg">Browse</strong> <a href="chapBib.html#biBBrowse1.2">[BL08]</a>.</p>
</li>
<li><p>The functions <code class="func">OneAtlasGeneratingSetInfo</code> (<a href="chap2.html#X841478AB7CD06D44"><b>2.5-4</b></a>) and <code class="func">AllAtlasGeneratingSetInfos</code> (<a href="chap2.html#X84C2D76482E60E42"><b>2.5-5</b></a>) now admit also a list of group names as the first argument.</p>
</li>
<li><p>The functions for actually accessing the data are more flexible now, see Section <a href="chap1.html#X7FA485E479F6C3A0"><b>1.7-6</b></a>.</p>
</li>
<li><p>For transferring remote data, the <strong class="pkg">GAP</strong> package <strong class="pkg">IO</strong> <a href="chapBib.html#biBIO">[Neu07]</a> can now be used (and is recommended) as an alternative to <code class="file">wget</code>, see Section <a href="chap1.html#X7CB4D8F887BE5E84"><b>1.7-3</b></a>.</p>
</li>
<li><p>The address of the data server has changed. Since the access to the server is no longer possible via <code class="file">ftp</code>, the mechanim used up to version 1.2, which was based on <code class="file">ftp</code>, had to be rewritten.</p>
<p>The main consequence of this change is that information about updates of the table of contents is now provided at the package's homepage. This means that on the one hand, now package users cannot <em>compute</em> the table of contents directly from the server data, but on the other hand the update information can be <em>downloaded</em> without the necessity to install <code class="file">perl</code>.</p>
<p>Another consequence is that the system program <code class="file">ls</code> is no longer needed, see Section <a href="chap1.html#X8129F9467ED8C5B2"><b>1.9-5</b></a>.</p>
</li>
<li><p>The package manual has been restructured, extended and improved. It is now based on the package <strong class="pkg">GAPDoc</strong> <a href="chapBib.html#biBGAPDoc">[LN08]</a>.</p>
</li>
</ul>
<p><a id="X839B2C7A7B592F20" name="X839B2C7A7B592F20"></a></p>
<h5>1.9-4 <span class="Heading">What's New in Version 1.2?</span></h5>
<p>Not much.</p>
<p>The release of Version 1.2 became necessary first of all in order to provide a package version that is compatible with <strong class="pkg">GAP</strong> 4.4, since some cross-references into the <strong class="pkg">GAP</strong> Reference Manual were broken due to changes of section names. Additionally, several web addresses concerning the package itself were changed and thus had to be adjusted.</p>
<p>This opportunity was used</p>
<ul>
<li><p>to upgrade the administrational part for loading the package to the mechanism that is recommended for <strong class="pkg">GAP</strong> 4.4,</p>
</li>
<li><p>to extend the test suite, which now covers more consistency checks using the <strong class="pkg">GAP</strong> Character Table Library <a href="chapBib.html#biBCTblLib1.1.3">[Bre04]</a>,</p>
</li>
<li><p>to make the function <code class="func">ScanMeatAxeFile</code> (<a href="chap5.html#X83D5103780E1238F"><b>5.3-1</b></a>) more robust, due to the fact that the <strong class="pkg">GAP</strong> function <code class="func">PermList</code> (<a href="../../../doc/htm/ref/CHAP040.htm#SECT004"><b>Reference: PermList</b></a>) now returns <code class="keyw">fail</code> instead of raising an error,</p>
</li>
<li><p>to change the way how representations with prescribed properties are accessed (the new function <code class="func">OneAtlasGeneratingSetInfo</code> (<a href="chap2.html#X841478AB7CD06D44"><b>2.5-4</b></a>) is now preferred to the former <code class="code">OneAtlasGeneratingSet</code>, and <code class="func">AllAtlasGeneratingSetInfos</code> (<a href="chap2.html#X84C2D76482E60E42"><b>2.5-5</b></a>) has been added in order to provide programmatic access in parallel to the human readable descriptions printed by <code class="func">DisplayAtlasInfo</code> (<a href="chap2.html#X79DACFFA7E2D1A99"><b>2.5-1</b></a>)),</p>
</li>
<li><p>and last but not least to include the current table of contents of the underlying database.</p>
</li>
</ul>
<p>For <strong class="pkg">AtlasRep</strong> users, the new feature of <strong class="pkg">GAP</strong> 4.4 is particularly interesting that due to better kernel support, reading large matrices over finite fields is now faster than it was in <strong class="pkg">GAP</strong> 4.3.</p>
<p><a id="X8129F9467ED8C5B2" name="X8129F9467ED8C5B2"></a></p>
<h5>1.9-5 <span class="Heading">What's New in Version 1.1?</span></h5>
<p>The biggest change w.r.t. Version 1.1 is the addition of private extensions (see Chapter <a href="chap3.html#X7DF711157F9EFA28"><b>3</b></a>). It includes a new "free format" for straight line programs (see Section <a href="chap3.html#X7E186BFA7E59BD47"><b>3.2</b></a>). Unfortunately, this feature requires the system program <code class="file">ls</code>, so it may be not available for example under MS Windows operating systems. [But see Section <a href="chap1.html#X820A9F6E834B7972"><b>1.9-3</b></a>.]</p>
<p>In order to admit the addition of other types of data, the implementation of several functions has been changed. Data types are described in Section <a href="chap5.html#X86366BF08533DA5E"><b>5.5</b></a>. An example of a new data type are quaternionic representations (see Section <a href="chap5.html#X7D16BE31788F0E8A"><b>5.6</b></a>). The user interface itself (see Chapter <a href="chap2.html#X87EAF8E578D95793"><b>2</b></a>) remained the same.</p>
<p>As an alternative to <code class="code">perl</code>, one can use <code class="code">wget</code> now for transferring data files (see <a href="chap1.html#X7B04D2287CC44DE5"><b>1.7</b></a>).</p>
<p>Data files can be read much more efficiently in <strong class="pkg">GAP</strong> 4.3 than in <strong class="pkg">GAP</strong> 4.2. In Version 1.1 of the <strong class="pkg">AtlasRep</strong> package, this feature is used for reading matrices and permutations in <strong class="pkg">MeatAxe</strong> text format with <code class="func">ScanMeatAxeFile</code> (<a href="chap5.html#X83D5103780E1238F"><b>5.3-1</b></a>). As a consequence, (at least) <strong class="pkg">GAP</strong> 4.3 is required for <strong class="pkg">AtlasRep</strong> Version 1.1.</p>
<p>The new <code class="code">compress</code> component of the global variable <code class="func">AtlasOfGroupRepresentationsInfo</code> (<a href="chap5.html#X7BEC94A6781E126E"><b>5.1-5</b></a>) allows one to store data files automatically in <code class="file">gzip</code>ped form.</p>
<p>For matrix representations in characteristic zero, invariant forms and generators for the centralizer algebra are now accessible in <strong class="pkg">GAP</strong> if they are contained in the source files --this information had been ignored in Version 1.0 (see <code class="func">AtlasOfGroupRepresentationsTestTableOfContentsRemoteUpdates</code> (<a href="chap1.html#X7E04B1C57C38DCB2"><b>1.6-4</b></a>) for necessary updates).</p>
<p>Additional information is now available via the internet (see <a href="chap1.html#X7DE8D7A88254E1DD"><b>1.3</b></a>).</p>
<p>The update facilities have been extended (see <a href="chap1.html#X80D437A481096921"><b>1.6</b></a>).</p>
<p>The manual is now distributed also in pdf and HTML format; on the other hand, the PostScript format manual is no longer contained in the archives.</p>
<p>Apart from these changes, a few minor bugs in the handling of <strong class="pkg">MeatAxe</strong> files have been fixed, typos in the documentation have been corrected, and the syntax checks for <strong class="pkg">ATLAS</strong> straight line programs (see <a href="chap5.html#X7FEE162B7F63BEA0"><b>5.4</b></a>) have been improved.</p>
<p><a id="X8207E35380A4BAFC" name="X8207E35380A4BAFC"></a></p>
<h4>1.10 <span class="Heading">Acknowledgments</span></h4>
<p>The perl script that had been used for fetching remote data until version 1.2 had been kindly provided by Frank Lübeck and Max Neunhöffer. Thanks also to Greg Gamble and Alexander Hulpke for technical hints concerning "standard" perl.</p>
<p>Ulrich Kaiser helped with preparing the package for MS Windows.</p>
<p>The idea to support private extensions of the package (see Chapter <a href="chap3.html#X7DF711157F9EFA28"><b>3</b></a>) is due to Klaus Lux. He used a preliminary version of <strong class="pkg">AtlasRep</strong> Version 1.1, and helped to fix several bugs.</p>
<p>The functions <code class="func">CMtxBinaryFFMatOrPerm</code> (<a href="chap5.html#X8477AA668733255C"><b>5.3-4</b></a>) and <code class="func">FFMatOrPermCMtxBinary</code> (<a href="chap5.html#X872FA00C7F791FBB"><b>5.3-5</b></a>) were contributed by Frank Lübeck.</p>
<p>The <strong class="pkg">GAPDoc</strong> package <a href="chapBib.html#biBGAPDoc">[LN08]</a>, which is used for processing the package manual, was written by Frank Lübeck and Max Neunhöffer.</p>
<p>The <strong class="pkg">GAP</strong> package <strong class="pkg">IO</strong> <a href="chapBib.html#biBIO">[Neu07]</a>, which is recommended for transferring data, was written by Max Neunhöffer.</p>
<p>Max has also suggested the generalization of the data access described in Section <a href="chap1.html#X7FA485E479F6C3A0"><b>1.7-6</b></a>.</p>
<p>Gunter Malle had suggested to make the information about representations of minimal degree accessible.</p>
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