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<div class="ChapSects"><a href="chap1.html#X7DFB63A97E67C0A1">1 <span class="Heading">Introduction</span></a>
<div class="ContSect"><span class="nocss"> </span><a href="chap1.html#X7EC1C3E779AE8717">1.1 <span class="Heading">Introduction to the <strong class="pkg">HAPprime</strong> package</span></a>
</div>
<div class="ContSect"><span class="nocss"> </span><a href="chap1.html#X7D20BAAF862B41E9">1.2 <span class="Heading">Required software</span></a>
</div>
<div class="ContSect"><span class="nocss"> </span><a href="chap1.html#X7CFA390D7DE91268">1.3 <span class="Heading">Installing <strong class="pkg">HAPprime</strong></span></a>
</div>
<div class="ContSect"><span class="nocss"> </span><a href="chap1.html#X84983C5A84213019">1.4 <span class="Heading">Loading and testing <strong class="pkg">HAPprime</strong></span></a>
</div>
<div class="ContSect"><span class="nocss"> </span><a href="chap1.html#X7F4F8D6F7CD6B765">1.5 <span class="Heading">Documentation</span></a>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X80F4100D783E407A">1.5-1 MakeHAPprimeDoc</a></span>
</div>
<div class="ContSect"><span class="nocss"> </span><a href="chap1.html#X845E795E8537ABBA">1.6 <span class="Heading">Displaying progress and calculation information</span></a>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X80E9D70E843A8C2C">1.6-1 InfoHAPprime</a></span>
</div>
</div>
<h3>1 <span class="Heading">Introduction</span></h3>
<p><a id="X7EC1C3E779AE8717" name="X7EC1C3E779AE8717"></a></p>
<h4>1.1 <span class="Heading">Introduction to the <strong class="pkg">HAPprime</strong> package</span></h4>
<p><strong class="pkg">HAPprime</strong> is a package for the <strong class="pkg">GAP</strong> computer algebra system (<span class="URL"><a href="http://www.gap-system.org/">http://www.gap-system.org/</a></span>), and which extends the <strong class="pkg">HAP</strong> `Homological Algebra Progamming' package written by Graham Ellis (<span class="URL"><a href="http://hamilton.nuigalway.ie/Hap/www/">http://hamilton.nuigalway.ie/Hap/www/</a></span>). It provides algorithms and data structures for calculating cohomology ring presentations and resolutions of small prime-power groups. As well as new functions, <strong class="pkg">HAPprime</strong> also provides some equivalents for some existing <strong class="pkg">HAP</strong> functions that are much more memory-efficient and occasionally faster.</p>
<p>In particular, the main reasons you may want to use <strong class="pkg">HAPprime</strong> are</p>
<ul>
<li><p>the calculation of resolutions of prime-power groups in <strong class="pkg">HAPprime</strong> uses significantly less memory than the equivalent function in <strong class="pkg">HAP</strong>, allowing resolutions (and cohomology ring presentations) of larger groups to be calculated (see Section <a href="chap2.html#X87AD96A584D60140"><b>2.3</b></a>);</p>
</li>
<li><p><strong class="pkg">HAPprime</strong> can compute polynomial ring presentations for cohomology rings calculated using either <strong class="pkg">HAP</strong> or <strong class="pkg">HAPprime</strong> (see Section <a href="chap2.html#X81BCBAA18423E1C8"><b>2.2-1</b></a>);</p>
</li>
<li><p>we provide a method which ensures that complete and correct cohomology rings are computed. This is a an implementation of Len Evens' original proof of the finite presentation of the cohomology rings (see Section <a href="chap2.html#X825971A27C00C1B6"><b>2.2-2</b></a>).</p>
</li>
</ul>
<p><a id="X7D20BAAF862B41E9" name="X7D20BAAF862B41E9"></a></p>
<h4>1.2 <span class="Heading">Required software</span></h4>
<p>The <strong class="pkg">HAPprime</strong> package requires <strong class="pkg">GAP</strong> version 4.4 or greater and <strong class="pkg">HAP</strong> version 1.8.9 or greater. For calculating provably-correct cohomology rings, the <strong class="pkg">Singular</strong> commutative algebra system (<span class="URL"><a href="http://www.singular.uni-kl.de/">http://www.singular.uni-kl.de/</a></span>) and the <strong class="pkg">singular</strong> <strong class="pkg">GAP</strong> package are also required.</p>
<p><a id="X7CFA390D7DE91268" name="X7CFA390D7DE91268"></a></p>
<h4>1.3 <span class="Heading">Installing <strong class="pkg">HAPprime</strong></span></h4>
<p>To install the <strong class="pkg">HAPprime</strong> Package, unpack the archive file into your <strong class="pkg">GAP</strong> packages directory (either usually the <code class="file">pkg</code> directory of your <strong class="pkg">GAP</strong> 4 installation if you have access to it, or some local <code class="file">pkg</code> directory that <strong class="pkg">GAP</strong> can find). The <strong class="pkg">HAPprime</strong> files will all be installed in a subdirectory called <code class="file">happrime-0.3.2</code>.</p>
<p><a id="X84983C5A84213019" name="X84983C5A84213019"></a></p>
<h4>1.4 <span class="Heading">Loading and testing <strong class="pkg">HAPprime</strong></span></h4>
<p>The <strong class="pkg">HAPprime</strong> package is not loaded by default when <strong class="pkg">GAP</strong> is started. To load the package, type the following at the <strong class="pkg">GAP</strong> prompt:</p>
<table class="example">
<tr><td><pre>
gap> LoadPackage( "HAPprime");
</pre></td></tr></table>
<p>If <strong class="pkg">HAPprime</strong> isn't already in memory, it is loaded and the author information is displayed. If you are a frequent user of <strong class="pkg">HAPprime</strong>, you might consider putting this line in your <code class="file">.gaprc</code> file.</p>
<p>The correct installation of <strong class="pkg">HAPprime</strong> can be tested by using the test routine <code class="file">tst/testall.g</code>:</p>
<table class="example">
<tr><td><pre>
gap> ReadPackage("HAPprime", "tst/testall.g");
+ HAPprime version 0.3.2 general tests
+ GAP4stones: 371057
+ HAPprime version 0.3.2 userguide examples
+ GAP4stones: 387662
+ HAPprime version 0.3.2 datatypes reference manual examples
+ GAP4stones: 382653
true
</pre></td></tr></table>
<p>The number of <code class="code">GAP4stones</code> will vary depending on your machine, but any additional lines of messages indicate problems with your installation.</p>
<p>The test routine calls a set of test files <a href="../../../../../gap4r4/doc/htm/ref/CHAP007.htm#SECT009"><b>Reference: Test Files</b></a> which can be found in the <code class="file">tst</code> directory of the <strong class="pkg">HAPprime</strong> installation. All of the routines listed in this user guide are tested, as are many of those in the datatype reference manual.</p>
<p><a id="X7F4F8D6F7CD6B765" name="X7F4F8D6F7CD6B765"></a></p>
<h4>1.5 <span class="Heading">Documentation</span></h4>
<p>The documentation for <strong class="pkg">HAPprime</strong> is in two parts. This document is the user guide, which covers the main functions provided by <strong class="pkg">HAPprime</strong> and examples of their use. There is also a more technical <strong class="pkg">HAPprime</strong> datatypes reference manual which gives details of the new <strong class="pkg">GAP</strong> datatypes defined and used internally by <strong class="pkg">HAPprime</strong>, as well as outlining the algorithms used by the package.</p>
<p><a id="X80F4100D783E407A" name="X80F4100D783E407A"></a></p>
<h5>1.5-1 MakeHAPprimeDoc</h5>
<div class="func"><table class="func" width="100%"><tr><td class="tdleft"><code class="func">> MakeHAPprimeDoc</code>( <var class="Arg">[manual-name]</var> )</td><td class="tdright">( function )</td></tr></table></div>
<p><b>Returns: </b>nothing</p>
<p>The two manuals supplied with <strong class="pkg">HAPprime</strong> - this user guide and the datatypes reference manual - are written using the <strong class="pkg">GAPDoc</strong> package and are available in PDF, HTML and text format. It should not be necessary to rebuild these files, but should you wish to do so then this can be done using the function <code class="func">MakeHAPprimeDoc</code>.</p>
<p>The optional argument <var class="Arg">manual-name</var> is a string specifying which manuals to build. It may be one of the following</p>
<ul>
<li><p><code class="code">"all"</code> builds both manuals. This is the default</p>
</li>
<li><p><code class="code">"userguide"</code> builds just the user guide</p>
</li>
<li><p><code class="code">"datatypes"</code> builds just the datatypes reference manual</p>
</li>
<li><p><code class="code">"internal"</code> builds both manuals, including the otherwise undocumented internal functions</p>
</li>
<li><p><code class="code">"testexamples"</code> builds neither manual, but tests all of the examples using <code class="func">TestManualExamples</code> (<a href="../../../../../gap4r4/pkg/GAPDoc-1.1/doc/chap5.html#X7F2555E07C499554"><b>GAPDoc: TestManualExamples</b></a>)</p>
</li>
</ul>
<p>As well as building the manuals, this function at the same time builds <strong class="pkg">GAP</strong> test files <a href="../../../../../gap4r4/doc/htm/ref/CHAP007.htm#SECT009"><b>Reference: Test Files</b></a> which means that all of the testable examples in the manuals are added to the <strong class="pkg">HAPprime</strong> test routines described in Section <a href="chap1.html#X84983C5A84213019"><b>1.4</b></a>.</p>
<p><a id="X845E795E8537ABBA" name="X845E795E8537ABBA"></a></p>
<h4>1.6 <span class="Heading">Displaying progress and calculation information</span></h4>
<p>By default, the functions in <strong class="pkg">HAPprime</strong> display no output (except for returning the result). The <code class="code">InfoHAPprime</code> info class can be used to enable the printing of progress and calculation information during processing. Since some computations with <strong class="pkg">HAPprime</strong> can take several hours, setting this to a higher level can be particularly useful for monitoring the progress of computations.</p>
<p><a id="X80E9D70E843A8C2C" name="X80E9D70E843A8C2C"></a></p>
<h5>1.6-1 InfoHAPprime</h5>
<div class="func"><table class="func" width="100%"><tr><td class="tdleft"><code class="func">> InfoHAPprime</code></td><td class="tdright">( info class )</td></tr></table></div>
<p>The <code class="code">InfoHAPprime</code> info class is used throughout the <strong class="pkg">HAPprime</strong> package. Use <code class="code">SetInfoLevel(InfoHAPprime, </code><var class="Arg">level</var><code class="code">)</code> to change the amount of information displayed about the progress of the computation (see <code class="func">SetInfoLevel</code> (<a href="../../../../../gap4r4/doc/htm/ref/CHAP007.htm#SECT004"><b>Reference: SetInfoLevel</b></a>) in the <strong class="pkg">GAP</strong> reference manual). The different distinct levels are:</p>
<ul>
<li><p><code class="code">0</code> print nothing (this is the default)</p>
</li>
<li><p><code class="code">1</code> print some information, mainly progress information during computations that may take some time</p>
</li>
<li><p><code class="code">2</code> print more detailed information, incluing details of internal calculations</p>
</li>
</ul>
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