<h4>1.1 <span class="Heading">Introduction to the <strong class="pkg">GUAVA</strong> package</span></h4>
<p>This is the manual of the GAP package <strong class="pkg">GUAVA</strong>. <strong class="pkg">GUAVA</strong> contains many functions that allow one to perform computations relevant to the theory of error-correcting codes. This version of <strong class="pkg">GUAVA</strong> requires GAP 4.4.5 or later. The current version of <strong class="pkg">GUAVA</strong> (3.20) was updated to work with GAP 4.14.0.</p>
<p>The functions in <strong class="pkg">GUAVA</strong> can be divided into three subcategories:</p>
<ul>
<li><p>Construction of codes: <strong class="pkg">GUAVA</strong> can construct unrestricted, linear and cyclic codes. Information about the code, such as operations applicable to the code, is stored in a record-like data structure called a GAP object.</p>
</li>
<li><p>Manipulations of codes: Manipulations transform one code into another, or construct a new code from two codes. The new code can profit from the data in the record of the old code(s), so in these cases calculation time often decreases.</p>
</li>
<li><p>Computations of information about codes: <strong class="pkg">GUAVA</strong> can calculate important parameters of codes quickly. The results are stored in the codes' object components.</p>
</li>
</ul>
<p>Except for the automorphism group and isomorphism testing functions, which make use of J.S. Leon's programs (see <a href="chapBib_mj.html#biBLeon91">[Leo91]</a> and the documentation in the 'src/leon' subdirectory of the 'guava' directory for some details), and <code class="func">MinimumWeight</code> (<a href="chap4_mj.html#X84EDF67B86B4154C"><span class="RefLink">4.8-5</span></a>) function, <strong class="pkg">GUAVA</strong> is written in the GAP language, and runs on any system supporting GAP4.4 and above. Several algorithms that need the speed were integrated in the GAP kernel.</p>
<p>Good general references for error-correcting codes and the technical terms in this manual are MacWilliams and Sloane <a href="chapBib_mj.html#biBMS83">[MS83]</a> and also Huffman and Pless <a href="chapBib_mj.html#biBHP03">[HP03]</a>.</p>
<p>The most recent version of GAP (4.8) comes complete with all of the packages -- including <strong class="pkg">GUAVA</strong>. Thus the following instructions are not usually applicable but may be needed in certain circumstances.</p>
<p>To install <strong class="pkg">GUAVA</strong> unpack the archive file in a directory in the `pkg' hierarchy of your version of GAP 4.</p>
<p>After unpacking <strong class="pkg">GUAVA</strong> the GAP-only part of <strong class="pkg">GUAVA</strong> is installed. The parts of <strong class="pkg">GUAVA</strong> depending on J. Leon's backtrack programs package (for computing automorphism groups) are only available in a UNIX-like environment, where you should proceed as follows: Go to the newly created `guava' directory and call <code class="code">`./configure /gappath'</code> where <code class="code">/gappath</code> is the path to the GAP home directory. So for example, if you install the package in the main `pkg'directory call</p>
<pre class="normal">
./configure ../..
</pre>
<p>This will fetch the architecture type for which GAP has been compiled last and create a `Makefile'. Now call</p>
<pre class="normal">
make
</pre>
<p>to compile the binaries and install them in the appropriate place. For a Windows machine with CYGWIN installed - see <span class="URL"><a href="https://www.cygwin.com/">https://www.cygwin.com/</a></span> - instructions for compiling Leon's binaries are likely to be similar to those above.</p>
<p>If it is not already installed, you should also install the GAP package <strong class="pkg">SONATA</strong>. You can download this from the GAP website and unpack it in the `pkg' subdirectory.</p>
<p>This completes the installation of <strong class="pkg">GUAVA</strong> for a single architecture. If you use this installation of <strong class="pkg">GUAVA</strong> on different hardware platforms you will have to compile the binaries for each platform separately.</p>
<p>After starting up GAP, the <strong class="pkg">GUAVA</strong> package needs to be loaded. Load <strong class="pkg">GUAVA</strong> by typing at the GAP prompt:</p>
<p>If <strong class="pkg">GUAVA</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">GUAVA</strong>, you might consider adding <strong class="pkg">GUAVA</strong> to the "PackagesToLoad" preference in your gap initialization file. (Usually <code class="file">gap.ini</code> which should be located in your home directory.) Type <code class="file">GAPInfo.UserGapRoot;</code> at the GAP prompt to find the location of your initialization file. If none exists, the command <code class="file">WriteGapIniFile();</code> will create a default <code class="file">gap.ini</code> file which you can then modify.</p>
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