<!-- %W atlasrep.xml GAP 4 package AtlasRep Thomas Breuer -->
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<Chapter Label="chap:atlasrep">
<Heading>Customizations of the &AtlasRep; Package</Heading>
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<Section Label="sect:Installing the AtlasRep Package">
<Heading>Installing the &AtlasRep; Package</Heading>
To install the package, unpack the archive file in a
directory in the <F>pkg</F> directory of your local copy of &GAP; 4.
This might be the <F>pkg</F> directory of the &GAP; 4 root directory,
see <Ref Sect="Installing a GAP Package" BookName="ref"/>
for details.
It is however also possible to keep an additional <F>pkg</F> directory
somewhere else,
see Section <Ref Sect="GAP Root Directories" BookName="ref"/>.
The latter possibility <E>must</E> be chosen if you do not have write access
to the &GAP; root directory.
<P/>
If it is likely that you will work offline, it makes sense to install the
<Q>starter archive</Q> that can be downloaded from the package's homepage.
<P/>
The package consists entirely of &GAP; code,
no external binaries need to be compiled for the package itself.
<P/>
After unpacking the package archive,
the write permissions for those directories should be checked
into which users will download files.
Every user can customize these paths via a user preference,
see Section <Ref Subsect="subsect:AtlasRepDataDirectory"/>,
the defaults are the subdirectories
<F>data*</F> of the package directory.
The recommended permissions under UNIX for the default directories
are set as follows.
<P/>
<Log><![CDATA[
you@unix> chmod 1777 atlasrep/data*
you@unix> ls -ld atlasrep/data*
drwxrwxrwt 3 you you 1024 Apr 12 12:34 dataext
drwxrwxrwt 3 you you 1024 Apr 12 12:34 datagens
drwxrwxrwt 3 you you 1024 Apr 12 12:34 datapkg
drwxrwxrwt 3 you you 1024 Apr 12 12:34 dataword
]]></Log>
<P/>
<#Include Label="[1]{testinst.g}">
<P/>
PDF, HTML, and text versions of the package manual are available
in the <F>doc</F> directory of the package.
</Section>
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<Section Label="sect:atlasrep user preferences">
<Heading>User Preferences of the &AtlasRep; Package</Heading>
This section describes global parameters for which it might make sense
to change their defaults, using &GAP;'s user preferences
(see <Ref Subsect="Configuring User preferences" BookName="ref"/>).
<P/>
<List>
<Item>
Is access to remote data allowed
(see Section <Ref Subsect="subsect:AtlasRepAccessRemoteFiles"/>)?
If yes then also the following parameters are of interest.
<P/>
<List>
<Item>
From where can the data be fetched
(see Section <Ref Subsect="subsect:AtlasRepTOCData"/>)?
</Item>
<Item>
Where are local copies of these data stored
(see Section <Ref Subsect="subsect:AtlasRepDataDirectory"/>)?
</Item>
<Item>
Shall files be compressed after they have been downloaded
(see Section <Ref Subsect="subsect:CompressDownloadedMeatAxeFiles"/>)?
</Item>
</List>
</Item>
<Item>
The following parameters influence reading and writing of local files.
<P/>
<List>
<Item>
What shall actually happen when data are requested by the interface
functions (see Section <Ref Subsect="subsect:FileAccessFunctions"/>)?
</Item>
<Item>
If the value of the user preference <C>FileAccessFunctions</C>
contains <C>"direct access to a local server"</C>,
what is its path
(see Section <Ref Subsect="subsect:AtlasRepLocalServerPath"/>)?
</Item>
<Item>
Shall <Ref Func="ScanMeatAxeFile"/> focus on small runtime or on small
space when reading &MeatAxe; text files
(see Section <Ref Subsect="subsect:HowToReadMeatAxeTextFiles"/>)?
</Item>
<Item>
Which kind of headers shall <Ref Func="MeatAxeString"/> create
(see Section <Ref Subsect="subsect:WriteHeaderFormatOfMeatAxeFiles"/>)?
</Item>
<Item>
Shall <Ref Func="MeatAxeString"/> interpret permutation matrices more as
permutations (mode 2) or as matrices (mode 1 or 6)
(see Section <Ref Subsect="subsect:WriteMeatAxeFilesOfMode2"/>)?
</Item>
<Item>
Shall the default for <Ref Func="CMtxBinaryFFMatOrPerm"/> be to write
binary files of zero-based or one-based permutations
(see Section <Ref Subsect="subsect:BaseOfMeatAxePermutation"/>)?
</Item>
</List>
</Item>
<Item>
Which function is used by <Ref Func="DisplayAtlasInfo"/> for printing to
the screen
(see Section <Ref Subsect="subsect:DisplayFunction"/>)?
</Item>
<Item>
How does <Ref Func="DisplayAtlasInfo"/> mark data that do not belong
to the core database
(see Section <Ref Subsect="subsect:AtlasRepMarkNonCoreData"/>)?
</Item>
<Item>
Shall debug messages be printed when local data files are read
(see Section <Ref Subsect="subsect:DebugFileLoading"/>)?
</Item>
</List>
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<Section Label="sect:Web Contents for the AtlasRep Package">
<Heading>Web Contents for the &AtlasRep; Package</Heading>
The <URL><Link>&ATLASREPHOME;</Link><LinkText>home page of the &AtlasRep; package</LinkText></URL>
provides
<P/>
<List>
<Item>
package archives,
</Item>
<Item>
introductory package information,
</Item>
<Item>
the current <E>table of contents</E> of core data in the file
<URL><LinkText><F>atlasprm.json</F></LinkText><Link>&ATLASREPHOME;/atlasprm.json</Link></URL>
of the package,
cf. <Ref Func="StringOfAtlasTableOfContents"/>,
</Item>
<Item>
the <URL><LinkText>list of changes of remote core data files</LinkText><Link>&ATLASREPHOME;/htm/data/changes.htm</Link></URL>,
</Item>
<Item>
a <URL><LinkText>starter archive</LinkText><Link>&ATLASREPHOME;/atlasrepdata.tar.gz</Link></URL>
containing many small representations and programs,
and
</Item>
<Item>
an <URL><LinkText>overview of the core data</LinkText><Link>&ATLASREPHOME;/htm/data</Link></URL>
in a similar format as the information shown by the function
<Ref Func="DisplayAtlasInfo"/> of the package;
more details can be found on the
<URL><LinkText>home page of the &ATLAS; of Group Representations</LinkText><Link>&ATLASSERVER;</Link></URL>.
</Item>
</List>
</Section>
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<Section Label="sect:Extending the Atlas Database">
<Heading>Extending the &ATLAS; Database</Heading>
Users who have computed new representations that might be interesting for
inclusion into the &ATLAS; of Group representations can send the data in
question to &WILSONMAIL;.
<P/>
It is also possible to make additional representations and programs
accessible for the &GAP; interface,
and to use these <Q>private</Q> data in the same way as the core data.
See Chapter <Ref Chap="chap:Private Extensions"/> for details.
Die Informationen auf dieser Webseite wurden
nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit,
noch Qualität der bereit gestellten Informationen zugesichert.
Bemerkung:
Die farbliche Syntaxdarstellung ist noch experimentell.
