This package provides an interface between GAP and PARI/GP. PARI/GP itself is not part of this package. It has to be obtained and installed independently of this package. Alnuth works with PARI/GP Version 2.5 or higher.
The package Alnuth is part of the standard distribution of GAP so that in most cases there is no need to install it separately. To use Alnuth you need to have PARI/GP installed. See the following section for information on PARI/GP.
In case you want to update Alnuth independently of your main GAP installation or if you are interested in an old version of Alnuth interfacing to KANT/KASH you can find all released versions of Alnuth at the package's homepage http://www.icm.tu-bs.de/ag_algebra/software/Alnuth/
in the form of gzipped tar-archives or as uncompressed tar-archives,
and starting with Version 3.0.0 also as zip archives for Windows. The
main page always contains the latest version of Alnuth, while older
versions can be found under
There are two ways of installing a GAP package. If you have
permission to add files to the installation of GAP on your system
you may install Alnuth into the
pkg subdirectory of the GAP
installation tree. Otherwise you may install Alnuth in a private
pkg directory (for details see Subsections Installing a GAP Package and GAP Root Directory in the GAP reference manual).
To install the latest version of Alnuth under Linux download one of
alnuth.tar.gz, move it to the
pkg in which you want to install, and unpack the
archive. If you are using the command line you can unpack the former
with the command
tar xf alnuth.tar, respectively
alnuth.tar.gz for the gzipped tar-archive.
For installation under Windows download the archive
move it to the
pkg directory in which you want to install, and
extract the archive (If you right click on the archive there should
appear a menu containing the entry
Using Alnuth requires an installation of PARI/GP in Version 2.5 or higher. The software PARI/GP is freely available at http://pari.math.u-bordeaux.fr/
Note that the place where PARI/GP is located in your system is independent of the place where Alnuth is installed.
In many Linux distributions PARI/GP can be installed via the software
package manager, but this might sometimes be an older version which
cannot be used together with Alnuth. (Starting GP from the command line
with the option
--version-short will show you the version number.)
If you install PARI/GP from source make sure you install with GMP
support for better performance and complete the installation with
make install so that you can start GP by just calling
gp from the
For Windows it is sufficient to get the basic GP binary which can be found at http://pari.math.u-bordeaux.fr/download.html
This package needs to know where the executable for GP is. In the
default setting Alnuth looks for an executable program named
the search paths of the system. More precisely, for a file
one of the directories in the list returned by
DirectoriesSystemPrograms() (called in a GAP session).
Under Linux the default setting should work with a standard installation of PARI/GP.
For the default setting to work under Windows the downloaded
executable file, for example
gp-2-5-0.exe has to be renamed to
gp.exe and moved to one of the directories listed by
DirectoriesSystemPrograms() (Ignore the leading
cygdrive in each
path name and note that the single letter specifies the drive, for
/cygdrive/c/Windows/ denotes the folder
Windows on drive
To check whether an executable of GP in Version 2.5 or higher is available with the default setting, you can use the function
which prints the verion number, if the global variable
is bound to the file name of a GP executable.
If you cannot use the default setting for you purpose, you have two options to specify a new place and name for the GP executable.
If you are able to edit the file
defs.g in the main directory of
Alnuth, then you can change the line
BindGlobal("AL_EXECUTABLE", Filename(DirectoriesSystemPrograms(), "gp"));to something like
BindGlobal("AL_EXECUTABLE", "/home/my/pari-2.5.0/gp");under Linux or
BindGlobal("AL_EXECUTABLE", "/cygdrive/c/Users/my/Downloads/gp-2-5-0");under Windows, where the second argument gives the path to the GP executable you want to use (Change the strings given above to reflect the actual path on your system.). Please note that in case of a new installation of Alnuth you will have to change
Alternatively you can also change your personal
gaprc file (see
the Subsection The gaprc file in the GAP reference manual)
for setting the variable AL_EXECUTABLE to a proper value. To do this
add the appropriate line from above with the
BindGlobal command to
The third possibility is to change the path to the GP executable from within GAP using one of the following two functions. To do this you first have to load the package (see Section Loading and testing the package).
adjusts the global variable
AL_EXECUTABLE for the current GAP
session. Depending on your installation of PARI/GP and your operating
system the string path has to be either the command to start GP in a
terminal (for example
gp) or the complete path to the executable of GP
/cygwindrive/c/windows/gp). The function returns
if path does not execute GP in Version 2.5.0 or higher.
To make the change take effect for all of your GAP sessions, you can
SetKantExecutable with the path to the GP executable as argument
to your personal
gaprc file (see the Subsection The gaprc file
in the GAP reference manual).
If you want the change to affect all GAP session of all users of the GAP installation you can use the following function:
does the same as
SetAlnuthExternalExecutable and in addition trys to
change the file
defs.g accordingly in the currently loaded version
of Alnuth. A warning is issued if there is no write access to
from the current GAP session.
trys to restore the original content of the file
defs.g in the
directory corresponding to the loaded version of Alnuth. The function
fail if there is no write access to
from the current GAP session.
If Alnuth is not loaded when GAP is started you have to request it
explicitly to use it. This is done by calling
in a GAP session. If Alnuth had not been loaded already a short
banner will be displayed.
gap> LoadingPackage("alnuth"); Loading Alnuth 3.0.0 ... true gap>To load a certain version of Alnuth you can specify the version number as second argument in the call to
77.2 Loading a GAP packagein the reference manual or type
?LoadPackagewithin a GAP session).
Once the package is loaded, it is possible to check the correct installation
running a short test by calling
gap> ReadPackage("Alnuth", "tst/testinstall.g"); Line 5 : + Test availability and version of PARI/GP Line 5 : + GAP4stones: 25000 Line 85 : + Installation test of Alnuth package Line 85 : + GAP4stones: 609 true gap>
The number of GAP4stones will usually differ; other discrepancies in the output indicate some problem.
If the test suite runs into an error in the first part, which verifies the availability of PARI/GP, check your installation of PARI/GP and consult the last chapter of the documentation of Alnuth for more information.
If you find any bugs or have any suggestions or comments, we would very much
appreciate it if you would let us know by writing to
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