[GAP Forum] using GAP in SAGE

[David Joyner]

Hello GAP people:

Here are instructions for using GAP within SAGE, a newish computer
algebra system written mostly by WIlliam Stein which uses the ipython
shell. These instructions only purtain to linux/unix computers. (If you
have a windows
computer, you must install cygin and keep your fingers crossed:-)

SAGE now includes GAP in its distribution, as well as Singular. Although
SAGE really
stands for System for Algebra and Geometry Exploration, it could also
abbreviate Singular And Gap Encorporated:-)


I will assume you want to compile from source. Binary versions might be
easier to install (see http://modular.ucsd.edu/SAGEbin/).

1. Download the latest version of SAGE from
http://modular.ucsd.edu/sage/dist/src/index.html
or
http://sage.sourceforge.net/dist/src/index.html

2. Follow the steps in http://modular.ucsd.edu/sage/doc/html/inst/node3.html
These are:
untar the file in a directory, thus creating a directory sage-0.9.6 (say).
cd to that directory (eg, enter "cd sage-0.9.6")
type "make"

This may take 30 minutes or so to compile.

3. Download http://sage.sourceforge.net/packages/optional/gap-gpl.spkg
and save to the directory sage-0.9.6. Type

./sage -i gap-gpl.spkg

This loads the GAP GPL'd packages DESIGN, FactInt,
GAPDoc, GRAPE, GUAVA, LAGUNA, and TORIC . It also
compiles (automatically) the C programs in guava and grape.

Now type

./sage -i database_gap-4.4.6

this loads the table of marks and the small groups library.


4. Start SAGE by typing ./sage on the command line and at the sage prompt.
You must create a GAP workspace. For example, if you want to create a
workspace of 750M and with guava and laguna preloaded, type at the SAGE
prompt:

gap('LoadPackage("guava")')
gap('LoadPackage("laguna")')
gap_reset_workspace(750)

For the default, just use gap_reset_workspace().

Now exit SAGE by typing ctl-D.

5. All GAP (and guava and laguna) commands are now available by typing
gap('my favorite gap command'). Examples are at
http://sage.sourceforge.net/examples/sage-constructions/node4.html
or
http://modular.ucsd.edu/sage/doc/html/prog/node7.html
or
http://modular.ucsd.edu/sage/doc/html/ref/module-interfaces.gap.html
You can even use SAGE to interface between Singular and GAP:
http://modular.ucsd.edu/sage/doc/html/ref/node7.html

Have fun!

- David Joyner