Implement an interface to GAP3

[saliola]

It would be great to have an interface to GAP3 so that one can use GAP3 packages that have not been ported to GAP4. Of particular interest are the packages (sage-devel occasionally receives questions about integrating these packages):

• CHEVIE: Finite reflection groups and their root systems, braid groups, Iwahori-Hecke algebras, and Kazhdan-Lusztig polynomials.
• Specht: Specht: Decomposition matrices for the Hecke algebras of type A.

For a list of other GAP3 packages, check out

http://www.gap-system.org/Gap3/Packages3/packages.html

To use the interface implemented in this ticket, you need to have GAP3 installed on your machine.

To this end, you can use Jean Michel's GAP3 distribution
http://www.math.jussieu.fr/~jmichel/gap3/gap3-jm4.tar.gz
(instructions: http://www.math.jussieu.fr/~jmichel/gap3), which
includes a bunch of GAP3 packages (including Chevie, Specht, ...),

A simple alternative is to install the following Sage package
based on a slightly outdated version of the above.

    sage -i http://sage.math.washington.edu/home/nthiery/gap3-jm2.spkg

CC: @sagetrac-sage-combinat @wdjoyner @seblabbe @sagetrac-jmichel

Component: interfaces

Keywords: gap3, chevie, specht, gap, sage-combinat

Author: Franco Saliola

Reviewer: Burcin Erocal

Merged: sage-4.4.4.alpha1

Issue created by migration from https://trac.sagemath.org/ticket/8380

[saliola]

Description changed:

--- 
+++ 
@@ -3,6 +3,8 @@
 * CHEVIE: Finite reflection groups and their root systems, braid groups, Iwahori-Hecke algebras, and Kazhdan-Lusztig polynomials. 
 * Specht: Specht: Decomposition matrices for the Hecke algebras of type A.
 
-For a list of other GAP3 packages, check out [http://www.gap-system.org/Gap3/Packages3/packages.html](http://www.gap-system.org/Gap3/Packages3/packages.html).
+For a list of other GAP3 packages, check out
+
+  [http://www.gap-system.org/Gap3/Packages3/packages.html](http://www.gap-system.org/Gap3/Packages3/packages.html)
 
 To be clear, I am not suggesting distributing GAP3 with Sage. This would be just an to GAP3.

[saliola]

comment:2

Here are two patches. Make sure you apply the correct patch for you version of Sage.

Of course, you need to have GAP3 installed in order to use GAP3, and all doctests are marked optional.

The interface behaves very much like the GAP4 interface: tab completion works, one can access the GAP3 help documentation, etc.

Notes for the reviewer:

1. To run the GAP3 doctests:

   sage -testall -only-optional=gap3
   

2. I refactored the GAP4 interface code; basically, I separated the Gap class into two new classes Gap_generic and GapElement_generic.

3. I've tested that the patches apply cleanly and all doctests pass on the following systems:

   a. sage.math
   b. Ubuntu 9.10, amd 64

[saliola]

IGNORE THIS PATCH

[saliola]

comment:3

Attachment: gap3_interface_v4.3.2.2.patch.gz

This updated patch catches GAP3's syntax error messages.

The interface seems pretty robust now, so its ready for review. Please try it out.

[saliola]

Attachment: gap3_interface_v4.3.2.patch.gz

Patch for Sage version 4.3.2 only.

[saliola]

Attachment: gap3_interface_v4.3.3.patch.gz

Patch for Sage version 4.3.3 only.

[saliola]

Documentation

[saliola]

comment:4

Attachment: gap3_interface_doc.pdf.gz

If you're a GAP3 user interested in trying the new interface, then you can follow the instructions below to patch your version of Sage. These instructions are just a summary of the procedure described at: http://www.sagemath.org/doc/developer/walk_through.html#reviewing-a-patch. (Alternatively, your can just install all the sage-combinat patches using the command "sage -combinat install", which includes the GAP3 interface patch.)

1. First, create a branch of your Sage library (you can later switch between the main branch and the new gap3 branch with the commands "sage -b main" and "sage -b gap3"):

   sage -clone gap3
   

2. Next, start Sage and run one of the following commands, depending on the version of Sage you have installed.

* For sage-4.3.2:

sage: hg_sage.apply("https://github.com/sagemath/sage-prod/files/10648296/gap3_interface_v4.3.2.patch.gz")

* For sage-4.3.3:

sage: hg_sage.apply("https://github.com/sagemath/sage-prod/files/10648297/gap3_interface_v4.3.3.patch.gz")

3. Finally, exist Sage and run the following command.

sage -br

You should be up and running now.

I've also generated the documentation and posted it as a PDF file. You can find it in the "Attachments" section.

[saliola]

comment:5

Nicolas Thiery has posted some code on the sage-combinat patch server that uses this interface to construct Coxeter groups using the GAP3 package CHEVIE. Here is a link to his code: http://combinat.sagemath.org/hgwebdir.cgi/patches/file/e800cdb481fb/trac_8359-coxeter-groups-permutation-nt.patch#l1

[seblabbe]

comment:6

I tested it on my sage-4.3.3 running mac OS X 10.5.8. I had already the gap3 together with the chevie package. With the patch applied, I obtain All test passed! with the command sage -t -long. I also obtain All test passed with the command sage -testall -only-optional=gap3. The documentation builds without warning and is very complete.

Before giving a positive review, I would like one person used with interface code to take a look at the patch.

Good work Franco!