gitfanlib  a package for GITfans
(for Maple or polymakeSingular or Singular 3.1.6)
Current version: (May / October / November, 2012),
Software Systems
At the moment there are versions for

Maple by Simon Keicher (requires Maple 10 or above
and the package
convex
by Matthias Franz).

polymake/Singular by Simon Keicher and Thomas Kremer (The Polymake/Singularversion of gitfanlib needs at least polymake 2.11 and Singular 3.1.3 installed),

Singular 3.1.6 by Janko Böhm, Simon Keicher and Yue Ren (requires at leat Singular 3.1.6).
There also is an early first Macaulay2implementation here.
Description
Given the action of a torus \( H \) on an affine variety \( X\), this package provides functions to compute
 GITchambers,
 the GITfan of the \(H\)action on \(X\),
 toric orbits intersecting \(X\).
We assume that \(X\) is given by equations and \(H\) is given by a grading matrix.
Installation
 Mapleversion: Download the files
gitfanlib.ind
and
gitfanlib.lib,
and put them into a directory where Maple can find them.
In a new Maplesession enter "with(gitfanlib);" after loading convex.

polymake/Singularversion: Download the current version and load the extension in polymake by using the command 'found_extension('pathtofolder')'.

Singularversion: download gitfan.lib and load it in Singular by using the command 'LIB "gitfan.lib"'.
Documentation
There is a manual for the Mapleversion. For the other versions: please refer to the respective README file.
updated: November 19, 2012