This is the homepage of the Macaulay 2 package WeylGroups, written by Baptiste Calmès and Viktor Petrov, and dedicated to all sorts of computations involving root systems, Weyl groups, Bruhat order, etc.
You first need a working version of Macaulay 2, available freely from here, and you also need the package Graphics. Then, the package WeylGroups is installed by the standard procedure: for example, on a unix/linux or a Mac OS X system, unzip the package, lauch M2 from within the directory obtained, and within M2, type:
installPackage "WeylGroups"
This should install the package and the documentation files. This being done, the package can be loaded by typing:
loadPackage "WeylGroups"
in future M2 sessions.
All functions are documented in the usual Macaulay 2 documentation style and come with examples.
For example, to view the documentation corresponding to the whole package, type help "WeylGroups" or viewHelp "WeylGroups" to open it in your web browser.
A quick tutorial is then accessible from that main documentation page or by opening the file tutorial.html coming with the package.