xAct-contrib

This is a collection of the community-contributed code for the xAct tensor algebra package for Mathematica, which can be downloaded here. The best place to go for questions is the xAct mailing list. You can find our repositories at @xAct-contrib on github. If you have contributions, feel free to send pull requests.

Contributions

Larger contributions:

• pncbc-eftofpng from @miche-levi (Michele Levi)
• Spinors from @wtbgagoa (Alfonso García-Parrado)
• xTras from @teake (Teake Nutma)
• TexAct from Thomas Bäckdahl and @barrywardell (Barry Wardell)
• xPand from Cyril Pitrou, Xavier Roy, and @Obinna (Obinna Umeh)
• xIST/COPPER from @noller (Johannes Noller)
• xPrint from @magmagithub (Alessandro Stecchina) (web page)
• xTerior from @wtbgagoa (Alfonso García-Parrado) and @duetosymmetry (Leo Stein)

Smaller contributions:

• xAct examples, a collection of common usage patterns and some notebooks from the mailing list
• TraceFree, an xTension for defining tensors to have vanishing traces. From @duetosymmetry (Leo Stein)
• DivFree, an xTension for defining tensors to have vanishing divergences. From @duetosymmetry (Leo Stein)
• HelloWorldxTension, a tiny xTension example to use as a template

Creating an xAct package

If you've never built a Mathematica package before, this might seem a little daunting. That's why we've provided a “Hello World” template/example package named HelloWorldxTension. This example covers the overhead of dependencies, scope, etc. and shows how to use xTension to add a message to print from DefTensor.