MathGR is a package for GR calculation, written in Mathematica.
The manual of the package is available at http://arxiv.org/abs/1306.1295
Note: if you download (instead of clone) the package and then unzip, the folder name will include a version number, something like
MathGR-0.1.1. Please change it to exactly
MathGR before usage. This is because
Mathematica requires the folder name to be exactly the same as the package name. Otherwise the packages cannot be properly loaded.