xCoba: General component tensor computer algebra
Authors: David Yllanes and José M. Martín-García, © 2005-2015 under GPL.
xCoba, a companion package to xTensor, provides several tools for
working with bases and components. It allows the user to define bases
on one or more manifolds and to handle basis vectors, using basis
indices notation. It performs component calculations such as expanding
a tensor in a specified basis, changing the basis of an expression or
tracing the contraction of basis dummies. The package knows how to
express derivatives and brackets of basis vectors in terms of
Christoffel and torsion tensors and how to assign values to the
components of a tensor. Support for charts (coordinate fields,
restriction of a field to a point, etc.) is still limited.
Download and installation
Current version: 0.8.3 (as of 23 August 2015). It is recommended to download the main xAct bundle, but you can also download the different files separately:
- xCoba.nb: source file with all definitions and comments. Many examples. You need this file if you want to understand and/or modify the internals of the package. This is almost a Reference file.
- xCoba.m: package file. This file is automatically generated by Mathematica when xCoba.nb is saved. This is the only essential file.
- xCobaDoc.nb: main documentation file.
- General Public License
See the Installation notes.