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xPand: Computer algebra for cosmological perturbation theory

Authors: Cyril Pitrou, Xavier Roy, Obinna Umeh, © 2012-2021 under GPL.

Article: C. Pitrou, X. Roy and O. Umeh, Class. Quant. Grav. 30 (2013) 165002, arXiv: 1302.6174.


This is a package for the computation of perturbation equations around a homogeneous cosmological background. It is based on a 3+1 splitting of the background space-time. It admits all types of homogeneous background, from Friedmann-Lemaître to Bianchi type space-times, and allows for any choice of gauge.

Download and installation

Current version: 0.4.3 (as of 4 March 2019). The tarball containing the package, the documentation and examples can be downloaded from xPand's website.