Category: News

Version 0.2.3 released

Posted by – May 22, 2012

Version 0.2.3 of Pyflation has been released and is available on the downloads page and via PyPI using pip install or easy_install.

This release fixes a major issue for multi-field models in which the nfields parameter would not be passed to model instances causing failure of model runs. The commit for the necessary change is viewable on Bitbucket.

Version 0.2.2 released

Posted by – May 3, 2012

I have just added the latest version of Pyflation to the Downloads page. Version 0.2.2 has minor improvements to the command line options for pyflation_firstorder and now includes the C files generated by Cython. Hopefully this means that installing from the Python Package Index will now work.


$ pip install pyflation


$ easy_install pyflation

to download and install from PyPi. You will need to have installed all the requirements beforehand.

The code for this update is also now available on the Bitbucket repository.

Git repository now available

Posted by – February 28, 2012

If you are a developer who would like to fork the Pyflation code, there is now a git repository available on Bitbucket. To clone the code to your local machine use:
$ git clone

The main branch of the code is available on the Bitbucket repository up until version 0.2.1. There is also an issue tracker if you have any problems to report.

Version 0.2.1 released

Posted by – February 16, 2012

The latest version of Pyflation is now available from the Downloads page and on the Python Package Index.

In this version there are many improvements in the documentation, and there are now docs available online.

Version 0.2 released

Posted by – November 30, 2011

A new version of Pyflation has been released! Get it from the Downloads page or right here.

Version 0.2.0 adds many new features including multi-field evolution of first order perturbations. Source term generation and therefore second order evolution are still only possible for single field models for now. Each model instance now has a nfields variable which is passed to the potential function. New two field and n-field potentials have been added to the cmpotentials module.

Another new feature is the analysis package which encapsulates functions to calculate power spectra of adiabatic and isocurvature perturbations and calculate the spectral indices for these quantities. This package features extensive unit test coverage (in the test directory) and has been used to create the results for a new submission to the arXiv.

Paper now on the arXiv

Posted by – March 7, 2011

The paper accompanying the first release of the Pyflation package is now available on the arXiv preprint server. The tite and abstract of the paper are:

Second Order Perturbations During Inflation Beyond Slow-roll

Ian Huston, Karim A. Malik

We numerically calculate the evolution of second order cosmological perturbations for an inflationary scalar field without resorting to the slow-roll approximation or assuming large scales. In contrast to previous approaches we therefore use the full non-slow-roll source term for the second order Klein-Gordon equation which is valid on all scales. The numerical results are consistent with the ones obtained previously where slow-roll is a good approximation. We investigate the effect of localised features in the scalar field potential which break slow-roll for some portion of the evolution. The numerical package solving the second order Klein-Gordon equation has been released under an open source license and is available for download.

If you want to cite this paper the BiBTeX is

author         = “Huston, Ian and Malik, Karim A.”,
title          = “{Second Order Perturbations During Inflation Beyond
year           = “2011″,
eprint         = “1103.0912″,
archivePrefix  = “arXiv”,
primaryClass   = “astro-ph.CO”,
There are other versions of the bibliographic information available on the Inspire Beta listing.