Welcome to the CTM module’s documentation!

The Cosmological Trajectories Method (CTM) is a perturbative technique to compute the power spectrum and two-point correlation function in real space in the mildly to non-linear regime for a range of cosmologies.

Source and installation

The code is available at Github but can also be installed using pip (all of the dependencies will be automatically installed)

pip install ctmmodule

If pip fails to install classylss please follow the following conda instructions and then retry the installation of the CTM module using pip.

To install the code from source, first run the following

pip install mcfit
pip install classylss
git clone https://github.com/franlane94/CTM

Then navigate to your .bash_profile (or .profile on Linux machines) and add the following line

export PYTHONPATH="$PYTHONPATH:/DIRECTORY_WHERE_CTM_IS_INSTALLED"

To check the module has been installed correctly run

python
from ctm import CTM

Getting started

For a quick start please see the Jupyter notebook. For more detailed examples and information about the code please see the documentation pages.

The default cosmology is Planck18 and the values of key parameters shown in the Table below.

Parameter

Value

\(H_0\)

67.66

\(\Omega_{cdm}h^2\)

0.1193

\(\Omega_{b}h^2\)

0.0224

\(n_s\)

0.9665

\(\sigma_8\)

0.8102

Note

The units of commonly used variables in this code are:

  • \(H_0\ [\mathrm{km}\ \mathrm{s}^{-1}\ \mathrm{Mpc}^{-1}]\)

  • \(k\ [\mathrm{h}\ \mathrm{Mpc}^{-1}]\)

  • \(\mathrm{P}\left(k\right)\ [\mathrm{Mpc}^3\ \mathrm{h}^{-3}]\)

  • \(r\ [\mathrm{Mpc}\ \mathrm{h}^{-1}]\)

Citation

The CTM module is described in Lane et al. 2021 , if you make use of the CTM module, please include a citation to this work in any publications.

Acknowledgements

Please also cite the following papers whose work has featured in the development of both the CTM and this Python module:

Help and issues

If you encounter any issues please either use the Github issues page, or email ctmcodehelp@gmail.com.