Python CAMB

CAMB (Code for Anisotropies in the Microwave Background), a cosmology code for calculating CMB, lensing, galaxy count, dark-age 21cm power spectra, matter power spectra and transfer functions. There are also general utility function for cosmological calculations. The main code is Python with numerical calculations implemented efficiently in Python-wrapped modern Fortran.

See the CAMB python example notebook for a quick introductory set of examples of how to use the CAMB package.

For a standard non-editable installation use:

pip install camb [--user]

The –user is optional and only required if you don’t have write permission to your main python installation. To install from source, in the project source root directory use:

python install [--user]

If you want to work on the code, you can also just install in place without copying anything using:

python make
pip install -e . [--user]

You will need gfortran 6 or higher installed to compile. Binary files for Windows are also provided, so these are used instead if no gfortran installation is found on Windows machines. If you have gfortran installed, “python make” will build the Fortran library on all systems (including Windows without directly using a Makefile).

After installation the camb python module can be loaded from your scripts using “import camb”. You can also run CAMB from the command line reading parameters from a .ini file, e.g.:

camb inifiles/planck_2018.ini

You may need to check your python scripts directory is in your path for this to work. Alternatively from the source package root directory (after make but without installation) use:

python inifiles/planck_2018.ini

Main high-level modules:

Other modules: