A Self Interacting Warm Dark Matter (SIWDM) extension module built on top of CLASS (https://github.com/lesgourg/class_public) version 2.7.2
Simply run bash install.sh on a linux terminal. This will create a folder called class_public-2.7 which contains the modified code. Make sure that you have the python command bound to a version of python 2.7.x. In addition, you would want to have another version of python 3.x to run the relaxation time calculator
The code itself can be run through command line, using ./class ini_file.ini pre_file.pre. The .ini file contains all the inizialization cosmology parameters, while the .pre contains precision and other internal code variables.
We reccomend taking a look at explanatory_plus_siwdm.ini for further information about possible options.
Output is directed to the /output directory, where you can find power spectra, Cl, etc.
The install script also installs a custom class Class for importing from the module classy onto python 2.7.x. You can find a straightforward appication of this in a supplied python script Simple_SIWDM_PS.py, where it is used to calculate a (low-resolution) power spectra comparison between CDM, WDM and SIWDM.
You can find a relaxation time calculator in the file reltime.py, in order to create custom runs with arbitrary coupling constants (requires python 3.x). Refer to the documentation in the file itself for instructions on its usage.