Guidelines for the Implementation of Different Dark Energy Models in CLASS
- Download the latest version of CLASS from the official GitHub repository.
- In section 8a of the explanatory.ini file, fix Omega_Lambda, and Omega_scf equal to zero, in order to avoid any contribution from the cosmological constant or a scalar field, and comment out the option Omega_fld.
- Enter the include folder.
- Locate the background.h file, and specify inside the struct background loop the variable type of the considered dark energy model.
- Enter the source folder.
- In the file background.c include any necessary extra libraries, and either include a new section in the code with your model (similar to those implemented for the default parametrizations), or modify the functions *w_fld, *dw_over_da_fld and *integral_fld of the default CPL model for simplicity.
- In the input.c file inside the if(pba→fluid_equation_of_state=”model_name”) routine include the dark energy variables, and in the section background structure store the default values of the extra parameters of your dark energy model.
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