Modifying Friedmann equations in CAMB

[John Wick]

Hi all

I have a set of modified Friedmann equations and I would like to modify camb code to implement those modification and then use cobaya to constrain the parameters. Where can I add the modification to Friedmann equations in camb code. It would be great if somebody can help me with this.

[Antony Lewis]

Modify the functions in equations.f90.

Of course, if you only modify the background equations you cannot get consistent results for perturbations, only simple background things like H(z).