CosmoCoffee

I am trying to modify the camb code for strongly interacting MASSLESS neutrino ..
I want to keep only first two momments .That is , I want to truncate all momments except the density and velocity ones . Can anyone help me which file /files to modify ...
I have just started using CAMB a week ago . So sorry if I asked a naive question

The neutrino hierarchies are evolved in equations.f90 along with the other components. You can probably manually set the higher moments to zero, or, preferably, use a physical model for how this happens.