[lammps-users] How to do a 'per atom' assignment for a particle type (as a function of other per atom parameters)

Dear LAMMPS users,

I have a question about modifying parameters in LAMMPS, but I am not sure how to do it. My particular model is the SPH but it may be universal in other models and techniques:

In a system of three particle (atom) types, I’d like to change particle (atom) density of type 1, as a function of their energy through a set command. Since it is a ‘per atom’ assignment, so I did:

compute rho_peratom all meso/rho/atom
compute ie_peratom all meso/e/atom

What it troubles me is to:

set group water meso/rho c_rho_peratom*(1+c_ie_peratom/20)

Aiming to set c_rho_peratom of type 1 particles ( group water) as a function of c_ie_peratom. Obviously this is not working, so would you please tell me how I can implement it? Please note that particles are randomly distributed so I can not use n*m etc.

I would be glad to hear some suggestions and guidance.

Thanks in advance,

Amin Rahmat

what options you have is explained in the manual. so how about using an atom style variable?