Set constant velocity and density

I want to set constant velocity and density afte each collision and streaming for some nodes inside the domain in PALABOS. can anybody help regarding this issue.
Thanks, Navid Samiei`

I guess the function initializeAtEquilibrium() is what you want. It can not only be used during the initialization, but also for each time step after (or before) the lattice.collideAndStream().

thank for answering, but you know if I use this function I should set rho and velocity values for all nodes but I just want to change 2 nodes velocity and density