natural convection 2D square cavity_Adiabatic walls

Hello LBM Friends;Hope you’re doing well!!
Well;i am simulating Natural convection in square cavity using a Matlab code based on LBM :left wall(hot)/right wall(cold)/top wall and bottom one are both adiabatic i am using D2Q5 Model for temperature ;here are the boundary conditions for temperature i am using for adiabatic walls:

tIn(5,2:lx-1,ly) = (4tIn(3,2:lx-1,ly-1) -tIn(3,2:lx-1,ly-2))/3;
tIn(3,2:lx-1,1) = (4
tIn(5,2:lx-1,2) -tIn(5,2:lx-1,3))/3;

please tell me if any mistakes are there?
Thank you