Computational Physics, Python, Math, Physics.
+ Cx2*(q[i,1:N_y -1] + q[i+1,1:N_y -1])*(u_n[i+1,1:N_y -1] - u_n[i,1:N_y -1]) + Cy2*( 0.5*(q[i,1:N_y -1] + q[i,2:N_y])*(u_n[i,2:N_y] - u_n[i,1:N_y -1]) - 0.5*(q[i,0:N_y -2] + q[i,j])*(u_n[i,1:N_y -1] - u_n[i,0:N_y -2]) ) j = 0 u_np1[1:N_x - 1,j] = 2*u_n[1:N_x - 1,j] - u_nm1[1:N_x - 1,j] + Cx2*(