%--------------------------
 % @Author: Jingqiao Hu
 % @Date: 2021-03-13 16:46:15
 % @LastEditTime: 2021-03-13 17:06:48
%--------------------------
function psi = energy_1scale(F, eleNum, global_u, global_l, dx)
    psi = 0;
    jac = dx^2/4;
    for gp = 1:4 
        Fg = F{gp};
        for ele = 1:eleNum        
            Fe = reshape(Fg(:, ele), 2, 2);
            psi = psi + energy_local(Fe, global_u(ele), global_l(ele))*jac;
        end
    end
end

function psi = energy_local(F, u, l)
    epsilon = (F + F')/2 - eye(2);
    psi = u * sum(sum(epsilon.^2)) + l/2 * trace(epsilon)^2;
end