%--------------------------
 % @Author: Jingqiao Hu
 % @Date: 2021-12-11 20:06:32
 % @LastEditTime: 2021-12-11 20:06:32
%--------------------------
function [sK_cell, area_cell, area0, local_area] = prepare_sK(nodes_cell, faces_cell, e1, nu)

    ncvt = size(faces_cell, 1);
    sK_cell = cell(ncvt, 1);
    area_cell = cell(ncvt, 1);

    area0 = 0; % the area of all domain
    local_area = zeros(ncvt, 1);

    parfor ele = 1 : ncvt
        nodes = nodes_cell{ele};
        faces = faces_cell{ele};
        [sK, area] = intKE_triangle(nodes, faces, e1, nu);

        sK_cell{ele} = sK;
        area_cell{ele} = area;

        area0 = area0 + sum(area);
        local_area(ele) = sum(area);
    end

    local_area = local_area / max(local_area);
end