%--------------------------
 % @Author: Jingqiao Hu
 % @Date: 2020-10-29 15:04:15
 % @LastEditTime: 2021-01-10 10:17:57
%--------------------------
function [usol] = micro_FEA_KUBC(nelx, nely, iK, jK, inner, outer, ufixed, xPhys, KE0, KE1)

    sK = zeros(64, nelx*nely);
    for ele = 1:nelx*nely
        if xPhys(ele)==1
            sK(:, ele) = KE1(:);
        else
            sK(:, ele) = KE0(:);
        end
    end
    sK = sK(:);

    % sK = reshape(KE(:) * (Emin + xPhys(:)' * (E0 - Emin)), 64 * nelx * nely, 1);
    K = sparse(iK, jK, sK); 
    K = (K + K') / 2;
    
    umicro = zeros(size(ufixed));
    
    % uouter = ufixed';
    % uouter = uouter(:);
    Fr = -K(inner, outer) * ufixed(outer, :);
    umicro(inner, :) = K(inner,inner) \ Fr;
    usol = umicro + ufixed;   
end