%--------------------------
 % @Author: Jingqiao Hu
 % @Date: 2021-11-26 09:23:33
 % @LastEditTime: 2021-11-28 15:25:27

 % sK is [nedofs, nele]
%--------------------------
function [K] = assemble_micro_k_hetero(dofid, rho_e, e0, e1, penal, sK0, iK, jK)
    
    new_iK = dofid(iK);
    new_jK = dofid(jK);
    
    sK = sK0 .* (e0 + rho_e(:)'.^penal * (e1 - e0)); % [nedofs, nele]

    K = sparse(new_iK, new_jK, sK(:)); 
    K = (K + K') / 2;
end