%--------------------------
 % @Author: Jingqiao Hu
 % @Date: 2022-01-27 13:04:55
 % @LastEditTime: 2022-01-27 14:58:42
%--------------------------
function [iK, jK, edofMat] = forAssemble_tetmesh(tets)

    nele = size(tets, 1);

    edofMat0 = [3*tets-2, 3*tets-1, 3*tets]; % 12 cols [x1,x2,x3,x4,y1,y2,y3,y4,z1,z2,z3,z4]
    edofMat  = edofMat0(:, [1,5,9,2,6,10,3,7,11,4,8,12]); 

    iK = reshape(kron(edofMat,ones(12,1))',12*12*nele,1);
    jK = reshape(kron(edofMat,ones(1,12))',12*12*nele,1);
end