% 1. get U of coarse-eles in this sub
% 2. rearange U as the order of scaled_fixeddofs
function ufixed = prepareU_scaled(edofMat_macro, U, sub_nelx, sub_nely, subx, suby, scalar)

    coarsex = subx/scalar;
    coarsey = suby/scalar;
    nely = sub_nely*scalar;
    ufixed = cell(sub_nely, sub_nelx);

    for subi = 1 : sub_nelx
        for subj = 1 : sub_nely

            us = zeros(2*(subx+1)*(suby+1), 1);

            for is = 1:scalar
                for js = 1:scalar
                    % which coarse element in the whole domain
                    jc = (subj-1)*scalar+js;
                    ic = (subi-1)*scalar+is;
                    ele = jc+(ic-1)*nely;

                    edof = edofMat_macro(ele,:);
                    ue = U(edof,:);
                    
                    % compute dofs of ue in this sub
                    last_col = (is-1)*coarsex;
                    this_col = (js-1)*coarsey + 1;

                    node4 = last_col*(suby+1) + this_col;
                    node1 = node4 + coarsey;
                    node3 = is*coarsex*(suby+1) + this_col;
                    node2 = node3 + coarsey;

                    dofs = [2*node1-1, 2*node1, 2*node2-1, 2*node2, ...
                            2*node3-1, 2*node3, 2*node4-1, 2*node4];
                    us(dofs,1) = ue;
                end
            end
            ufixed{subj, subi} = us;
        end
    end
end