function bdmatrix(a)global LA DAE LA.b_statcom = [];  LA.d_statcom = [];  if ~a.n  fm_disp('* * * No Statcom device found')  returnendFu = sparse(DAE.n,a.n);Gu = sparse(a.vref,1:a.n,a.u,DAE.m,a.n);% B & D matrix for reference voltageLA.d_statcom = -full(DAE.Gy\Gu);LA.b_statcom = full(Fu + DAE.Fy*LA.d_statcom);