wolffd@0: function [A1, A2, B1, B2, C11, C12, C21, C22] = partition_matrix_vec_3(A, B, C, n1, n2, bs)
wolffd@0: 
wolffd@0: dom = myunion(n1, n2);
wolffd@0: n1i = block(find_equiv_posns(n1, dom), bs(dom));
wolffd@0: n2i = block(find_equiv_posns(n2, dom), bs(dom));
wolffd@0: 
wolffd@0: 
wolffd@0:     A1 = A(n1i);
wolffd@0:     A2 = A(n2i);
wolffd@0:     if isempty(B)
wolffd@0:         B1 = zeros(size(n1i, 2),size(B, 2));
wolffd@0:         B2 = zeros(size(n2i, 2),size(B, 2));
wolffd@0:     else
wolffd@0:         B1 = B(n1i, :);
wolffd@0:         B2 = B(n2i, :);
wolffd@0:     end
wolffd@0:     
wolffd@0:     
wolffd@0:     C11 = C(n1i, n1i);
wolffd@0:     C12 = C(n1i, n2i);
wolffd@0:     C21 = C(n2i, n1i);
wolffd@0:     C22 = C(n2i, n2i);