4  1.d-6  1000  1.d0  ! n, tol, maxit , w
12.d0  34.d0  27.d0  -38.d0  ! b(i)
6.d0 -2.d0 2.d0 4.d0 ! a(1,j)
12.d0 -8.d0 6.d0 10.d0  ! a(2,j)
3.d0 -13.d0 9.d0 3.d0  ! a(3,j)
-6.d0 4.d0 1.d0 -18.d0  ! a(4,j)