def METHOD_NAME():
    """Build and test first order linear
    and time-invariant coeff. ds
    """
    time = 1.2
    ds_list = []
    b_vec = np.random.random((nn,))
    ds_list.append(sk.FirstOrderLinearTIDS(x0, a_mat))
    ds_list.append(sk.FirstOrderLinearTIDS(x0, a_mat, b_vec))
    for ds in ds_list:
        assert ds.isLinear()
        assert ds.dimension() == nn
        assert np.allclose(ds.x0(), x0)
        assert np.allclose(ds.x(), x0)
        assert np.allclose(ds.r(), 0.0)
        rhs = np.dot(a_mat, ds.x())
        if ds.b() is not None:
            rhs += ds.b()
        ds.initRhs(time)
        assert np.allclose(rhs, ds.rhs())
        assert np.allclose(ds.jacobianRhsx(), a_mat)
        assert np.allclose(ds.jacobianRhsx(), ds.jacobianfx())