public static float norm1(float[] x) {
        float norm = 0.0F;

        for (float n : x) {
            norm += abs(n);
        }

        return norm;
    }
@Test
    public void testNorm1_doubleArr() {
        System.out.println("norm1");
        double[] x = {-2.1968219, -0.9559913, -0.0431738, 1.0567679, 0.3853515};
        assertEquals(4.638106, MathEx.norm1(x), 1E-6);
    }