private Gamma() {

    }
@Test
    public void testGamma() {
        System.out.println("gamma");
        assertTrue(Double.isInfinite(Gamma.gamma(0)));

        assertEquals(1.0, Gamma.gamma(1), 1E-7);
        assertEquals(1.0, Gamma.gamma(2), 1E-7);
        assertEquals(2.0, Gamma.gamma(3), 1E-7);
        assertEquals(6.0, Gamma.gamma(4), 1E-7);

        assertEquals(0.886227, Gamma.gamma(1.5), 1E-6);
        assertEquals(1.329340, Gamma.gamma(2.5), 1E-6);
        assertEquals(3.323351, Gamma.gamma(3.5), 1E-6);
        assertEquals(11.63173, Gamma.gamma(4.5), 1E-5);
    }