@Override
    public double logp(double x) {
        return Math.log(p(x));
    }
@Test
    public void testLogP() {
        System.out.println("logP");
        LogisticDistribution instance = new LogisticDistribution(2.0, 1.0);
        instance.rand();
        assertEquals(Math.log(0.1050736), instance.logp(0.001), 1E-5);
        assertEquals(Math.log(0.1057951), instance.logp(0.01), 1E-5);
        assertEquals(Math.log(0.1131803), instance.logp(0.1), 1E-5);
        assertEquals(Math.log(0.1217293), instance.logp(0.2), 1E-5);
        assertEquals(Math.log(0.1491465), instance.logp(0.5), 1E-5);
        assertEquals(Math.log(0.1966119), instance.logp(1.0), 1E-5);
        assertEquals(Math.log(0.25),      instance.logp(2.0), 1E-5);
        assertEquals(Math.log(0.04517666), instance.logp(5.0), 1E-5);
        assertEquals(Math.log(0.0003352377), instance.logp(10.0), 1E-5);
    }