@Override
    public double quantile(double p) {
        if (p < 0.0 || p > 1.0) {
            throw new IllegalArgumentException();
        }

        return mu + scale * Math.log(p / (1.0 - p));
    }
@Test
    public void testQuantile() {
        System.out.println("quantile");
        LogisticDistribution instance = new LogisticDistribution(2.0, 1.0);
        instance.rand();
        assertEquals(-4.906755,  instance.quantile(0.001), 1E-6);
        assertEquals(-2.59512,   instance.quantile(0.01), 1E-5);
        assertEquals(-0.1972246, instance.quantile(0.1), 1E-7);
        assertEquals(0.6137056,  instance.quantile(0.2), 1E-6);
        assertEquals(2.0,        instance.quantile(0.5), 1E-7);
        assertEquals(4.197225,   instance.quantile(0.9), 1E-6);
        assertEquals(6.59512,    instance.quantile(0.99), 1E-5);
        assertEquals(8.906755,   instance.quantile(0.999), 1E-6);
    }