public void DigammaInvTest() { for (int i = 0; i < 1000; i++) { double y = -3 + i * 0.01; double x = MMath.DigammaInv(y); double y2 = MMath.Digamma(x); double error = MMath.AbsDiff(y, y2, 1e-8); Assert.True(error < 1e-8); } }