public void ValidateDensity(double scale, double shape, double x, double expected)
{
var dist = new Pareto(scale, shape);
Assert.AreEqual(expected, dist.Density(x), 1e-12);
Assert.AreEqual(expected, Pareto.PDF(scale, shape, x), 1e-12);
Assert.AreEqual(Math.Log(expected), dist.DensityLn(x), 1e-12);
Assert.AreEqual(Math.Log(expected), Pareto.PDFLn(scale, shape, x), 1e-12);
}