public void ValidateDensityLn(double location, double scale, double x)
{
var n = new Laplace(location, scale);
double expected = -Math.Log(2.0 * scale) - (Math.Abs(x - location) / scale);
Assert.AreEqual(expected, n.DensityLn(x));
Assert.AreEqual(expected, Laplace.PDFLn(location, scale, x));
}