public static double logNormalThreeParPDF(double alpha, double beta, double gamma, double x) {
		if (beta < 0) throw new IllegalArgumentException("The parameter beta, " + beta + ", must be greater than or equal to zero");
		if (x <= alpha) {
			return 0.0D;
		} else {
			return Math.exp(-0.5D * Fmath.square(Math.log((x - alpha) / gamma) / beta)) / ((x - gamma) * beta * Math.sqrt(2.0D * Math.PI));
		}
	}