public Weibull(double lambda, double k) throws ParameterException {
		if (lambda <= 0 || k <= 0) {
			throw new ParameterException("Weibull parameters lambda, k > 0.");
		} else {
			this.lambda = lambda;
			this.k = k;
			unif = new ContinuousUniform(0, 1);
		}
	}