class Mixture implements MultivariateDistribution {

    @Override
    public double density(RealVector vector) {
        double d = 0;
        for (int i=0; i< components.size(); i++) {
            d += components.get(i).density(vector) * weights[i];
        }
        return d;
    }

    public  Mixture(List<MultivariateDistribution> components, double[] weights);

}