class ExponentialDistribution extends AbstractRealDistribution {

    public double cumulativeProbability(double x)  {
        double ret;
        if (x <= 0.0) {
            ret = 0.0;
        } else {
            ret = 1.0 - FastMath.exp(-x / mean);
        }
        return ret;
    }

    public  ExponentialDistribution(double mean);
    public  ExponentialDistribution(double mean, double inverseCumAccuracy);
    public  ExponentialDistribution(RandomGenerator rng, double mean);
    public  ExponentialDistribution(RandomGenerator rng,
                                   double mean,
                                   double inverseCumAccuracy);

}