Poisson distribution returns -1.0 for very small values of lambda #1428
Description
With rand_distr = "0.4.3" and rand = "0.8.5" I was able to sample -1.0 by providing small enough values of lambda.
use rand_distr::{Distribution,Poisson};
use rand::thread_rng;
fn main() {
let poisson_dist: Poisson<f32> = Poisson::new(0.0000000002).unwrap();
println!("{:?}", poisson_dist.sample(&mut thread_rng()));
let poisson_dist: Poisson<f64> = Poisson::new(0.0000000000000000002).unwrap();
println!("{:?}", poisson_dist.sample(&mut thread_rng()));
}