#ifndef EXPONENTIAL_H
#define EXPONENTIAL_H

#include <cmath>
#include <random>

namespace Distribution {

	template <typename T> class Exponential {
		
		private:
	
			T lambda;
	
			std::minstd_rand gen;
			std::exponential_distribution<T> dist;
	
		public:
	
			/** ctor */
			Exponential(const T lambda) : lambda(lambda), gen(1234), dist(lambda) {
				;
			}
	
	
			/** get probability for the given value */
			T getProbability(const T val) const {
				return lambda * std::exp(-lambda * val);
			}
	
			/** get a normally distributed random number */
			T draw() {
				return dist(gen);
			}
	
			/** set the seed to use */
			void setSeed(const long seed) {
				gen.seed(seed);
			}
	
	
			/** get the probability for the given value */
			static double getProbability(const double lambda, const double val) {
				return lambda * std::exp(-lambda * val);
			}
	
		};
		
		
	};

}

#endif // EXPONENTIAL_H