NormalRandom.hpp

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/*
Normal Random Distribution Header File
 
Author: Alex Reynolds
*/
#ifndef NORMAL_RANDOM_HPP
#define NORMAL_RANDOM_HPP
 
#include <random>
 
#include "data_management/GraphTreeObject.h"
#include "data_management/DataIO.hpp"
 
namespace modelspace {
 
    /**
     * @brief   Class to generate random numbers according to normal distribution
     * 
     * This function generates a random normal distribution draw according to
     * the mt19937 engine and a std::normal_distribution. It produces random
     * numbers according to the mean, std, and seed set in the constructor. Mean 
     * and std may be modified via standard setters mean and std.
    */
    template<typename T>
    class NormalRandom : clockwerk::GraphTreeObject {
    public:
        /// @brief Constructor for the normal random distribution
        /// @param mean The mean for the distribution
        /// @param std The standard deviation of the distribution
        /// @param seed Seed for the RNG -- Defaults to zero
        NormalRandom(T set_mean, T set_std, unsigned int seed = 0);
        ~NormalRandom() {}
 
        T operator () ();
 
        /// @brief The mean of the random output. Can be get/set
        clockwerk::DataIO<T> mean = clockwerk::DataIO<T>(this, "mean");
 
        /// @brief The standard deviation of the random output. Can be get/set
        clockwerk::DataIO<T> std = clockwerk::DataIO<T>(this, "std");
    protected:
        std::mt19937 _engine;
        std::normal_distribution<double> _distribution;
    };
 
    template <typename T>
    NormalRandom<T>::NormalRandom(T set_mean, T set_std, unsigned int seed)
        : _engine{seed}, _distribution(0, 1.0) {
        mean(set_mean);
        std(set_std);
    }
 
    template <typename T>
    T NormalRandom<T>::operator () () {
        // Calculate our distribution as 
        // val = mean + rng*seed
        // Where we 
 
        return mean() + _distribution(_engine)*std();
    }
 
}
 
#endif