Gaussian.h

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#pragma once

#include <boost/shared_ptr.hpp>
#include <iostream>
#include <iomanip>
#include <string>
#include <map>
#include <random>
#include <cmath>

namespace ASR
{
 
    class Gaussian
    {
    private:
      double mean;
      double var;
      
    public:
      
        Gaussian(double mean, double variance)
        {
          this->mean = mean;
          this->var = variance;
        }
        
        
        float sampleRandomValue()
        {
          std::random_device rd;
          std::mt19937 gen(rd()); 
          
          // values near the mean are the most likely
          // standard deviation affects the dispersion of generated values from the mean
          std::normal_distribution<> d(mean, var);
          
          return d(gen);
        }
        
        void sampleRandomValues(std::vector<float> &v, int n)
        {
      assert(n > 0);
      //assert(v != nullptr);
          
          std::random_device rd;
          std::mt19937 gen(rd()); 
          
          // values near the mean are the most likely
          // standard deviation affects the dispersion of generated values from the mean
          std::normal_distribution<> d(mean, var);
          
          for (int i = 0; i < n; i++)
          {
            v.push_back( d(gen) );
          }
        }
        
        
        
    private:
        void test()
        {
          std::random_device rd;
          std::mt19937 gen(rd()); 
          std::normal_distribution<> d(mean, var);
          
          std::map<int, int> hist;
          for(int n=0; n<10000; ++n) 
          {
            ++hist[std::round(d(gen))];
          }
          for(auto p : hist) 
          {
            std::cout << std::fixed << std::setprecision(1) << std::setw(2)
            << p.first << ' ' << std::string(p.second/200, '*') << '\n';  
          }
        }
        
        
    };
    
    typedef boost::shared_ptr<Gaussian> GaussianPtr;
  
  
  
}