Random1.cpp

//
//  Random1.cpp
//
//
//  Created by carlos on 26/10/2018.
//
//

#include "Random1.hpp"
#include <cstdlib>
#include <cmath>

// the basic math functions should be in namespace
// std but aren't in VCPP6
#if !defined(_MSC_VER)
using namespace std;
#endif

double GetOneGaussianBySummation()
{
    double result = 0;
    
    for (unsigned long j=0; j < 12; j++)
        result += rand()/static_cast<double>(RAND_MAX);
    
    result -= 6.0;
    
    return result;
}

double GetOneGaussianByBoxMuller()
{
    double result;
    
    double x;
    double y;
    
    double sizeSquared;
    do
    {
        x = 2.0*rand()/static_cast<double>(RAND_MAX)-1;
        y = 2.0*rand()/static_cast<double>(RAND_MAX)-1;
        sizeSquared = x*x + y*y;
    }
    while
        ( sizeSquared >= 1.0);
    result = x*sqrt(-2*log(sizeSquared)/sizeSquared);
    
    return result;
}