randomGenerator.cpp

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#include "randomGenerator.h"

#include <chrono>
#include <cmath>
#include <ctime>
#include <iostream>

using namespace Utils;

RandomGenerator::RandomGenerator()
{
    gen.seed(time(NULL));
}

RandomGenerator::RandomGenerator(time_t seed)
{
    gen.seed(seed);
}

double RandomGenerator::drawUniform(double min, double max)
{
    double ret = unif(gen);
    ret *= (max-min);
    ret += min;
    return ret;
}

double RandomGenerator::drawExp(double lambda)
{
    if (lambda <= 0)
    {
        return 0;
    }
    double uni = unif(gen);
    return -log(uni)/lambda;
}


void RandomGenerator::seed(time_t seed)
{
    std::cout << "\033[1;32m" << "Using seed "<< seed << "\033[0m" << "\n"; //FIXME use the log class for color
    gen.seed(seed);
}


int RandomGenerator::drawUniformInt(int min, int max)
{
    double d;
    do
    {
        d = drawUniform((double) min, (double) max + 1.0);
    } while(d >= (double) max + 1.0);
    int ret = (int) floor(d);
    return ret;
}

std::vector<double> RandomGenerator::drawDistribution(int nbOfBins)
{
    std::vector<double> vector(nbOfBins);
    double total = 0.0;
    for (int i = 0; i < nbOfBins; i++)
    {
        vector[i] = drawUniform(0.0, 1.0);
        total += vector[i];
    }
    for (int i = 0; i < nbOfBins; i++)
    {
        vector[i] /= total;
    }
    return vector;
}

double RandomGenerator::drawBeta(double /*a*/, double /*b*/)
{
    /*TODO*/
    return 0.0;
}