Random number generator benchmarks

rand.cc

#include <cstdlib>
#include <iostream>
#include <chrono>
#include <random>

#include<gsl/gsl_rng.h>

class Timer
{
    private:
        std::chrono::high_resolution_clock::time_point start_time;
        std::chrono::high_resolution_clock::time_point stop_time;

    public:
        void start()
        {
            start_time = std::chrono::high_resolution_clock::now();
        }

        void stop()
        {
            stop_time = std::chrono::high_resolution_clock::now();
        }

        double measure()
        {
            using namespace std::chrono;
            return duration_cast<nanoseconds>
                (stop_time - start_time).count() / 1.0;
        }
};

template<typename T>
class Random
{
    private:
        T generator;

    public:
        Random()
            : generator
              (std::chrono::high_resolution_clock::now().time_since_epoch().count())
    {
    }

        int generate_integer(int begin, int end)
        {
            return std::uniform_int_distribution<int>(begin, end - 1)(generator);
        }
};

int main()
{
    constexpr int n = 300000000;
    Random<std::minstd_rand> mr;
    Random<std::mt19937> mt;
    Random<std::mt19937_64> mt64;
    gsl_rng * gslmt = gsl_rng_alloc (gsl_rng_mt19937);
    Timer t;
    for (int j = 0; j < 3; ++j)
    {
        t.start();
        for (int i = 0; i < n; ++i)
        {
            /* static_cast<volatile void> */(std::rand() % 10);
        }
        t.stop();
        std::cout << "rand           " << t.measure() /n << " ns per rand" << std::endl;

        t.start();
        for (int i = 0; i < n; ++i)
        {
            /* static_cast<volatile void> */(mr.generate_integer(0, 10));
        }
        t.stop();
        std::cout << "minstd         " << t.measure() /n << " ns per rand" << std::endl;

        t.start();
        for (int i = 0; i < n; ++i)
        {
            /* static_cast<volatile void> */(mt.generate_integer(0, 10));
        }
        t.stop();
        std::cout << "mersenne       " << t.measure() /n << " ns per rand" << std::endl;

        t.start();
        for (int i = 0; i < n; ++i)
        {
            /* static_cast<volatile void> */(mt64.generate_integer(0, 10));
        }
        t.stop();
        std::cout << "mersenne 64    " << t.measure() /n << " ns per rand" << std::endl;

        t.start();
        for (int i = 0; i < n; ++i)
        {
            /* static_cast<volatile void> */(gsl_rng_get(gslmt));
        }
        t.stop();
        std::cout << "gsl mersenne   " << t.measure() /n << " ns per rand" << std::endl;
    }
    gsl_rng_free(gslmt);
}

results

pcm@PCMC01W01:~                                                                                                                
▶ ./rand
rand           16.3945 ns per rand
minstd         20.1129 ns per rand
mersenne       18.9779 ns per rand
mersenne 64    4.77588 ns per rand
gsl mersenne   6.10239 ns per rand
rand           16.1322 ns per rand
minstd         20.1151 ns per rand
mersenne       18.9815 ns per rand
mersenne 64    4.77733 ns per rand
gsl mersenne   6.10307 ns per rand
rand           16.1384 ns per rand
minstd         20.1181 ns per rand
mersenne       18.9783 ns per rand
mersenne 64    4.77653 ns per rand
gsl mersenne   6.10385 ns per rand

pcm@PCMC01W01:~                                                                                                                
▶ gcc --version
gcc (Ubuntu 4.8.4-2ubuntu1~14.04) 4.8.4
Copyright (C) 2013 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

▶ ./rand                                         
rand           19.3163 ns per rand
minstd         21.7224 ns per rand
mersenne       25.5529 ns per rand
mersenne 64    5.55641 ns per rand
gsl mersenne   7.55933 ns per rand
rand           18.3189 ns per rand
minstd         21.7219 ns per rand
mersenne       25.5505 ns per rand
mersenne 64    5.55641 ns per rand
gsl mersenne   7.56132 ns per rand
rand           18.3168 ns per rand
minstd         21.7207 ns per rand
mersenne       25.55 ns per rand
mersenne 64    5.55821 ns per rand
gsl mersenne   7.5594 ns per rand

pcm@PCMWS1:~                                                                                                                   
▶ gcc --version
gcc (Ubuntu 4.8.4-2ubuntu1~14.04) 4.8.4
Copyright (C) 2013 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.