random number generator speed benchmark for https://cppbenchmarks.wordpress.com/2020/10/11/speed-comparison-of-random-number-generators/

random_generators_speed.cpp

#include <iostream>
#include <random>
#include <chrono>
#include <iomanip>

template <typename RandomEngineType> void benchmark_random_generator(const std::string &name) {
  RandomEngineType generator;

  std::uniform_int_distribution<> distribution(0, 1000);

  constexpr int nIterations = 300000000;

  const auto start = std::chrono::steady_clock::now();

  for (int i = 0; i < nIterations; ++i) {
    distribution(generator);
  }

  const auto end = std::chrono::steady_clock::now();

  std::cout << name << " " << std::setprecision(3)
            << std::chrono::duration_cast<std::chrono::nanoseconds>(end - start).count() / static_cast<double>(nIterations)
            << " ns per random number\n";
};

int main() {

  benchmark_random_generator<std::minstd_rand>("minstd_rand");
  benchmark_random_generator<std::minstd_rand0>("minstd_rand0");
  benchmark_random_generator<std::mt19937>("mt19937");
  benchmark_random_generator<std::mt19937_64>("mt19937_64");
  benchmark_random_generator<std::ranlux24_base>("ranlux24_base");
  benchmark_random_generator<std::ranlux48_base>("ranlux48_base");
  benchmark_random_generator<std::ranlux24>("ranlux24");
  benchmark_random_generator<std::ranlux48>("ranlux48");
  benchmark_random_generator<std::knuth_b>("knuth_b");

  return EXIT_SUCCESS;
}