/seed11

portable seeding for C++11 random generators and other extensions to C++11 <random> API

Primary LanguageC++MIT LicenseMIT

seed11 LicenseCI

Motivation

$ cat tests/motivation.cpp
#include <iostream>
#include <iterator>
#include <random>
#include <algorithm>
#include <functional>

int main()
{
	std::random_device rd;
	std::generate_n(
		std::ostream_iterator<unsigned>(std::cout, " "),
		4,
		std::ref(rd));
	std::cout << "\n";
}
$ x86_64-w64-mingw32-g++ -std=c++11 -Wall tests/motivation.cpp -o fail
$ for i in `seq 1 3`; do ./fail; done
3499211612 581869302 3890346734 3586334585
3499211612 581869302 3890346734 3586334585
3499211612 581869302 3890346734 3586334585

Well, that's just terrible... How could we make it better?

Synopsis

This library provides extensions to C++11 <random>:

  • seed11::seed_device - drop-in replacement for std::random_device, exists because of implementation bugs (I'm looking at you, MinGW)
  • seed11::make_seeded<RandomNumberEngine>() - create the engine seeded with thread local seed_device.
  • seed11::make_seeded<RandomNumberEngine>(URNG&& urng) - create the engine seeded with the uniform random number generator provided as an argument.
  • seed11::choice(RandomAccessIterator begin, RandomAccessIterator end) - returns an iterator to the random element (chosen using std::uniform_int_distribution and a thread local std::mt19937_64). If begin == end, end is returned.
  • seed11::choice(RandomAccessIterator begin, RandomAccessIterator end, URNG&& urng) - returns an iterator to the random element (chosen using std::uniform_int_distribution on a provided uniform random number generator). If begin == end, end is returned.

Building

cd build
cmake -G Ninja ..
ninja-build

You can as well choose any other generator, your choice...