RNG

A simple C++ random number generator. It uses the latest and fastest Sebastiano Vigna's algorithm: xoroshiro128+.

It produces 64-bit integers. In my simple test it is more than five times faster than the mt19937_64 generator from the C++ standard library:

1000000000 rng128 calls
    0.2919 sec
1000000000 mt19937_64 calls
    1.59899 sec

As for the quality of the generator please refer to the results on Sebastiano Vigna's page.

In addition to the RNG itself there are two utility classes that produce 64-bit seeds for initializing the RNG. One extracts entropy from the system scheduler measuring it with x86 rdtsc instruction. The other uses std::random_device from the standard C++ library.

Sample code:

rng::tsc_seed seed;
rng::rng128 gen(seed());
std::cout << "a random number: " << gen() << "\n";

On Linux random_device_seed is faster than tsc_seed. But on macOS it is other way round.