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Xoshiro-cpp

Xoshiro-cpp is a header-only pseudorandom number generator library for modern C++.
Based on David Blackman and Sebastiano Vigna's xoshiro/xoroshiro generators.

Features

  • Meets the std::uniform_random_bit_generator concept (C++20)
    • Works with std::uniform_int_distribution, std::shuffle and the other standard library functions
  • Mostly constexpr in C++17
  • Serialize / deserialize
  • Utility function double DoubleFromBits(uint64 v);
    • Converts given uint64 value v into a 64-bit floating point value in the range of [0.0, 1.0)
PRNG Output bits Period Footprint
SplitMix64 64 bits 2^64 8 bytes
xoshiro256+ 64 bits 2^256-1 32 bytes
xoshiro256++ 64 bits 2^256-1 32 bytes
xoshiro256** 64 bits 2^256-1 32 bytes
xoroshiro128+ 64 bits 2^128-1 16 bytes
xoroshiro128++ 64 bits 2^128-1 16 bytes
xoroshiro128** 64 bits 2^128-1 16 bytes
xoshiro128+ 32 bits 2^128-1 16 bytes
xoshiro128++ 32 bits 2^128-1 16 bytes
xoshiro128** 32 bits 2^128-1 16 bytes

Examples

# include <iostream>
# include "XoshiroCpp.hpp"

int main()
{
    using namespace XoshiroCpp;

    const std::uint64_t seed = 12345;

    Xoshiro256PlusPlus rng(seed);

    for (int i = 0; i < 5; ++i)
    {
        std::cout << rng() << '\n';
    }
}
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# include <iostream>
# include <random>
# include "XoshiroCpp.hpp"

int main()
{
    using namespace XoshiroCpp;

    const std::uint64_t seed = 12345;

    Xoshiro256PlusPlus rng(seed);

    std::uniform_int_distribution<int> dist(1, 6);

    for (int i = 0; i < 5; ++i)
    {
        std::cout << dist(rng) << '\n';
    }
}
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# include <algorithm>
# include <iostream>
# include "XoshiroCpp.hpp"

int main()
{
    using namespace XoshiroCpp;

    const std::uint64_t seed = 12345;

    Xoshiro256PlusPlus rng(seed);

    std::array<int, 10> ar = { 0,1,2,3,4,5,6,7,8,9 };

    std::shuffle(ar.begin(), ar.end(), rng);

    for (const auto& x : ar)
    {
        std::cout << x << '\n';
    }
}
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# include <iostream>
# include "XoshiroCpp.hpp"

int main()
{
    using namespace XoshiroCpp;

    const std::uint64_t seed = 12345;

    Xoshiro256PlusPlus rng(seed);

    for (int i = 0; i < 5; ++i)
    {
        std::cout << DoubleFromBits(rng()) << '\n';
    }
}
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0.265614

# include <iostream>
# include "XoshiroCpp.hpp"

int main()
{
    using namespace XoshiroCpp;

    // This example seed sequence { 111, 222, 333, 444 } is poorly
    // distributed (has a lot of '0' bits) and it is not suitable
    // for directly use in the generator's internal state.
    // SplitMix64 PRNG can be used to increase entropy.
    const Xoshiro256Plus::state_type initialStateA =
    {
        SplitMix64{ 111 }(),
        SplitMix64{ 222 }(),
        SplitMix64{ 333 }(),
        SplitMix64{ 444 }(),
    };

    Xoshiro256PlusPlus rngA(initialStateA);

    for (int i = 0; i < 3; ++i)
    {
        std::cout << rngA() << '\n';
    }

    const Xoshiro256Plus::state_type state = rngA.serialize();

    Xoshiro256PlusPlus rngB(state);

    for (int i = 0; i < 3; ++i)
    {
        std::cout << std::boolalpha << (rngA() == rngB()) << '\n';
    }

    rngB.deserialize(initialStateA);

    for (int i = 0; i < 3; ++i)
    {
        std::cout << rngB() << '\n';
    }
}
9228892280983206813
11892737616047535485
12786908792686548306
true
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true
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12786908792686548306

Roadmap

  • SplitMix64
  • xoshiro256+
  • xoshiro256++
  • xoshiro256**
  • xoroshiro128+
  • xoroshiro128++
  • xoroshiro128**
  • xoshiro128+
  • xoshiro128++
  • xoshiro128**
  • xoroshiro64*
  • xoroshiro64**

License

Xoshiro-cpp is distributed under the MIT license.