Class RandomNumberGenerator

pyvrp/cpp/RandomNumberGenerator.h:25–82

* RandomNumberGenerator(seed: int) * * This class implements a XOR-shift pseudo-random number generator (RNG). It * generates the next number of a sequence by repeatedly taking the 'exclusive * or' (the ``^`` operator) of a number with a bit-shifted version of itself. * See `here `_ for more details. * * Parameters * ---------- * seed * Seed us

 *     Seed used to set the initial RNG state.
 */
class RandomNumberGenerator
{
    std::array<uint32_t, 4> state_;

public:
    typedef uint32_t result_type;

    explicit RandomNumberGenerator(uint32_t seed);
    explicit RandomNumberGenerator(std::array<uint32_t, 4> state);

    /**
     * @return The minimum value this pRNG can generate.
     */
    static constexpr size_t min();

    /**
     * @return The maximum value this pRNG can generate.
     */
    static constexpr size_t max();

    /**
     * Generates one pseudo-random integer in the range <code>[min(), max())
     * </code>.
     *
     * @return A pseudo-random integer.
     */
    result_type operator()();

    /**
     * Generates one pseudo-random double uniformly in the range [0, 1].
     *
     * @return A pseudo-random number in the range [0, 1].
     */
    double rand();

    /**
     * Generates one pseudo-random integer in the range <code>[0, high)</code>.
     *
     * @param high Upper bound on the integer to generate.
     * @return A pseudo-random integer.
     */
    template <typename T> result_type randint(T high);

    /**
     * Randomly shuffles the elements in the given range in-place using the
     * Fisher-Yates algorithm.
     *
     * @param first Iterator to the beginning of the range to shuffle.
     * @param last Iterator to the end of the range to shuffle.
     */
    template <typename RandomIt> void shuffle(RandomIt first, RandomIt last);

    /**
     * Returns the internal RNG state.
     */
    // Could be useful for debugging.
    std::array<uint32_t, 4> const &state() const;
};