imneme

// badseed:
//    Provides examples showing std::seed_seq is not a bijection
//    i.e., that some seeds get repeated for different inputs
//          and thus some other seeds must never be generated
 
#include <random>
#include <iostream>
#include <iomanip>
#include <cstddef>

imneme

/*
 * Random-Number Utilities (randutil)
 *     Addresses common issues with C++11 random number generation.
 *     Makes good seeding easier, and makes using RNGs easy while retaining
 *     all the power.
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2015-2022 Melissa E. O'Neill
 *

imneme

#ifndef XORSHIFT_HPP_INCLUDED
#define XORSHIFT_HPP_INCLUDED 1

/*
 * A C++ implementation of a family of truncated XorShift* generators.
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2017-19 Melissa E. O'Neill
 *

imneme

#ifndef XOROSHIRO_HPP_INCLUDED
#define XOROSHIRO_HPP_INCLUDED 1

/*
 * A C++ implementation of a family of Xoroshiro generators.
 *
 * See:
 *     https://en.wikipedia.org/wiki/Xoroshiro128%2B
 *     http://xoroshiro.di.unimi.it/xoroshiro128plus.c
 *

imneme

#ifndef JSF_HPP_INCLUDED
#define JSF_HPP_INCLUDED 1

/*
 * A C++ implementation of a Bob Jenkins Small Fast (Noncryptographic) PRNGs
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2018 Melissa E. O'Neill
 *

imneme

#ifndef GJRAND_HPP_INCLUDED
#define GJRAND_HPP_INCLUDED 1

/*
 * A C++ implementation of David Blackman's GJrand PRNG(s)
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2018 Melissa E. O'Neill
 *

imneme

#ifndef SFC_HPP_INCLUDED
#define SFC_HPP_INCLUDED 1

/*
 * A C++ implementation of Chris Doty-Humphrey's SFC PRNG(s)
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2018 Melissa E. O'Neill
 *

imneme

#ifndef LEHMER_HPP_INCLUDED
#define LEHMER_HPP_INCLUDED 1

/*
 * A C++ implementation of fast, 128-bit, Lehmer-style PRNGs
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2018 Melissa E. O'Neill
 *

imneme

#ifndef RND_ADAPTERS_HPP_INCLUDED
#define RND_ADAPTERS_HPP_INCLUDED 1

/*
 * A C++ implementation of a set of PRNG adapters.
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2018 Melissa E. O'Neill
 *

imneme

/*
 * Xoshiro256** Bad Repeats Demonstration
 *
 *     gcc -std=c99 -Wall -o xoshiro-bad-repeats xoshiro-bad-repeats.c
 *     ./xoshiro-bad-repeats | less
 *
 * In a PRNG the size of Xoshiro256**, we should expect about 10 "5-in-7"
 * repeats.  Xoshiro256** has more than 18 billion billion of them, which
 * is rather too many.  In fact, the number of bad repeats is larger than
 * the 2**64 range of the generator!