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

/*
 * 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!

imneme

/*
 * Seeding Bias Test
 *
 *   - Runs through all possible seeds and examines the output for
 *     bias.  Doing so is only practical for 32-bit (or less) seeds
 *     and 32-bit (or less) output.
 *
 * Compilation note:
 *
 *   - You need to define the following preprocessor symbols to compile this

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

#ifndef ARC4_HPP_INCLUDED
#define ARC4_HPP_INCLUDED 1

/*
 * A C++ port of the OpenBSD Arc4 random number generator
 *
 * The MIT License (MIT)
 *
 * Copyright (C) 1996 David Mazieres <dm@lcs.mit.edu> for the OpenBSD project
 * C++ Port Copyright (c) 2014-18 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

/*
 * Show self-similarity issues with Vigna's xoshiro256**
 *
 * Originally posted in a NumPy developers discussion by Tyge Løvset
 * but simplified to only mix 32 outputs.
 *
 * Compile, and then test with PractRand by running
 *
 * ./xoshiro256-similarity \ 
 *   | ./RNG_test stdin64 -te 1 -tlmin 15 -tlmax 50 -tlmaxonly -multithreaded 

imneme

#ifndef XOSHIRO_HPP_INCLUDED
#define XOSHIRO_HPP_INCLUDED 1

/*
 * A C++ implementation of a family of Xoshiro generators.
 *
 * See:
 *     https://arxiv.org/abs/1805.01407
 *     http://xoshiro.di.unimi.it/xoshiro256plus.c
 *     http://xoshiro.di.unimi.it/xoshiro256starstar.c

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 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
 *