library/random.hpp File Reference

Classes
struct	splitmix64
	Pseudo-RNG generator. More...

Namespaces
	cxxomfort
	Namespace of the cxxomfort library.
	cxxomfort::library
	Supplements to backports and other utilities.

Typedefs
typedef std::linear_congruential_engine< uint32_t, 1664525, 1013904223, 0 >	lcg_numerical_recipes_rand
	LCG as it appears in Numerical Recipes. More...
typedef std::linear_congruential_engine< uint64_t, 6364136223846793005, 1, 0 >	musl_rand
	LCG specification as it appears in MUSL Libc.This is an alternative to eg.: std::minstd and other linear congruential engines. More...
typedef std::linear_congruential_engine< uint_least64_t, 0x00000005deece66dULL, 0xb, 0x0001000000000000ULL >	rand48
	LCG specification as it appears in FreeBSD.This is an alternative to eg.: std::minstd and other linear congruential engines. More...
typedef std::linear_congruential_engine< unsigned int, 0, 4, 0 >	xkcd221_rand
	LCG specification following Randall Munroe's xkcd #221. More...

Functions
template<typename Gen , typename Integer >
Integer	uniform_choose (Gen &g, Integer a, Integer b)
	Given a generator g , generate and choose an integer in the range [a, b]. More...
template<typename Gen , typename Iterator >
Iterator	uniform_pick (Gen &g, Iterator ini, Iterator fin)
	Choose one in a sequence of values [ini,fin). More...

Detailed Description

<random>:

Typedef Documentation

lcg_numerical_recipes_rand

lcg_numerical_recipes_rand

LCG as it appears in Numerical Recipes.

See also

https://en.wikipedia.org/wiki/Numerical_Recipes

This is an alternative to eg.: std::minstd and other linear congruential engines, using as parameters to the generator the parameters specified in Numerical Recipes .

When invoked with operator() returns a uint32_t value.

musl_rand

musl_rand

LCG specification as it appears in MUSL Libc.This is an alternative to eg.: std::minstd and other linear congruential engines.

When invoked with operator() returns a uint64_t value.

rand48

rand48

LCG specification as it appears in FreeBSD.This is an alternative to eg.: std::minstd and other linear congruential engines.

When invoked with operator() returns a uint64_t value within a range that uses the first (lowest) 48 bits.

xkcd221_rand

xkcd221_rand

LCG specification following Randall Munroe's xkcd #221.

See also

https://xkcd.com/221/

This is an alternative to eg.: std::minstd and other linear congruential engines.

When invoked with operator() returns a unsigned value. The generator is equivalent to the following hand-written code:

struct xkcd221_r {
 constexpr unsigned int () const noexcept { 
     return 4; // chosen by fair dice roll, guaranteed to be random
 } 
};

Function Documentation

uniform_choose()

Integer cxxomfort::library::random::uniform_choose	(	Gen &	g,
		Integer	a,
		Integer	b
	)

Given a generator g , generate and choose an integer in the range [a, b].

Parameters

g	A generator object (lvalue).

Returns

An Integer value.

Precondition

Integer is a C++ integer type.

Referenced by cxxomfort::library::random::uniform_choose().

uniform_pick()

Iterator cxxomfort::library::random::uniform_pick	(	Gen &	g,
		Iterator	ini,
		Iterator	fin
	)

Choose one in a sequence of values [ini,fin).

Parameters

ini,fin

A sequence's begin and end iterators.

Returns

An iterator in the range [ini,fin).

This function uses uniform_choose() on the passed generator g to uniformly pick one iterator within the desired range.

Referenced by cxxomfort::library::random::uniform_pick().