orb5x::RandomGenerator Class Reference

Deterministic ORB5 pseudo-random stream and seed jump operations. More...

#include "random_generator.hpp"

Static Public Member Functions
static void	decimal_to_seed (const std::string &decimal, std::array< int, SEED_SIZE > &seed)
	Convert decimal digits to the eight-digit base-2^14 seed.
static void	next_seed (int n0, std::array< int, SEED_SIZE > &seed)
	Jump a seed along the primary independent stream family.
static void	next_seed3 (int n0, int n1, int n2, std::array< int, SEED_SIZE > &seed)
	Apply signed jumps in three hierarchical stream dimensions.
static void	random_array (std::vector< Real > &y, int n, int &p, std::vector< Real > &r)
	Draw an array of dimensionless uniform variates.
static void	random_gauss (std::vector< Real > &y, int n, int &p, std::vector< Real > &r)
	Draw standard-normal variates using the Box–Muller transform.
static void	random_init (const std::array< int, SEED_SIZE > &seed, int &p, std::vector< Real > &r)
	Initialize a pseudo-random stream from a deterministic seed.
static void	random_orb (int &p, std::vector< Real > &r, Real &random2)
	Draw one dimensionless uniform variate from the stream.
static void	seed_to_decimal (const std::array< int, SEED_SIZE > &seed, std::string &decimal)
	Format a base-2^14 seed as a fixed-width decimal field.

Static Public Attributes
static constexpr int	B = 16384
	Seed radix, 2^14.
static constexpr Real	DEL = 1.0 / (1ULL << 14)
	Reciprocal seed radix, 2^-14.
static constexpr Real	MULT = 1.0 * (1ULL << 23)
	Legacy single-precision scale, 2^23.
static constexpr int	RAN_K = 100
	Values retained in a stream batch.
static constexpr int	SEED_SIZE = 8
	Base-2^14 digits in a seed.
static constexpr Real	ULP = 1.0 / (1ULL << 47)
	Stream perturbation, 2^-47.
static constexpr Real	ULP2 = 1.0 / (1ULL << 48)
	Uniform half-ULP offset, 2^-48.

Detailed Description

Deterministic ORB5 pseudo-random stream and seed jump operations.

This class preserves the original base-2^14 seed representation and lagged-Fibonacci stream so marker loading and stochastic operators can reproduce reference sequences. A stream consists of a 100-value state vector r and cursor p; callers must pass both back on every draw. Output uniforms are dimensionless and shifted away from exact zero, and Gaussian output is standard normal (zero mean, unit variance).

Member Function Documentation

decimal_to_seed()

static void orb5x::RandomGenerator::decimal_to_seed ( const std::string &  decimal, std::array< int, SEED_SIZE > &  seed  )

static

Convert decimal digits to the eight-digit base-2^14 seed.

Parameters

[in]	decimal	Text whose non-decimal characters are ignored.
[out]	seed	Converted seed, least-significant radix digit first.

next_seed()

static void orb5x::RandomGenerator::next_seed ( int  n0, std::array< int, SEED_SIZE > &  seed  )

static

Jump a seed along the primary independent stream family.

Parameters

[in]	n0	Signed jump count; positive advances and negative reverses.
[in,out]	seed	Seed transformed in place; unchanged when n0 == 0.

next_seed3()

static void orb5x::RandomGenerator::next_seed3 ( int  n0, int  n1, int  n2, std::array< int, SEED_SIZE > &  seed  )

static

Apply signed jumps in three hierarchical stream dimensions.

Parameters

[in]	n0	Primary-dimension jump count.
[in]	n1	Secondary-dimension jump count.
[in]	n2	Tertiary-dimension jump count.
[in,out]	seed	Seed transformed in order n2, n1, then n0.

random_array()

static void orb5x::RandomGenerator::random_array ( std::vector< Real > &  y, int  n, int &  p, std::vector< Real > &  r  )

static

Draw an array of dimensionless uniform variates.

Parameters

[out]	y	Resized to n and filled in stream order.
[in]	n	Number of requested values; non-positive requests do nothing.
[in,out]	p	Stream cursor.
[in,out]	r	Stream state.

random_gauss()

static void orb5x::RandomGenerator::random_gauss ( std::vector< Real > &  y, int  n, int &  p, std::vector< Real > &  r  )

static

Draw standard-normal variates using the Box–Muller transform.

Parameters

[out]	y	Resized to n; values are dimensionless with mean zero and variance one in distribution.
[in]	n	Number of requested values; non-positive requests do nothing.
[in,out]	p	Stream cursor.
[in,out]	r	Stream state.

random_init()

static void orb5x::RandomGenerator::random_init ( const std::array< int, SEED_SIZE > &  seed, int &  p, std::vector< Real > &  r  )

static

Initialize a pseudo-random stream from a deterministic seed.

Parameters

[in]	seed	Eight base-2^14 seed digits.
[out]	p	Cursor set to RAN_K, causing the first draw to refresh the batch.
[out]	r	Stream state resized to RAN_K dimensionless values.

random_orb()

static void orb5x::RandomGenerator::random_orb ( int &  p, std::vector< Real > &  r, Real &  random2  )

static

Draw one dimensionless uniform variate from the stream.

Parameters

[in,out]	p	Current batch cursor, advanced by one.
[in,out]	r	State vector initialized by random_init().
[out]	random2	Uniform variate shifted by 2^-48, nominally in (0,1).

seed_to_decimal()

static void orb5x::RandomGenerator::seed_to_decimal ( const std::array< int, SEED_SIZE > &  seed, std::string &  decimal  )

static

Format a base-2^14 seed as a fixed-width decimal field.

Parameters

[in]	seed	Seed digits, each expected in [0,B).
[in,out]	decimal	Its incoming length selects output field width; the content is replaced by right-aligned decimal text.

Member Data Documentation

B

constexpr int orb5x::RandomGenerator::B = 16384

staticconstexpr

Seed radix, 2^14.

DEL

constexpr Real orb5x::RandomGenerator::DEL = 1.0 / (1ULL << 14)

staticconstexpr

Reciprocal seed radix, 2^-14.

MULT

constexpr Real orb5x::RandomGenerator::MULT = 1.0 * (1ULL << 23)

staticconstexpr

Legacy single-precision scale, 2^23.

RAN_K

constexpr int orb5x::RandomGenerator::RAN_K = 100

staticconstexpr

Values retained in a stream batch.

SEED_SIZE

constexpr int orb5x::RandomGenerator::SEED_SIZE = 8

staticconstexpr

Base-2^14 digits in a seed.

ULP

constexpr Real orb5x::RandomGenerator::ULP = 1.0 / (1ULL << 47)

staticconstexpr

Stream perturbation, 2^-47.

ULP2

constexpr Real orb5x::RandomGenerator::ULP2 = 1.0 / (1ULL << 48)

staticconstexpr

Uniform half-ULP offset, 2^-48.

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The documentation for this class was generated from the following file:

• random_generator.hpp