Class for encapsulating random number generation. This class is MPI and OpenMP safe. More...

#include <CD_Random.H>

Public Member Functions
	Random ()=delete
	Disallowed constructor.

	Random (const Random &a_other)=delete
	Deleted copy constructor. Must be impossible because this is a singleton.

	Random (const Random &&a_other)=delete
	Deleted copy constructor. Must be impossible because this is a singleton.

Random &	operator= (const Random &a_other)=delete
	Disallowed copy assignment.

Random &	operator= (const Random &&a_other)=delete
	Disallowed move assignment.

Static Public Member Functions
template<typename T , typename = std::enable_if_t<std::is_integral<T>::value>>
static T	getPoisson (const Real a_mean)
	Get Poisson distributed number.

template<typename T , typename = std::enable_if_t<std::is_integral<T>::value>>
static T	getBinomial (const T a_N, const Real a_p) noexcept
	Get Poisson distributed number.

static Real	getUniformReal01 ()
	Get a uniform real number on the interval [0,1].

static Real	getUniformReal11 ()
	Get a uniform real number on the interval [-1,1].

static Real	getNormal01 ()
	Get a number from a normal distribution centered on zero and variance 1.

static RealVect	getDirection ()
	Get a random direction in space.

template<typename T >
static Real	get (T &a_distribution)
	For getting a random number from a user-supplied distribution. T must be a distribution for which we can call T(s_rng)

template<typename T >
static size_t	getDiscrete (T &a_distribution)
	For getting a random number from a user-supplied distribution. T must be a distribution for which we can call T(s_rng)

static void	seed ()
	Seed the RNG.

static void	setSeed (const int a_seed)
	Set the RNG seed.

static void	setRandomSeed ()
	Set a random RNG seed.

static RealVect	randomPosition (const RealVect a_lo, const RealVect a_hi) noexcept
	Return a random position in the cube (a_lo, a_hi);.

static RealVect	randomPosition (const RealVect a_cellPos, const RealVect a_lo, const RealVect a_hi, const RealVect a_bndryCentroid, const RealVect a_normal, const Real a_dx, const Real a_kappa) noexcept
	Draw a random position physical somewhere in a grid cell.

static RealVect	randomPosition (const RealVect a_lo, const RealVect a_hi, const RealVect a_bndryCentroid, const RealVect a_normal) noexcept
	Draw a random position somewhere in a cut-cell.

Detailed Description

Class for encapsulating random number generation. This class is MPI and OpenMP safe.

The user can specify a seed 's' where each MPI rank will initialize their RNG with seed 's + procID()'. Note that unless the user specifies Random.seed = <number> in the input script, the RNG will use a seed of '0 + procID()' for the various ranks. If the user specifies a <number> less than 0, a random seed will be used.

Constructor & Destructor Documentation

◆ Random() [1/2]

Random::Random ( const Random & a_other )

delete

Deleted copy constructor. Must be impossible because this is a singleton.

Parameters

[in] a_other Other RNG engine.

◆ Random() [2/2]

Random::Random ( const Random && a_other )

delete

Deleted copy constructor. Must be impossible because this is a singleton.

Parameters

[in] a_other Other RNG engine.

Member Function Documentation

◆ get()

template<typename T >

Real Random::get ( T & a_distribution )

inlinestatic

For getting a random number from a user-supplied distribution. T must be a distribution for which we can call T(s_rng)

Parameters

[in] a_distribution Distribution. Must have object of type

◆ getBinomial()

template<typename T , typename >

T Random::getBinomial	(	const T	a_N,
		const Real	a_p
	)

inlinestaticnoexcept

Get Poisson distributed number.

Parameters

[in]	a_N	Number of trials
[in]	a_p	The usual success probability in binomial distributions

◆ getDirection()

RealVect Random::getDirection ( )

inlinestatic

Get a random direction in space.

Uses Marsaglia algorithm.

◆ getDiscrete()

template<typename T >

size_t Random::getDiscrete ( T & a_distribution )

inlinestatic

For getting a random number from a user-supplied distribution. T must be a distribution for which we can call T(s_rng)

Parameters

[in] a_distribution Distribution. Must have object of type

◆ getPoisson()

template<typename T , typename >

T Random::getPoisson ( const Real a_mean )

inlinestatic

Get Poisson distributed number.

Parameters

[in] a_mean Poisson mean value (inverse rate)

◆ operator=() [1/2]

Random & Random::operator= ( const Random && a_other )

delete

Disallowed move assignment.

Parameters

[in] a_other Other RNG engine.

◆ operator=() [2/2]

Random & Random::operator= ( const Random & a_other )

delete

Disallowed copy assignment.

Parameters

[in] a_other Other RNG engine.

◆ randomPosition() [1/3]

RealVect Random::randomPosition	(	const RealVect	a_cellPos,
		const RealVect	a_lo,
		const RealVect	a_hi,
		const RealVect	a_bndryCentroid,
		const RealVect	a_normal,
		const Real	a_dx,
		const Real	a_kappa
	)

inlinestaticnoexcept

Draw a random position physical somewhere in a grid cell.

This is the version that respects cut-cells – it will draw a position (through rejection sampling) such that the particle ends up on the correct side of the EB.

Parameters

[in]	a_cellPos	Cell-center position.
[in]	a_lo	Lower-left corner of volume that encloses the cut-cell. This is relative to the unit cell.
[in]	a_hi	Upper-right corner of volume that encloses the cut-cell. This is relative to the unit cell.
[in]	a_bndryCentroid	EB centroid position
[in]	a_normal	EB normal (points into the fluid region)
[in]	a_dx	Grid resolution
[in]	a_kappa	Cell volume

◆ randomPosition() [2/3]

RealVect Random::randomPosition	(	const RealVect	a_lo,
		const RealVect	a_hi
	)

inlinestaticnoexcept

Return a random position in the cube (a_lo, a_hi);.

Parameters

[in]	a_lo	Lower-left corner
[in]	a_hi	Upper-right corner

◆ randomPosition() [3/3]

RealVect Random::randomPosition	(	const RealVect	a_lo,
		const RealVect	a_hi,
		const RealVect	a_bndryCentroid,
		const RealVect	a_normal
	)

inlinestaticnoexcept

Draw a random position somewhere in a cut-cell.

Parameters

[in]	a_lo	Lower-left corner of volume that encloses the cut-cell. This is relative to the unit cell.
[in]	a_hi	Upper-right corner of volume that encloses the cut-cell. This is relative to the unit cell.
[in]	a_bndryCentroid	EB centroid position
[in]	a_normal	EB normal (points into the fluid region)

Returns: Returns a position inside the cut-cell and on the correct side of the EB.

◆ setSeed()

void Random::setSeed ( const int a_seed )

inlinestatic

Set the RNG seed.

If using MPI, the seed is set to a_seed + procID().

Parameters

[in] a_seed Seed to use for RNG.

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

Source/Utilities/CD_Random.H
Source/Utilities/CD_Random.cpp
Source/Utilities/CD_RandomImplem.H

Public Member Functions

Static Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ Random() [1/2]

◆ Random() [2/2]

Member Function Documentation

◆ get()

◆ getBinomial()

◆ getDirection()

◆ getDiscrete()

◆ getPoisson()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ randomPosition() [1/3]

◆ randomPosition() [2/3]

◆ randomPosition() [3/3]

◆ setSeed()