Utilities

General purpose utilities. More...

Classes
class	amrex::ParmParse
	Parse Parameters From Command Line and Input Files. More...
class	amrex::IParser
class	amrex::Parser

Functions
Real	amrex::Random ()
	Generate a psuedo-random double from uniform distribution.
__host__ __device__ Real	amrex::Random (RandomEngine const &random_engine)
Real	amrex::RandomNormal (Real mean, Real stddev)
	Generate a psuedo-random double from a normal distribution.
__host__ __device__ Real	amrex::RandomNormal (Real mean, Real stddev, RandomEngine const &random_engine)
unsigned int	amrex::RandomPoisson (Real lambda)
	Generate a psuedo-random integer from a Poisson distribution.
__host__ __device__ unsigned int	amrex::RandomPoisson (Real lambda, RandomEngine const &random_engine)
Real	amrex::RandomGamma (Real alpha, Real beta)
	Generate a psuedo-random floating point number from the Gamma distribution.
__host__ __device__ Real	amrex::RandomGamma (Real alpha, Real beta, RandomEngine const &random_engine)
unsigned int	amrex::Random_int (unsigned int n)
	Generates one pseudorandom unsigned integer which is uniformly distributed on [0,n-1]-interval for each call.
__host__ __device__ unsigned int	amrex::Random_int (unsigned int n, RandomEngine const &random_engine)
ULong	amrex::Random_long (ULong n)
	Generates one pseudorandom unsigned long which is uniformly distributed on [0,n-1]-interval for each call.
void	amrex::FillRandom (Real *p, Long N)
void	amrex::FillRandomNormal (Real *p, Long N, Real mean, Real stddev)
void	amrex::InitRandom (ULong cpu_seed, int nprocs=ParallelDescriptor::NProcs(), ULong gpu_seed=detail::DefaultGpuSeed())
	Set the seed of the random number generator.
void	amrex::ResetRandomSeed (ULong cpu_seed, ULong gpu_seed=detail::DefaultGpuSeed())
void	amrex::SaveRandomState (std::ostream &os)
	Save and restore random state.
void	amrex::RestoreRandomState (std::istream &is, int nthreads_old, int nstep_old)
void	amrex::UniqueRandomSubset (Vector< int > &uSet, int setSize, int poolSize, bool printSet=false)
	Create a unique subset of random numbers from a pool of integers in the range [0, poolSize - 1] the set will be in the order they are found setSize must be <= poolSize uSet will be resized to setSize if you want all processors to have the same set, call this on one processor and broadcast the array.

Detailed Description

General purpose utilities.

This topic covers general purpose utilities used throughout AMReX and AMReX applications.

Central capabilities include:

• amrex::ParmParse
• amrex::Parser
• amrex::IParser
• AMREX_ENUM
• amrex::Random
• amrex::Random_int
• amrex::Random_long
• amrex::RandomNormal
• amrex::RandomPoisson
• amrex::RandomGamma
• amrex::FillRandom
• amrex::FillRandomNormal
• amrex::InitRandom
• amrex::ResetRandomSeed

Function Documentation

FillRandom()

void amrex::FillRandom	(	Real *	p,
		Long	N
	)

Fill random numbers from uniform distribution. The range is [0,1) for CPU and SYCl, and (0,1] for CUADA and HIP.

FillRandomNormal()

void amrex::FillRandomNormal	(	Real *	p,
		Long	N,
		Real	mean,
		Real	stddev
	)

Fill random numbers from normal distribution

InitRandom()

void amrex::InitRandom	(	ULong	cpu_seed,
		int	nprocs = ParallelDescriptor::NProcs(),
		ULong	gpu_seed = detail::DefaultGpuSeed()
	)

Set the seed of the random number generator.

There is also an entry point for Fortran callable as:

INTEGER seed call blutilinitrand(seed)

or

INTEGER seed call blinitrand(seed)

Random() [1/2]

Real amrex::Random

(

)

Generate a psuedo-random double from uniform distribution.

Generates one pseudorandom real number (double) from a uniform distribution between 0.0 and 1.0 (0.0 included, 1.0 excluded)

Random() [2/2]

__host__ __device__ Real amrex::Random ( RandomEngine const &  random_engine )

inline

Random_int() [1/2]

unsigned int amrex::Random_int

(

unsigned int

n

)

Generates one pseudorandom unsigned integer which is uniformly distributed on [0,n-1]-interval for each call.

The CPU version of this function uses C++11's mt19937. The GPU version uses CURAND's XORWOW generator.

Random_int() [2/2]

__host__ __device__ unsigned int amrex::Random_int ( unsigned int  n, RandomEngine const &  random_engine  )

inline

Random_long()

ULong amrex::Random_long

(

ULong

n

)

Generates one pseudorandom unsigned long which is uniformly distributed on [0,n-1]-interval for each call.

The CPU version of this function uses C++11's mt19937. There is no GPU version.

RandomGamma() [1/2]

Real amrex::RandomGamma	(	Real	alpha,
		Real	beta
	)

Generate a psuedo-random floating point number from the Gamma distribution.

Generates one real number (single or double) extracted from a Gamma distribution, given the Real parameters alpha and beta. alpha and beta must both be > 0. The CPU version of this function relies on the Standard Template Library The GPU version of this function relies is implemented in terms of Random and RandomNormal.

RandomGamma() [2/2]

__host__ __device__ Real amrex::RandomGamma ( Real  alpha, Real  beta, RandomEngine const &  random_engine  )

inline

RandomNormal() [1/2]

Real amrex::RandomNormal	(	Real	mean,
		Real	stddev
	)

Generate a psuedo-random double from a normal distribution.

Generates one pseudorandom real number (double) from a normal distribution with mean 'mean' and standard deviation 'stddev'.

RandomNormal() [2/2]

__host__ __device__ Real amrex::RandomNormal ( Real  mean, Real  stddev, RandomEngine const &  random_engine  )

inline

RandomPoisson() [1/2]

unsigned int amrex::RandomPoisson

(

Real

lambda

)

Generate a psuedo-random integer from a Poisson distribution.

Generates one pseudorandom positive integer number (double) extracted from a Poisson distribution, given the Real parameter lambda. The CPU version of this function relies on the standard Template Library The GPU version of this function relies on the cuRAND library

RandomPoisson() [2/2]

__host__ __device__ unsigned int amrex::RandomPoisson ( Real  lambda, RandomEngine const &  random_engine  )

inline

ResetRandomSeed()

void amrex::ResetRandomSeed	(	ULong	cpu_seed,
		ULong	gpu_seed
	)

RestoreRandomState()

void amrex::RestoreRandomState	(	std::istream &	is,
		int	nthreads_old,
		int	nstep_old
	)

SaveRandomState()

void amrex::SaveRandomState

(

std::ostream &

os

)

Save and restore random state.

UniqueRandomSubset()

void amrex::UniqueRandomSubset	(	Vector< int > &	uSet,
		int	setSize,
		int	poolSize,
		bool	printSet
	)

Create a unique subset of random numbers from a pool of integers in the range [0, poolSize - 1] the set will be in the order they are found setSize must be <= poolSize uSet will be resized to setSize if you want all processors to have the same set, call this on one processor and broadcast the array.