OpenANN::RandomNumberGenerator Class Reference

A utility class that simplifies the generation of random numbers. More...

#include <Random.h>

Public Member Functions
	RandomNumberGenerator ()
	Initialize the seed. More...
void	seed (unsigned int seed)
	Set the seed to ensure repeatability. More...
int	generateInt (int min, int range) const
	Draw an integer from a uniform distribution. More...
size_t	generateIndex (size_t size) const
	Draw an index from a uniform distribution. More...
template<class T >
T	generate (T min, T range) const
	Draw a number from a uniform distribution. More...
template<class T >
T	sampleNormalDistribution () const
	Draw a sample from a normal distribution with zero mean and variance 1. More...
template<class C >
void	generateIndices (int n, C &result, bool initialized=false)
	Generate a random sequence of indices. More...
template<class M >
void	fillNormalDistribution (M &matrix, double stdDev=1.0)

Detailed Description

A utility class that simplifies the generation of random numbers.

Constructor & Destructor Documentation

OpenANN::RandomNumberGenerator::RandomNumberGenerator

(

)

Initialize the seed.

Member Function Documentation

template<class M >

void OpenANN::RandomNumberGenerator::fillNormalDistribution ( M &  matrix, double  stdDev = 1.0  )

inline

template<class T >

T OpenANN::RandomNumberGenerator::generate ( T  min, T  range  ) const

inline

Draw a number from a uniform distribution.

Template Parameters

T	number type

Parameters

min	minimal value
range	range of the interval, must be greater than 0

Returns

random number from the interval [min, range)

size_t OpenANN::RandomNumberGenerator::generateIndex

(

size_t

size)

const

Draw an index from a uniform distribution.

Parameters

size	range of the index, must be greater than 0

Returns

random number from the interval [0, size)

template<class C >

void OpenANN::RandomNumberGenerator::generateIndices ( int  n, C &  result, bool  initialized = false  )

inline

Generate a random sequence of indices.

Template Parameters

container

type of result (must support push_back())

Parameters

n	number of indices
result	result container, must be empty if initialized = false
initialized	does the container already contain indices?

int OpenANN::RandomNumberGenerator::generateInt	(	int	min,
		int	range
	)		const

Draw an integer from a uniform distribution.

Parameters

min	minimal value
range	range of the interval, must be greater than 0

Returns

random number from the interval [min, range)

template<class T >

T OpenANN::RandomNumberGenerator::sampleNormalDistribution ( ) const

inline

Draw a sample from a normal distribution with zero mean and variance 1.

We use the Box–Muller transform. In order to draw a random number from the distribution , you have to shift and scale the output of this function:

RandomNumberGenerator rng;
double mu = ...
double sigma = ...
double rn = mu + sigma*rng.sampleNormalDistribution<double>();

Template Parameters

T	number type

Returns

standard normal distributed random number

void OpenANN::RandomNumberGenerator::seed

(

unsigned int

seed)

Set the seed to ensure repeatability.

Note that the seed is set globally, i.e. it might also be overwritten by another part of you program.

Parameters

seed	initial parameter for random number generator

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

• OpenANN/util/Random.h