dart::math::Random Class Reference

#include <Random.hpp>

Public Types
using	GeneratorType = std::mt19937
template<typename FloatType >
using	UniformRealDist = std::uniform_real_distribution< FloatType >
template<typename IntType >
using	UniformIntDist = std::uniform_int_distribution< IntType >
template<typename FloatType >
using	NormalRealDist = std::normal_distribution< FloatType >

Static Public Member Functions
static GeneratorType &	getGenerator ()
	Returns a mutable reference to the random generator. More...
static void	setSeed (unsigned int seed)
	Sets the seed value. More...
static unsigned int	generateSeed (bool applyGeneratedSeed=false)
	Generates a seed value using the default random device. More...
static unsigned int	getSeed ()
template<typename S >
static S	uniform (S min, S max)
	Returns a random number from an uniform distribution. More...
template<typename FixedSizeT >
static FixedSizeT	uniform (typename FixedSizeT::Scalar min, typename FixedSizeT::Scalar max)
	Returns a random vector or matrix from an uniform distribution. More...
template<typename DynamicSizeVectorT >
static DynamicSizeVectorT	uniform (int size, typename DynamicSizeVectorT::Scalar min, typename DynamicSizeVectorT::Scalar max)
	Returns a random vector from an uniform distribution. More...
template<typename DynamicSizeMatrixT >
static DynamicSizeMatrixT	uniform (int rows, int cols, typename DynamicSizeMatrixT::Scalar min, typename DynamicSizeMatrixT::Scalar max)
	Returns a random matrix from an uniform distribution. More...
template<typename S >
static S	normal (S mean, S sigma)
	Returns a random number from a normal distribution. More...

Static Private Member Functions
static unsigned int &	getSeedMutable ()

Member Typedef Documentation

GeneratorType

using dart::math::Random::GeneratorType = std::mt19937

NormalRealDist

template<typename FloatType >

using dart::math::Random::NormalRealDist = std::normal_distribution<FloatType>

UniformIntDist

template<typename IntType >

using dart::math::Random::UniformIntDist = std::uniform_int_distribution<IntType>

UniformRealDist

template<typename FloatType >

using dart::math::Random::UniformRealDist = std::uniform_real_distribution<FloatType>

Member Function Documentation

generateSeed()

unsigned int dart::math::Random::generateSeed ( bool  applyGeneratedSeed = false )

static

Generates a seed value using the default random device.

Parameters

[in]

applyGeneratedSeed

Whether to apply the generated seed.

Returns

The new seed value.

getGenerator()

Random::GeneratorType & dart::math::Random::getGenerator ( )

static

Returns a mutable reference to the random generator.

getSeed()

unsigned int dart::math::Random::getSeed ( )

static

Returns

The current seed value.

getSeedMutable()

unsigned int & dart::math::Random::getSeedMutable ( )

staticprivate

Returns

A mutable reference to the seed.

normal()

template<typename S >

S dart::math::Random::normal ( S  mean, S  sigma  )

static

Returns a random number from a normal distribution.

This template function can generate different scalar types of random numbers as:

• Floating-point number: float, double, long double
• Integer number: [unsigned] short, [unsigned] int, [unsigned] long, [unsigned] long long

Example:

// Generate a random int
int intVal = Random::normal(0, 10);
 
// Generate a random double
double dblVal = Random::normal(0.0, 10.0);

Parameters

[in]	mean	Mean of the normal distribution.
[in]	sigma	Standard deviation of the distribution.

See also

uniform()

setSeed()

void dart::math::Random::setSeed ( unsigned int  seed )

static

Sets the seed value.

The same seed gives the same sequence of random values so that you can regenerate the same sequencial random values as long as you knot the seed value.

uniform() [1/4]

template<typename DynamicSizeMatrixT >

DynamicSizeMatrixT dart::math::Random::uniform ( int  rows, int  cols, typename DynamicSizeMatrixT::Scalar  min, typename DynamicSizeMatrixT::Scalar  max  )

static

Returns a random matrix from an uniform distribution.

This variant is meant to be used for dynamic-size matrix.

Template Parameters

DynamicSizeMatrixT

The type of dynamic-size matrix.

Parameters

[in]	rows	The row size of the matrices.
[in]	cols	The col size of the matrices.
[in]	min	The constant value of the lower bound matrix.
[in]	max	The constant value of the upper bound matrix.

See also

uniform()

uniform() [2/4]

template<typename DynamicSizeVectorT >

DynamicSizeVectorT dart::math::Random::uniform ( int  size, typename DynamicSizeVectorT::Scalar  min, typename DynamicSizeVectorT::Scalar  max  )

static

Returns a random vector from an uniform distribution.

This variant is meant to be used for dynamic-size vector.

Example:

// Generate random matrices
Eigen::MatrixXi matXi = Random::uniform<Eigen::MatrixXi>(0, 10);
Eigen::MatrixXd matXd = Random::uniform<Eigen::MatrixXd>(0.0, 10.0);

Template Parameters

DynamicSizeVectorT

The type of dynamic-size vector.

Parameters

[in]	size	The size of the vectors.
[in]	min	The constant value of the lower bound vector.
[in]	max	The constant value of the upper bound vector.

uniform() [3/4]

template<typename S >

S dart::math::Random::uniform ( S  min, S  max  )

static

Returns a random number from an uniform distribution.

This template function can generate different scalar types of random numbers as:

• Floating-point number: float, double, long double
• Integer number: [unsigned] short, [unsigned] int, [unsigned] long, [unsigned] long long

and vectors and matrices as:

• Fixed-size: Eigen::Vector3i, Eigen::Vector3d, Eigen::Matrix4d, and so on.
• Dynamic-size: Eigen::VectorXi, Eigen::VectorXd, Eigen::MatrixXd, and so on.

Example:

// Generate a random int in [0, 10]
int intVal1 = Random::uniform(0, 10);
int intVal2 = Random::uniform<int>(0, 10);
 
// Generate a random double in [0.0, 10.0)
double dblVal1 = Random::uniform(0.0, 10.0);
double dblVal2 = Random::uniform<double>(0, 10);
 
// Generate a random vector in [lb, ub)
Eigen::Vector3d lb = Eigen::Vector3d::Constant(1);
Eigen::Vector3d ub = Eigen::Vector3d::Constant(4);
Eigen::Vector3d vecVal1 = Random::uniform(lb, ub);
Eigen::Vector3d vecVal2 = Random::uniform<Eigen::Vector3d>(lb, ub);
 
// Generate a random matrix in [lb, ub)
Eigen::Matrix4f lb = Eigen::Matrix4f::Constant(1);
Eigen::Matrix4f ub = Eigen::Matrix4f::Constant(4);
Eigen::Matrix4f vecVal1 = Random::uniform(lb, ub);
Eigen::Matrix4f vecVal2 = Random::uniform<Eigen::Matrix4f>(lb, ub);

Note that the end of the range is closed for integer types (i.e., [int_min, int_max]), but open for floating-point types (i.e., [float_min, float_max)).

Template Parameters

S	The type of random value.

Parameters

[in]	min	Lower bound of the distribution.
[in]	max	Upper bound of the distribution.

See also

normal()

uniform() [4/4]

template<typename FixedSizeT >

FixedSizeT dart::math::Random::uniform ( typename FixedSizeT::Scalar  min, typename FixedSizeT::Scalar  max  )

static

Returns a random vector or matrix from an uniform distribution.

This is a helper function for the case that the each of lower and upper bound has an uniform element value in it. For example, the lower bound is [1, 1, 1] or [-2, -2].

This variant is meant to be used for fixed-size vector or matrix types. For dynamic-size types, please use other variants that takes the size of vector or matrix.

Example:

// Generate random vectors
Eigen::VectorXi vecXi = Random::uniform<Eigen::VectorXi>(0, 10);
Eigen::VectorXd vecXd = Random::uniform<Eigen::VectorXd>(0.0, 10.0);

Template Parameters

FixedSizeT

The type of fixed-size vector or fixed-size matrix.

Parameters

[in]	min	The constant value of the lower bound.
[in]	max	The constant value of the upper bound.

See also

uniform()