robowflex::RNG Namespace Reference

Collection of methods relating to random sampling. More...

Functions
void	setSeed (unsigned int seed)
	Set the random seed of the underlying generator. More...
double	uniform01 ()
	Generate a random real in [0,1). More...
double	uniformReal (double lower_bound, double upper_bound)
	Generate a random real within given bounds: [lower_bound, upper_bound) More...
int	uniformInt (int lower_bound, int upper_bound)
	Generate a random integer within given bounds: [lower_bound, upper_bound) More...
bool	uniformBool ()
	Generate a random boolean. More...
double	gaussian01 ()
double	gaussian (double mean, double stddev)
	Generate a random real using a normal distribution with given mean and standard deviation. More...
double	gaussian (double stddev)
	Generate a random real using a normal distribution with zero mean and given standard deviation. More...
Eigen::Vector3d	uniformRPY (const Eigen::Vector3d &lbound, const Eigen::Vector3d &ubound)
	Uniform random sampling of Euler roll-pitch-yaw angles within lower bound lbound and upper bound ubound computed value has the order (roll, pitch, yaw). More...
Eigen::Vector3d	uniformRPY (const Eigen::Vector3d &bounds)
	Uniform random sampling of Euler roll-pitch-yaw angles within lower bound lbound and upper bound ubound computed value has the order (roll, pitch, yaw). More...
Eigen::Vector3d	unifromRPY ()
	Uniform random sampling of Euler roll-pitch-yaw angles, roll, yaw in range [-pi, pi) and pitch in range[-pi/2, pi/2) computed value has the order (roll, pitch, yaw). More...
Eigen::Vector3d	uniformVec (const Eigen::Vector3d &lbound, const Eigen::Vector3d &ubound)
	Generate a uniform real vector within given bounds: [lower_bound, upper_bound) More...
Eigen::Vector3d	uniformVec (const Eigen::Vector3d &bounds)
	Generate a uniform real vector within given bounds: [-bounds, bounds) More...
Eigen::Vector3d	gaussianVec (const Eigen::Vector3d &mean, const Eigen::Vector3d &stddev)
	Generate a random real vector using a normal distribution with given mean and standard deviation. More...
Eigen::Vector3d	gaussianVec (const Eigen::Vector3d &stddev)
	Generate a random real vector using a normal distribution with mean zero and standard deviation. More...
template<typename Iter >
Iter	uniformSample (Iter start, Iter end)
	Choose a random element between start and end. More...
template<typename Type >
Type &	uniformSample (std::vector< Type > &vector)
	Choose a random element from a vector. More...

Detailed Description

Collection of methods relating to random sampling.

Function Documentation

gaussian() [1/2]

double robowflex::RNG::gaussian	(	double	mean,
		double	stddev
	)

Generate a random real using a normal distribution with given mean and standard deviation.

Parameters

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

Returns

Sampled number.

Definition at line 47 of file random.cpp.

{
    return gaussian01() * stddev + mean;
}

gaussian() [2/2]

double robowflex::RNG::gaussian

(

double

stddev

)

Generate a random real using a normal distribution with zero mean and given standard deviation.

Parameters

[in]

stddev

Standard deviation of the normal distribution.

Returns

Sampled number.

Definition at line 52 of file random.cpp.

{
    return gaussian01() * stddev;
}

gaussian01()

double robowflex::RNG::gaussian01

(

)

Generate a random real using a normal distribution with mean 0 and variance 1

Returns

Sampled number.

Definition at line 42 of file random.cpp.

{
    return NORMALDIST(GENERATOR);
}

gaussianVec() [1/2]

Eigen::Vector3d robowflex::RNG::gaussianVec	(	const Eigen::Vector3d &	mean,
		const Eigen::Vector3d &	stddev
	)

Generate a random real vector using a normal distribution with given mean and standard deviation.

Parameters

[in]	mean	Mean vector of the normal distribution.
[in]	stddev	Standard deviation vector (diagonal covariance) of the normal distribution.

Returns

Sampled vector.

Definition at line 103 of file random.cpp.

{
    Eigen::Vector3d vec;
    vec[0] = gaussian(mean[0], stddev[0]);
    vec[1] = gaussian(mean[1], stddev[1]);
    vec[2] = gaussian(mean[2], stddev[2]);
    return vec;
}

gaussianVec() [2/2]

Eigen::Vector3d robowflex::RNG::gaussianVec

(

const Eigen::Vector3d &

stddev

)

Generate a random real vector using a normal distribution with mean zero and standard deviation.

Parameters

[in]

stddev

Standard deviation vector (diagonal covariance) of the normal distribution.

Returns

Sampled vector.

Definition at line 112 of file random.cpp.

{
    Eigen::Vector3d vec;
    vec[0] = gaussian(stddev[0]);
    vec[1] = gaussian(stddev[1]);
    vec[2] = gaussian(stddev[2]);
 
    return vec;
}

setSeed()

void robowflex::RNG::setSeed

(

unsigned int

seed

)

Set the random seed of the underlying generator.

Parameters

[in]

seed

Seed to set in generator.

Definition at line 15 of file random.cpp.

{
    GENERATOR.seed(seed);
}

uniform01()

double robowflex::RNG::uniform01

(

)

Generate a random real in [0,1).

Returns

Sampled number.

Definition at line 20 of file random.cpp.

{
    return UNIDIST(GENERATOR);
}

uniformBool()

bool robowflex::RNG::uniformBool

(

)

Generate a random boolean.

Returns

Sampled number.

Definition at line 37 of file random.cpp.

{
    return uniform01() <= 0.5;
}

uniformInt()

int robowflex::RNG::uniformInt	(	int	lower_bound,
		int	upper_bound
	)

Generate a random integer within given bounds: [lower_bound, upper_bound)

Parameters

[in]	lower_bound	Lower bound of uniform distribution.
[in]	upper_bound	Upper bound of uniform distribution.

Returns

Sampled number.

Definition at line 31 of file random.cpp.

{
    auto r = (int)floor(uniformReal((double)lower_bound, (double)(upper_bound)));
    return (r > upper_bound - 1) ? upper_bound - 1 : r;
}

uniformReal()

double robowflex::RNG::uniformReal	(	double	lower_bound,
		double	upper_bound
	)

Generate a random real within given bounds: [lower_bound, upper_bound)

Parameters

[in]	lower_bound	Lower bound of uniform distribution.
[in]	upper_bound	Upper bound of uniform distribution.

Returns

Sampled number.

Definition at line 25 of file random.cpp.

{
    assert(lower_bound <= upper_bound);
    return (upper_bound - lower_bound) * uniform01() + lower_bound;
}

uniformRPY() [1/2]

Eigen::Vector3d robowflex::RNG::uniformRPY

(

const Eigen::Vector3d &

bounds

)

Uniform random sampling of Euler roll-pitch-yaw angles within lower bound lbound and upper bound ubound computed value has the order (roll, pitch, yaw).

Parameters

[in]

bounds

[-bounds, bounds] is lower and upper bound is respectively.

Returns

roll-pitch-yaw vector.

Definition at line 77 of file random.cpp.

{
    return uniformRPY(-bounds, bounds);
}

uniformRPY() [2/2]

Eigen::Vector3d robowflex::RNG::uniformRPY	(	const Eigen::Vector3d &	lbound,
		const Eigen::Vector3d &	ubound
	)

Uniform random sampling of Euler roll-pitch-yaw angles within lower bound lbound and upper bound ubound computed value has the order (roll, pitch, yaw).

Parameters

[in]	lbound	Lower bound for roll pitch yaw.
[in]	ubound	Upper bound for roll pitch yaw.

Returns

roll-pitch-yaw vector.

Definition at line 57 of file random.cpp.

{
    const double phi_min = std::max(-constants::pi, lbound[0]);
    const double chi_min = std::max(-constants::half_pi, lbound[1]);
    const double psi_min = std::max(-constants::pi, lbound[2]);
 
    const double phi_max = std::min(constants::pi, ubound[0]);
    const double chi_max = std::min(constants::half_pi, ubound[1]);
    const double psi_max = std::min(constants::pi, ubound[2]);
 
    Eigen::Vector3d v;
    // From Effective Sampling and Distance Metrics for 3D Rigid Body Path Planning, 2004
    v[0] = uniformReal(phi_min, phi_max);
    v[1] = acos(uniformReal(cos(chi_min + constants::half_pi), cos(chi_max + constants::half_pi))) -
           constants::half_pi;
    v[2] = uniformReal(psi_min, psi_max);
 
    return v;
}

uniformSample() [1/2]

template<typename Iter >

Iter robowflex::RNG::uniformSample	(	Iter	start,
		Iter	end
	)

Choose a random element between start and end.

Parameters

[in]	start	Start iterator.
[in]	end	End iterator.

Returns

Chosen element.

Definition at line 121 of file random.h.

        {
            std::advance(start, uniformInt(0, std::distance(start, end)));
            return start;
        };

uniformSample() [2/2]

template<typename Type >

Type& robowflex::RNG::uniformSample

(

std::vector< Type > &

vector

)

Choose a random element from a vector.

Parameters

[in]

vector

Vector to sample from.

Returns

Chosen element.

Definition at line 132 of file random.h.

        {
            return *uniformSample(vector.begin(), vector.end());
        }

uniformVec() [1/2]

Eigen::Vector3d robowflex::RNG::uniformVec

(

const Eigen::Vector3d &

bounds

)

Generate a uniform real vector within given bounds: [-bounds, bounds)

Parameters

[in]

bounds

Upper and (negative) lower bound vector of uniform distribution.

Returns

Sampled vector.

Definition at line 98 of file random.cpp.

{
    return uniformVec(-bounds, bounds);
}

uniformVec() [2/2]

Eigen::Vector3d robowflex::RNG::uniformVec	(	const Eigen::Vector3d &	lbound,
		const Eigen::Vector3d &	ubound
	)

Generate a uniform real vector within given bounds: [lower_bound, upper_bound)

Parameters

[in]	lbound	Lower bound vector of uniform distribution.
[in]	ubound	Upper bound vector of uniform distribution.

Returns

Sampled vector.

Definition at line 88 of file random.cpp.

{
    Eigen::Vector3d vec;
    vec[0] = uniformReal(lbound[0], ubound[0]);
    vec[1] = uniformReal(lbound[1], ubound[1]);
    vec[2] = uniformReal(lbound[2], ubound[2]);
 
    return vec;
}

unifromRPY()

Eigen::Vector3d robowflex::RNG::unifromRPY

(

)

Uniform random sampling of Euler roll-pitch-yaw angles, roll, yaw in range [-pi, pi) and pitch in range[-pi/2, pi/2) computed value has the order (roll, pitch, yaw).

Returns

roll-pitch-yaw vector.

Definition at line 82 of file random.cpp.

{
    return uniformRPY(Eigen::Vector3d{-constants::pi, -constants::half_pi, -constants::pi},
                      Eigen::Vector3d{constants::pi, constants::half_pi, constants::pi});
}