thrust::random::normal_distribution

Defined in thrust/random/normal_distribution.h

template<typename RealType = double> class normal_distribution : public detail::normal_distribution_base::type<double>

A normal_distribution random number distribution produces floating point Normally distributed random numbers.

The following code snippet demonstrates examples of using a normal_distribution with a random number engine to produce random values drawn from the Normal distribution with a given mean and variance:

#include <thrust/random/linear_congruential_engine.h>
#include <thrust/random/normal_distribution.h>

int main()
{
  // create a minstd_rand object to act as our source of randomness
  thrust::minstd_rand rng;

  // create a normal_distribution to produce floats from the Normal distribution
  // with mean 2.0 and standard deviation 3.5
  thrust::random::normal_distribution<float> dist(2.0f, 3.5f);

  // write a random number to standard output
  std::cout << dist(rng) << std::endl;

  // write the mean of the distribution, just in case we forgot
  std::cout << dist.mean() << std::endl;

  // 2.0 is printed

  // and the standard deviation
  std::cout << dist.stddev() << std::endl;

  // 3.5 is printed

  return 0;
}

Template Parameters: RealType – The type of floating point number to produce.

Public Types

typedef RealType result_type: The type of the floating point number produced by this normal_distribution.

typedef thrust::pair<RealType, RealType> param_type: The type of the object encapsulating this normal_distribution's parameters.

Public Functions

explicit normal_distribution(RealType mean = 0.0, RealType stddev = 1.0)

This constructor creates a new normal_distribution from two values defining the half-open interval of the distribution.

Parameters

mean – The mean (expected value) of the distribution. Defaults to 0.0.
stddev – The standard deviation of the distribution. Defaults to 1.0.

explicit normal_distribution(const param_type &parm)

This constructor creates a new normal_distribution from a param_type object encapsulating the range of the distribution.

Parameters: parm – A param_type object encapsulating the parameters (i.e., the mean and standard deviation) of the distribution.

void reset(): Calling this member function guarantees that subsequent uses of this normal_distribution do not depend on values produced by any random number generator prior to invoking this function.

template<typename UniformRandomNumberGenerator> result_type operator()(UniformRandomNumberGenerator &urng)

This method produces a new Normal random integer drawn from this normal_distribution's range using a UniformRandomNumberGenerator as a source of randomness.

Parameters: urng – The UniformRandomNumberGenerator to use as a source of randomness.

template<typename UniformRandomNumberGenerator> result_type operator()(UniformRandomNumberGenerator &urng, const param_type &parm)

This method produces a new Normal random integer as if by creating a new normal_distribution from the given param_type object, and calling its operator() method with the given UniformRandomNumberGenerator as a source of randomness.

Parameters

urng – The UniformRandomNumberGenerator to use as a source of randomness.
parm – A param_type object encapsulating the parameters of the normal_distribution to draw from.

result_type mean() const

This method returns the value of the parameter with which this normal_distribution was constructed.

Returns: The mean (expected value) of this normal_distribution's output.

result_type stddev() const

This method returns the value of the parameter with which this normal_distribution was constructed.

Returns: The standard deviation of this uniform_real_distribution's output.

param_type param() const

This method returns a param_type object encapsulating the parameters with which this normal_distribution was constructed.

Returns: A param_type object encapsulating the parameters (i.e., the mean and standard deviation) of this normal_distribution.

void param(const param_type &parm)

This method changes the parameters of this normal_distribution using the values encapsulated in a given param_type object.

Parameters: parm – A param_type object encapsulating the new parameters (i.e., the mean and variance) of this normal_distribution.

result_type min() const

This method returns the smallest floating point number this normal_distribution can potentially produce.

Returns: The lower bound of this normal_distribution's half-open interval.

result_type max() const

This method returns the smallest number larger than largest floating point number this uniform_real_distribution can potentially produce.

Returns: The upper bound of this normal_distribution's half-open interval.