NAME¶

mlpack::distribution::DiscreteDistribution - A discrete distribution where the only observations are discrete observations.

SYNOPSIS¶

Public Member Functions¶

DiscreteDistribution () Default constructor, which creates a distribution that has no observations. DiscreteDistribution (const size_t numObservations) Define the discrete distribution as having numObservations possible observations. DiscreteDistribution (const arma::vec &probabilities) Define the discrete distribution as having the given probabilities for each observation. size_t Dimensionality () const Get the dimensionality of the distribution. void Estimate (const arma::mat &observations) Estimate the probability distribution directly from the given observations. void Estimate (const arma::mat &observations, const arma::vec & probabilities) Estimate the probability distribution from the given observations, taking into account the probability of each observation actually being from this distribution. const arma::vec & Probabilities () const Return the vector of probabilities. arma::vec & Probabilities () Modify the vector of probabilities. double Probability (const arma::vec &observation) const Return the probability of the given observation. arma::vec Random () const Return a randomly generated observation (one-dimensional vector; one observation) according to the probability distribution defined by this object. std::string ToString () const

Private Attributes¶

arma::vec probabilities

Detailed Description¶

A discrete distribution where the only observations are discrete observations. This is useful (for example) with discrete Hidden Markov Models, where observations are non-negative integers representing specific emissions. No bounds checking is performed for observations, so if an invalid observation is passed (i.e. observation > numObservations), a crash will probably occur. This distribution only supports one-dimensional observations, so when passing an arma::vec as an observation, it should only have one dimension (vec.n_rows == 1). Any additional dimensions will simply be ignored. Note: Definition at line 53 of file discrete_distribution.hpp.

Constructor & Destructor Documentation¶

mlpack::distribution::DiscreteDistribution::DiscreteDistribution () [inline]¶

Default constructor, which creates a distribution that has no observations. Definition at line 59 of file discrete_distribution.hpp.

mlpack::distribution::DiscreteDistribution::DiscreteDistribution (const size_tnumObservations) [inline]¶

Define the discrete distribution as having numObservations possible observations. The probability in each state will be set to (1 / numObservations). Parameters: Definition at line 69 of file discrete_distribution.hpp.

mlpack::distribution::DiscreteDistribution::DiscreteDistribution (const arma::vec &probabilities) [inline]¶

Define the discrete distribution as having the given probabilities for each observation. Parameters: Definition at line 79 of file discrete_distribution.hpp.

Member Function Documentation¶

size_t mlpack::distribution::DiscreteDistribution::Dimensionality () const [inline]¶

Get the dimensionality of the distribution. Definition at line 95 of file discrete_distribution.hpp.

void mlpack::distribution::DiscreteDistribution::Estimate (const arma::mat &observations)¶

Estimate the probability distribution directly from the given observations. If any of the observations is greater than numObservations, a crash is likely to occur. Parameters:

void mlpack::distribution::DiscreteDistribution::Estimate (const arma::mat &observations, const arma::vec &probabilities)¶

Estimate the probability distribution from the given observations, taking into account the probability of each observation actually being from this distribution. Parameters:

const arma::vec& mlpack::distribution::DiscreteDistribution::Probabilities () const [inline]¶

Return the vector of probabilities. Definition at line 153 of file discrete_distribution.hpp. References probabilities.

arma::vec& mlpack::distribution::DiscreteDistribution::Probabilities () [inline]¶

Modify the vector of probabilities. Definition at line 155 of file discrete_distribution.hpp. References probabilities.

double mlpack::distribution::DiscreteDistribution::Probability (const arma::vec &observation) const [inline]¶

Return the probability of the given observation. If the observation is greater than the number of possible observations, then a crash will probably occur -- bounds checking is not performed. Parameters: Returns: Definition at line 105 of file discrete_distribution.hpp. References mlpack::Log::Debug, and probabilities.

arma::vec mlpack::distribution::DiscreteDistribution::Random () const¶

Return a randomly generated observation (one-dimensional vector; one observation) according to the probability distribution defined by this object. Returns:

std::string mlpack::distribution::DiscreteDistribution::ToString () const¶

Member Data Documentation¶

arma::vec mlpack::distribution::DiscreteDistribution::probabilities [private]¶

Definition at line 163 of file discrete_distribution.hpp. Referenced by Probabilities(), and Probability().

Author¶

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