gov.sandia.cognition.statistics.distribution

Class BernoulliDistribution

java.lang.Object

gov.sandia.cognition.util.AbstractCloneableSerializable

gov.sandia.cognition.statistics.AbstractDistribution<NumberType>

gov.sandia.cognition.statistics.AbstractClosedFormUnivariateDistribution<java.lang.Number>

gov.sandia.cognition.statistics.AbstractClosedFormIntegerDistribution

gov.sandia.cognition.statistics.distribution.BernoulliDistribution

All Implemented Interfaces:

Vectorizable, ClosedFormComputableDistribution<java.lang.Number>, ClosedFormDiscreteUnivariateDistribution<java.lang.Number>, ClosedFormDistribution<java.lang.Number>, ClosedFormUnivariateDistribution<java.lang.Number>, ComputableDistribution<java.lang.Number>, DiscreteDistribution<java.lang.Number>, Distribution<java.lang.Number>, DistributionWithMean<java.lang.Number>, IntegerDistribution, UnivariateDistribution<java.lang.Number>, CloneableSerializable, java.io.Serializable, java.lang.Cloneable

Direct Known Subclasses:

BernoulliDistribution.CDF, BernoulliDistribution.PMF

@PublicationReference(author="Wikipedia",
                      title="Bernoulli distribution",
                      type=WebPage,
                      year=2009,
                      url="http://en.wikipedia.org/wiki/Bernoulli_distribution")
public class BernoulliDistribution
extends AbstractClosedFormIntegerDistribution
implements ClosedFormDiscreteUnivariateDistribution<java.lang.Number>

A Bernoulli distribution, which takes a value of "1" with probability "p" and value of "0" with probability "1-p". This is also known as flipping a weighted coin. A sum of Bernoulli random variables is a Binomial distribution.

Since:

3.0

Author:

Kevin R. Dixon

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	BernoulliDistribution.CDF CDF of a Bernoulli distribution.
static class	BernoulliDistribution.PMF PMF of the Bernoulli distribution.

Field Summary

Fields

Modifier and Type	Field and Description
static double	DEFAULT_P Default Bernoulli parameter, 0.5

Constructor Summary

Constructors

Constructor and Description
BernoulliDistribution() Creates a new instance of BernoulliDistribution
BernoulliDistribution(BernoulliDistribution other) Copy Constructor
BernoulliDistribution(double p) Creates a new instance of BernoulliDistribution

Method Summary

Modifier and Type	Method and Description
void	convertFromVector(Vector parameters) Converts the object from a Vector of parameters.
Vector	convertToVector() Converts the object to a vector.
BernoulliDistribution.CDF	getCDF() Gets the CDF of a scalar distribution.
IntegerSpan	getDomain() Returns an object that allows an iteration through the domain (x-axis, independent variable) of the Distribution
int	getDomainSize() Gets the size of the domain.
java.lang.Integer	getMaxSupport() Gets the minimum support (domain or input) of the distribution.
java.lang.Double	getMean() Gets the arithmetic mean, or "first central moment" or "expectation", of the distribution.
double	getMeanAsDouble() Gets the mean of the distribution as a double.
java.lang.Integer	getMinSupport() Gets the minimum support (domain or input) of the distribution.
double	getP() Getter for p
BernoulliDistribution.PMF	getProbabilityFunction() Gets the distribution function associated with this Distribution, either the PDF or PMF.
double	getVariance() Gets the variance of the distribution.
boolean	sampleAsBoolean(java.util.Random random) Samples from the Bernoulli distribution as a boolean.
int	sampleAsInt(java.util.Random random) Draws a single random sample from the distribution as an int.
void	sampleInto(java.util.Random random, int sampleCount, java.util.Collection<? super java.lang.Number> output) Draws multiple random samples from the distribution and puts the result into the given collection.
void	setP(double p) Setter for p
java.lang.String	toString()

Methods inherited from class gov.sandia.cognition.statistics.AbstractClosedFormIntegerDistribution

sampleAsInts, sampleInto

Methods inherited from class gov.sandia.cognition.statistics.AbstractClosedFormUnivariateDistribution

clone

Methods inherited from class gov.sandia.cognition.statistics.AbstractDistribution

sample, sample

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface gov.sandia.cognition.statistics.Distribution

sample, sample

Methods inherited from interface gov.sandia.cognition.math.matrix.Vectorizable

clone

Field Detail

DEFAULT_P

public static final double DEFAULT_P

Default Bernoulli parameter, 0.5

See Also:

Constant Field Values

Constructor Detail

BernoulliDistribution

public BernoulliDistribution()

Creates a new instance of BernoulliDistribution

BernoulliDistribution

public BernoulliDistribution(double p)

Creates a new instance of BernoulliDistribution

Parameters:

p - Bernoulli parameter, where the distribution takes value "1" with probability "p" and value "0" with probability 1-p.

BernoulliDistribution

public BernoulliDistribution(BernoulliDistribution other)

Copy Constructor

Parameters:

other - BernoulliDistribution to copy

Method Detail

getMean

public java.lang.Double getMean()

Description copied from interface: DistributionWithMean

Gets the arithmetic mean, or "first central moment" or "expectation", of the distribution.

Specified by:

getMean in interface DistributionWithMean<java.lang.Number>

Returns:

Mean of the distribution.

getMeanAsDouble

public double getMeanAsDouble()

Description copied from interface: UnivariateDistribution

Gets the mean of the distribution as a double.

Specified by:

getMeanAsDouble in interface UnivariateDistribution<java.lang.Number>

Returns:

The mean as a double.

getMinSupport

public java.lang.Integer getMinSupport()

Description copied from interface: UnivariateDistribution

Gets the minimum support (domain or input) of the distribution.

Specified by:

getMinSupport in interface UnivariateDistribution<java.lang.Number>

Returns:

Minimum support.

getMaxSupport

public java.lang.Integer getMaxSupport()

Description copied from interface: UnivariateDistribution

Gets the minimum support (domain or input) of the distribution.

Specified by:

getMaxSupport in interface UnivariateDistribution<java.lang.Number>

Returns:

Minimum support.

sampleInto

public void sampleInto(java.util.Random random,
                       int sampleCount,
                       java.util.Collection<? super java.lang.Number> output)

Description copied from interface: Distribution

Draws multiple random samples from the distribution and puts the result into the given collection.

Specified by:

sampleInto in interface Distribution<java.lang.Number>

Parameters:

random - Random number generator to use.

sampleCount - The number of samples to draw. Cannot be negative.

output - The collection to add the samples into.

sampleAsInt

public int sampleAsInt(java.util.Random random)

Description copied from interface: IntegerDistribution

Draws a single random sample from the distribution as an int.

Specified by:

sampleAsInt in interface IntegerDistribution

Parameters:

random - The random number generator to use.

Returns:

A sample from the distribution.

sampleAsBoolean

public boolean sampleAsBoolean(java.util.Random random)

Samples from the Bernoulli distribution as a boolean.

Parameters:

random - The random number generator to use.

Returns:

A true or false value sampled from the distribution. The value is true with probability p.

convertToVector

public Vector convertToVector()

Description copied from interface: Vectorizable

Converts the object to a vector.

Specified by:

convertToVector in interface Vectorizable

Returns:

The Vector form of the object.

convertFromVector

public void convertFromVector(Vector parameters)

Description copied from interface: Vectorizable

Converts the object from a Vector of parameters.

Specified by:

convertFromVector in interface Vectorizable

Parameters:

parameters - The parameters to incorporate.

getVariance

public double getVariance()

Description copied from interface: UnivariateDistribution

Gets the variance of the distribution. This is sometimes called the second central moment by more pedantic people, which is equivalent to the square of the standard deviation.

Specified by:

getVariance in interface UnivariateDistribution<java.lang.Number>

Returns:

Variance of the distribution.

getDomain

public IntegerSpan getDomain()

Description copied from interface: DiscreteDistribution

Returns an object that allows an iteration through the domain (x-axis, independent variable) of the Distribution

Specified by:

getDomain in interface DiscreteDistribution<java.lang.Number>

Returns:

Collection that enumerates each value that the domain can take

getDomainSize

public int getDomainSize()

Description copied from interface: DiscreteDistribution

Gets the size of the domain.

Specified by:

getDomainSize in interface DiscreteDistribution<java.lang.Number>

Returns:

The size of the domain.

getP

public double getP()

Getter for p

Returns:

Bernoulli parameter, where the distribution takes value "1" with probability "p" and value "0" with probability 1-p.

setP

public void setP(double p)

Setter for p

Parameters:

p - Bernoulli parameter, where the distribution takes value "1" with probability "p" and value "0" with probability 1-p.

getCDF

public BernoulliDistribution.CDF getCDF()

Description copied from interface: UnivariateDistribution

Gets the CDF of a scalar distribution.

Specified by:

getCDF in interface ClosedFormUnivariateDistribution<java.lang.Number>

Specified by:

getCDF in interface UnivariateDistribution<java.lang.Number>

Returns:

CDF of the scalar distribution.

getProbabilityFunction

public BernoulliDistribution.PMF getProbabilityFunction()

Description copied from interface: ComputableDistribution

Gets the distribution function associated with this Distribution, either the PDF or PMF.

Specified by:

getProbabilityFunction in interface ComputableDistribution<java.lang.Number>

Specified by:

getProbabilityFunction in interface DiscreteDistribution<java.lang.Number>

Returns:

Distribution function associated with this Distribution.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object