Class Poisson

java.lang.Object

org.ojalgo.random.RandomNumber

org.ojalgo.random.AbstractDiscrete

org.ojalgo.random.Poisson

All Implemented Interfaces:

Comparable<RandomNumber>, DoubleSupplier, Supplier<Double>, BasicFunction, NullaryFunction<Double>, PrimitiveFunction.Nullary, DiscreteDistribution, Distribution, AccessScalar<Double>, ComparableNumber<RandomNumber>, NumberDefinition

public class Poisson
extends AbstractDiscrete

The Poisson distribution is a discrete probability distribution that expresses the probability of a given number of events occurring in a fixed interval of time and/or space if these events occur with a known average rate and independently of the time since the last event. (The Poisson distribution can also be used for the number of events in other specified intervals such as distance, area or volume.) Distribution of number of points in random point process under certain simple assumptions. Approximation to the binomial distribution when aCount is large and aProbability is small. aLambda = aCount * aProbability.

Nested Class Summary

Nested classes/interfaces inherited from interface BasicFunction

BasicFunction.Differentiable<N,F>, BasicFunction.Integratable<N,F>, BasicFunction.PlainUnary<T,R>

Field Summary

Fields

Modifier and Type	Field	Description
private final double	myLambda

Constructor Summary

Constructors

Constructor	Description
Poisson()
Poisson(double lambda)

Method Summary

Modifier and Type	Method	Description
protected double	generate()
double	getExpected()
double	getProbability(int value)	Probability density function
double	getVariance()	Subclasses must override either getStandardDeviation() or getVariance()!
static Poisson	of(double lambda)

Methods inherited from class RandomNumber

checkProbabilty, compareTo, doubleValue, floatValue, getStandardDeviation, intValue, invoke, longValue, newSampleSet, random, setRandom, setSeed, toString

Methods inherited from class Object

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

Methods inherited from interface Distribution

getStandardDeviation

Methods inherited from interface NullaryFunction

andThen, get, getAsDouble

Methods inherited from interface NumberDefinition

booleanValue, byteValue, shortValue

Field Details

myLambda

private final double myLambda

Constructor Details

Poisson

public Poisson()

Poisson

public Poisson(double lambda)

Method Details

of

public static Poisson of(double lambda)

getExpected

public double getExpected()

getProbability

public double getProbability(int value)

Description copied from interface: DiscreteDistribution

Probability density function

getVariance

public double getVariance()

Description copied from class: RandomNumber

Subclasses must override either getStandardDeviation() or getVariance()!

Specified by:

getVariance in interface Distribution

Overrides:

getVariance in class RandomNumber

See Also:

• Distribution.getStandardDeviation()
• Distribution.getVariance()

generate

protected double generate()

Specified by:

generate in class RandomNumber