sdsu.algorithms.data
Class Poisson

java.lang.Object
  |
  +--sdsu.algorithms.data.ProbabilityDistribution
        |
        +--sdsu.algorithms.data.DiscreteProbability
              |
              +--sdsu.algorithms.data.Poisson

public class Poisson

extends DiscreteProbability

The Poisson distrubution addresses the question of how many events occur in a unit of time or space. This class is adapted from Smalltalk-80: The language and Its Implementation, Goldberg & Robson, Addison-Wesley, 1983, chapter 21, pages 417-438.

Version:

1.0 10 June 1997

Author:

Roger Whitney (whitney@cs.sdsu.edu)

Constructor Summary

Poisson(double averageEvents)
Returns a Poisson distribution object.

Method Summary

double	density(double numberOfEvents) Returns the probability that numberOfEvents will occur in one unit (time, space).
double	mean() Returns the mean of the distribution
double	nextElement() Returns the number events that occur in simualtion of one unit (of time or space).
double	variance() Returns the variance of the probability distribution

Methods inherited from class sdsu.algorithms.data.DiscreteProbability

distribution

Methods inherited from class sdsu.algorithms.data.ProbabilityDistribution

density

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Poisson

public Poisson(double averageEvents)
        throws OutOfBoundsException

Returns a Poisson distribution object.

Parameters:

averageEvents - the averate number of events happening per unit (time, space).

Throws:

OutOfBoundsException - thrown if averageEvents is not greater than 0.0.

Method Detail

density

public double density(double numberOfEvents)

Returns the probability that numberOfEvents will occur in one unit (time, space).

Parameters:

numberOfEvents - does not make sense unless is integer value.

Overrides:

density in class ProbabilityDistribution

mean

public double mean()

Returns the mean of the distribution

Overrides:

mean in class ProbabilityDistribution

variance

public double variance()

Returns the variance of the probability distribution

Overrides:

variance in class ProbabilityDistribution

nextElement

public double nextElement()

Returns the number events that occur in simualtion of one unit (of time or space).

Overrides:

nextElement in class ProbabilityDistribution