edu.ucla.stat.SOCR.distributions Class PoissonDistribution

```java.lang.Object
edu.ucla.stat.SOCR.core.SOCRValueSettable
edu.ucla.stat.SOCR.core.Distribution
edu.ucla.stat.SOCR.distributions.PoissonDistribution
```
All Implemented Interfaces:
IValueSettable, Pluginable, java.util.Observer

`public class PoissonDistributionextends Distribution`

A Java implementation of the Poisson distribution with specified Shift and Mean parameters http://en.wikipedia.org/wiki/Poisson_distribution.

Field Summary

Fields inherited from class edu.ucla.stat.SOCR.core.Distribution
`applet, CONTINUOUS, DISCRETE, MAXMGFXVAL, MAXMGFYVAL, MINMGFXVAL, MIXED, name`

Constructor Summary
`PoissonDistribution()`
Default constructor: creates a Poisson distribution with shift and lambda parameters equal to 0 & 1
`PoissonDistribution(double l)`

`PoissonDistribution(double[] distData)`

`PoissonDistribution(float[] distData)`

```PoissonDistribution(int s, double l)```

Method Summary
` double` `getCDF(double x)`
Compute the cumulative distribution function.
` double` `getDensity(double x)`
Define the Poisson getDensity function
` double` `getLambda()`
Get the lambda paramter
` int` `getLocation()`
Get the Location-Shift paramter
` double` `getMaxDensity()`
Compute the maximum getDensity
` double` `getMean()`
Compute the mean in closed form
` double` `getMGF(double t)`
Computes the moment generating function in closed form for a parameter t which lies in the domain of the distribution.
` double` `getMode()`
Compute the Mode in closed form
` java.lang.String` `getOnlineDescription()`
This method returns an online description of this distribution.
` double` `getPGF(double t)`
Computes the probability generating function in closed form for a parameter t which lies in the domain of the distribution.
` double` `getSD()`
Compute the variance in closed form
` int` `getShift()`

` double` `getVariance()`
Compute the variance in closed form
` void` `initialize()`
used for some subclass to initialize before being used
` double` `inverseCDF(double probability)`
Inverse of the cumulative Poisson distribution function.
` double` `minimum(double[] distData)`
The method finds the minimum of a double array directly copied from ExponentialDistribution.java.
` void` `paramEstimate(double[] distData)`
Parameter estimation function from raw data For some reason this always OVERESTIMATES the SHIFT parameter.
` void` `setLambda(double r)`
Sets the lambda
` void` `setLocation(int s)`
Sets the Location parameter
` void` `setParameter(double l)`
Set the LAMBDA parameter
` void` ```setParameters(int s, double l)```
Set the shift & lambda parameters
` void` `setShift(int s)`

` double` `simulate()`
Simulate a value
` void` `valueChanged()`

Methods inherited from class edu.ucla.stat.SOCR.core.Distribution
`addObserver, betaCDF, comb, factorial, findGFRoot, findRoot, gamma, gammaCDF, getDisplayPane, getDomain, getFailureRate, getGFDerivative, getGFSecondDerivative, getInstance, getLocalHelp, getMean, getMedian, getMgfDomain, getName, getPGFDomain, getQuantile, getSampleMoment, getSOCRDistributionFunctors, getSOCRDistributions, getType, getVariance, logGamma, perm, sampleMean, sampleVar, setApplet, setDomain, setDomain, setMGFDomain, setMGFDomain, setMGFParameters, setMGFParameters, setMGFParameters, setMGFParameters, setParameters, setPGFDomain, setPGFDomain, setPGFParameters, setPGFParameters, setPGFParameters, setPGFParameters, update, valueChanged`

Methods inherited from class edu.ucla.stat.SOCR.core.SOCRValueSettable
`createComponentSetter, createValueSetter, createValueSetter, createValueSetter, createValueSetter, getComponentSetter, getComponentSetters, getValueSetter, getValueSetters`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

PoissonDistribution

`public PoissonDistribution()`
Default constructor: creates a Poisson distribution with shift and lambda parameters equal to 0 & 1

PoissonDistribution

```public PoissonDistribution(int s,
double l)```

PoissonDistribution

`public PoissonDistribution(double l)`

PoissonDistribution

`public PoissonDistribution(double[] distData)`

PoissonDistribution

`public PoissonDistribution(float[] distData)`
Method Detail

initialize

`public void initialize()`
Description copied from class: `Distribution`
used for some subclass to initialize before being used

Overrides:
`initialize` in class `Distribution`

valueChanged

`public void valueChanged()`
Overrides:
`valueChanged` in class `Distribution`

setParameter

`public void setParameter(double l)`
Set the LAMBDA parameter

setParameters

```public void setParameters(int s,
double l)```
Set the shift & lambda parameters

setLocation

`public void setLocation(int s)`
Sets the Location parameter

setLambda

`public void setLambda(double r)`
Sets the lambda

getLocation

`public int getLocation()`
Get the Location-Shift paramter

getLambda

`public double getLambda()`
Get the lambda paramter

getShift

`public int getShift()`

getDensity

`public double getDensity(double x)`
Define the Poisson getDensity function

Specified by:
`getDensity` in class `Distribution`

getMaxDensity

`public double getMaxDensity()`
Compute the maximum getDensity

Overrides:
`getMaxDensity` in class `Distribution`

getMean

`public double getMean()`
Compute the mean in closed form

Overrides:
`getMean` in class `Distribution`

getMode

`public double getMode()`
Compute the Mode in closed form

paramEstimate

`public void paramEstimate(double[] distData)`
Parameter estimation function from raw data For some reason this always OVERESTIMATES the SHIFT parameter. We need a better analytical strategy for estimation of parameters here!

Overrides:
`paramEstimate` in class `Distribution`

setShift

`public void setShift(int s)`

minimum

`public double minimum(double[] distData)`
The method finds the minimum of a double array directly copied from ExponentialDistribution.java. annie che 20060714

getVariance

`public double getVariance()`
Compute the variance in closed form

Overrides:
`getVariance` in class `Distribution`

getSD

`public double getSD()`
Compute the variance in closed form

Overrides:
`getSD` in class `Distribution`

getCDF

`public double getCDF(double x)`
Compute the cumulative distribution function.

Overrides:
`getCDF` in class `Distribution`

getMGF

`public double getMGF(double t)`
Computes the moment generating function in closed form for a parameter t which lies in the domain of the distribution.

Overrides:
`getMGF` in class `Distribution`

getPGF

`public double getPGF(double t)`
Computes the probability generating function in closed form for a parameter t which lies in the domain of the distribution.

Overrides:
`getPGF` in class `Distribution`

inverseCDF

`public double inverseCDF(double probability)`
Inverse of the cumulative Poisson distribution function.

Overrides:
`inverseCDF` in class `Distribution`
Parameters:
`probability` - - a probability value in [0, 1]
Returns:
the value X for which P(x<X).

simulate

`public double simulate()`
Simulate a value

Overrides:
`simulate` in class `Distribution`

getOnlineDescription

`public java.lang.String getOnlineDescription()`
This method returns an online description of this distribution.

Overrides:
`getOnlineDescription` in class `Distribution`