## edu.ucla.stat.SOCR.distributions Class ErlangDistribution

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

`public class ErlangDistributionextends Distribution`

A Java implmentation of the Erlang distribution with specified Scale (scale) and shape (shape) parameters http://mathworld.wolfram.com/ErlangDistribution.html .

Field Summary

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

Constructor Summary
`ErlangDistribution()`
Default constructor: creates an Erlang distribution with scale and shape parameters equal to 1
`ErlangDistribution(double[] distData)`
Constructor: creates an Erlang distribution from a sample data series and estimates the scale (a) and shape (b) parameters.
```ErlangDistribution(double a, int b)```
Constructor: creates an Erlang distribution with scale (a) and shape (b) parameters.
`ErlangDistribution(float[] distData)`
Constructor: creates an Erlang distribution from a sample data series and estimates the scale (a) and shape (b) parameters.

Method Summary
` double` `getCDF(double x)`
Compute the cumulative distribution function.
` double` `getDensity(double x)`
Define the Erlang getDensity function
` 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 mean in closed form
` java.lang.String` `getOnlineDescription()`
This method returns an online description of this distribution.
` double` `getScale()`
Get the scale paramter
` double` `getSD()`
Compute the variance in closed form
` int` `getShape()`
Get the shape parameter
` double` `getVariance()`
Compute the variance in closed form
` void` `initialize()`
used for some subclass to initialize before being used
` void` `paramEstimate(double[] distData)`
Overwrites the method in distribution for estimating parameters
` void` ```setParameters(double a, int b)```
Set the parameters, compute the normalizing constant NormalizingConst, and specifies the interval and partition.
` void` `setScale(double a)`
Sets the scale parameter
` void` `setShape(int b)`
Sets the shape parameter
` 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, getPGF, getPGFDomain, getQuantile, getSampleMoment, getSOCRDistributionFunctors, getSOCRDistributions, getType, getVariance, inverseCDF, logGamma, perm, sampleMean, sampleVar, setApplet, setDomain, setDomain, setMGFDomain, setMGFDomain, setMGFParameters, setMGFParameters, setMGFParameters, setMGFParameters, setParameters, setPGFDomain, setPGFDomain, setPGFParameters, setPGFParameters, setPGFParameters, setPGFParameters, simulate, 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

### ErlangDistribution

`public ErlangDistribution()`
Default constructor: creates an Erlang distribution with scale and shape parameters equal to 1

### ErlangDistribution

```public ErlangDistribution(double a,
int b)```
Constructor: creates an Erlang distribution with scale (a) and shape (b) parameters.

### ErlangDistribution

`public ErlangDistribution(double[] distData)`
Constructor: creates an Erlang distribution from a sample data series and estimates the scale (a) and shape (b) parameters.

### ErlangDistribution

`public ErlangDistribution(float[] distData)`
Constructor: creates an Erlang distribution from a sample data series and estimates the scale (a) and shape (b) parameters.

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`

### setParameters

```public void setParameters(double a,
int b)```
Set the parameters, compute the normalizing constant NormalizingConst, and specifies the interval and partition.

### setScale

`public void setScale(double a)`
Sets the scale parameter

### setShape

`public void setShape(int b)`
Sets the shape parameter

### getScale

`public double getScale()`
Get the scale paramter

### getShape

`public int getShape()`
Get the shape parameter

### getDensity

`public double getDensity(double x)`
Define the Erlang 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 mean in closed form

### paramEstimate

`public void paramEstimate(double[] distData)`
Overwrites the method in distribution for estimating parameters

Overrides:
`paramEstimate` in class `Distribution`

### 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)
throws ParameterOutOfBoundsException```
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`
Throws:
`ParameterOutOfBoundsException`

### getOnlineDescription

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

Overrides:
`getOnlineDescription` in class `Distribution`