java.lang.Object
- de.uka.ipd.sdq.probfunction.math.apache.impl.AbstractContinousPDF
- - de.uka.ipd.sdq.probfunction.math.apache.impl.ChiSquareDistribution

All Implemented Interfaces:

IChiSquareDistribution, IContinousPDF, IProbabilityDensityFunction, IProbabilityFunction
```
public class ChiSquareDistribution
extends AbstractContinousPDF
implements IChiSquareDistribution
```
Chi-square distribution. The chi-square distribution has a single parameter called the degrees of freedoms.
The implementation of this class is partly based on the information given in [1].
[1] http://en.wikipedia.org/w/index.php?title=Chi-squared_distribution&oldid=461800524

Field Summary
- Fields inherited from class de.uka.ipd.sdq.probfunction.math.apache.impl.AbstractContinousPDF
  internalFunction, sampleDrawer

Constructor Summary

Constructors
Constructor Description

ChiSquareDistribution(int degreesOfFreedom, IRandomGenerator rng)
Default constructor.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`IProbabilityDensityFunction`	`add(IProbabilityDensityFunction pdf)`	Adds two ProbabilityDensityFunctions on a "per value" basis: h(x) = f(x) + g(x) An addition can only be performed if both functions are in the same domain (frequency or time).
`void`	`checkConstrains()`	checks whether the following constraints are fulfilled : the sum of all probabilities is one.
`IProbabilityDensityFunction`	`div(IProbabilityDensityFunction pdf)`	Divides two ProbabilityDensityFunctions on a "per value" basis: h(x) = f(x) / g(x) A division can only be performed if both functions are in the same domain (frequency or time).
`double`	`getArithmeticMeanValue()`	For a probability function, whose domain is integer or real the arithmetic mean - the sum of all measurements divided by the number of observations in the data set - is returned.
`IProbabilityDensityFunction`	`getCumulativeFunction()`	returns the cumulative probability function associated with this probability function.
`double`	`getDegreesOfFreedom()`	Get degrees of freedom.
`IProbabilityDensityFunction`	`getFourierTransform()`	Computes the fourier transform of the probability density function.
`IProbabilityDensityFunction`	`getInverseFourierTransform()`	Computes the inverse fourier transform of the probability density function.
`double`	`getLowerDomainBorder()`	Returns the smallest values of the domain.
`Object`	`getMedian()`	A median is a number dividing the higher half of a sample, a population, or a probability distribution from the lower half.
`Object`	`getPercentile(int p)`	In descriptive statistics, the 'p'th percentile is a scale value for a data series equal to the p/100 quantile.
`double`	`getStandardDeviation()`
`double`	`getVariance()`
`double`	`getXinf()`	Returns xb such that the probability density is 0 everywhere outside the interval [xa, xb],
`double`	`getXsup()`	Returns xa such that the probability density is 0 everywhere outside the interval [xa, xb]
`double`	`greaterThan(IProbabilityDensityFunction pdf)`	Computes the probability that the random variable specified by this PDF is greater than the random variable specified by pdf.
`boolean`	`hasOrderedDomain()`	If the domain of the probability functions is ordered, true is returned; false otherwise.
`double`	`lessThan(IProbabilityDensityFunction pdf)`	Computes the probability that the random variable specified by this PDF is less than the random variable specified by pdf.
`IProbabilityDensityFunction`	`mult(IProbabilityDensityFunction pdf)`	Multiplies two ProbabilityDensityFunctions on a "per value" basis: h(x) = f(x) * g(x) A multiplication can only be performed if both functions are in the same domain (frequency or time).
`double`	`probabilisticEquals(IProbabilityDensityFunction pdf)`	Computes the probability that two random variables characterised by the given PDFs are equal.
`IProbabilityDensityFunction`	`scale(double scalar)`	Scales a ProbabilityDensityFunctions on a "per value" basis: h(x) = a * f(x)
`IProbabilityDensityFunction`	`shiftDomain(double scalar)`	Shifts the domain values of the PDF by the given scalar
`IProbabilityDensityFunction`	`stretchDomain(double scalar)`	Stretches the domain values of the PDF.
`IProbabilityDensityFunction`	`sub(IProbabilityDensityFunction pdf)`	Subtracts two ProbabilityDensityFunctions on a "per value" basis: h(x) = f(x) - g(x) A substraction can only be performed if both functions are in the same domain (frequency or time).

Methods inherited from class de.uka.ipd.sdq.probfunction.math.apache.impl.AbstractContinousPDF
cdf, density, drawSample, getCoefficientOfVariance, getProbabilitySum, getUnit, inverseF, isInFrequencyDomain, isInTimeDomain

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

Methods inherited from interface de.uka.ipd.sdq.probfunction.math.IContinousPDF
cdf, density, getCoefficientOfVariance, inverseF

Methods inherited from interface de.uka.ipd.sdq.probfunction.math.IProbabilityDensityFunction
drawSample

Methods inherited from interface de.uka.ipd.sdq.probfunction.math.IProbabilityFunction
getProbabilitySum, getUnit, isInFrequencyDomain, isInTimeDomain

- Constructor Detail
  - ChiSquareDistribution
```
public ChiSquareDistribution(int degreesOfFreedom,
                             IRandomGenerator rng)
```
    Default constructor.
    
    Parameters:
    
    degreesOfFreedom - the parameter of this distribution, which must be a positive integer
- Method Detail
  - getDegreesOfFreedom
```
public double getDegreesOfFreedom()
```
    Description copied from interface: IChiSquareDistribution
    
    Get degrees of freedom.
    
    Specified by:
    
    getDegreesOfFreedom in interface IChiSquareDistribution
    
    Returns:
  - getVariance
```
public double getVariance()
```
    Specified by:
    
    getVariance in interface IContinousPDF
    
    Overrides:
    
    getVariance in class AbstractContinousPDF
  - getStandardDeviation
```
public double getStandardDeviation()
```
    Specified by:
    
    getStandardDeviation in interface IContinousPDF
  - getXinf
```
public double getXinf()
```
    Description copied from interface: IContinousPDF
    
    Returns xb such that the probability density is 0 everywhere outside the interval [xa, xb],
    
    Specified by:
    
    getXinf in interface IContinousPDF
    
    Returns:
    
    lower limit of support
  - getXsup
```
public double getXsup()
```
    Description copied from interface: IContinousPDF
    
    Returns xa such that the probability density is 0 everywhere outside the interval [xa, xb]
    
    Specified by:
    
    getXsup in interface IContinousPDF
    
    Returns:
    
    upper limit of support
  - add
```
public IProbabilityDensityFunction add(IProbabilityDensityFunction pdf)
                                throws FunctionsInDifferenDomainsException,
                                       UnknownPDFTypeException,
                                       IncompatibleUnitsException
```
    Description copied from interface: IProbabilityDensityFunction
    
    Adds two ProbabilityDensityFunctions on a "per value" basis:
    h(x) = f(x) + g(x)
    An addition can only be performed if both functions are in the same domain (frequency or time). If not a FunctionsInDifferenDomainsException is thrown.
    
    Specified by:
    
    add in interface IProbabilityDensityFunction
    
    Overrides:
    
    add in class AbstractContinousPDF
    
    Parameters:
    
    pdf - g(x), probability density function to add.
    
    Returns:
    
    The sum of this function (f(x)) and pdf (g(x))
    
    Throws:
    
    FunctionsInDifferenDomainsException - Thrown if both functions are in different domains.
    
    UnknownPDFTypeException - Thrown if one of the function is of an unknown type (not SamplePDf or BoxedPDF).
    
    IncompatibleUnitsException - Thrown if both functions have units that do not match.
  - div
```
public IProbabilityDensityFunction div(IProbabilityDensityFunction pdf)
                                throws FunctionsInDifferenDomainsException,
                                       UnknownPDFTypeException,
                                       IncompatibleUnitsException
```
    Description copied from interface: IProbabilityDensityFunction
    
    Divides two ProbabilityDensityFunctions on a "per value" basis:
    h(x) = f(x) / g(x)
    A division can only be performed if both functions are in the same domain (frequency or time). If not a FunctionsInDifferenDomainsException is thrown.
    
    Specified by:
    
    div in interface IProbabilityDensityFunction
    
    Overrides:
    
    div in class AbstractContinousPDF
    
    Parameters:
    
    pdf - g(x), probability density function to divide by.
    
    Returns:
    
    The fraction of this function (f(x)) and pdf (g(x))
    
    Throws:
    
    FunctionsInDifferenDomainsException
    
    UnknownPDFTypeException
    
    IncompatibleUnitsException
  - getCumulativeFunction
```
public IProbabilityDensityFunction getCumulativeFunction()
                                                  throws FunctionNotInTimeDomainException
```
    Description copied from interface: IProbabilityDensityFunction
    
    returns the cumulative probability function associated with this probability function.
    
    Specified by:
    
    getCumulativeFunction in interface IProbabilityDensityFunction
    
    Overrides:
    
    getCumulativeFunction in class AbstractContinousPDF
    
    Returns:
    
    the computed cumulative probability function.
    
    Throws:
    
    FunctionNotInTimeDomainException
  - getFourierTransform
```
public IProbabilityDensityFunction getFourierTransform()
                                                throws FunctionNotInTimeDomainException
```
    Description copied from interface: IProbabilityDensityFunction
    
    Computes the fourier transform of the probability density function. Can only be applied if 'isInTimeDomain()' is true, otherwise a FunctionNotInTimeDomain exception is thrown.
    
    Specified by:
    
    getFourierTransform in interface IProbabilityDensityFunction
    
    Overrides:
    
    getFourierTransform in class AbstractContinousPDF
    
    Returns:
    
    fourier transform of the PDF (in frequency domain)
    
    Throws:
    
    FunctionNotInTimeDomainException
  - getInverseFourierTransform
```
public IProbabilityDensityFunction getInverseFourierTransform()
                                                       throws FunctionNotInFrequencyDomainException
```
    Description copied from interface: IProbabilityDensityFunction
    
    Computes the inverse fourier transform of the probability density function. Can only be applied if 'isInFrequencyDomain()' is true, otherwise a FunctionNotInFrequencyDomainException is thrown.
    
    Specified by:
    
    getInverseFourierTransform in interface IProbabilityDensityFunction
    
    Overrides:
    
    getInverseFourierTransform in class AbstractContinousPDF
    
    Returns:
    
    inverse fourier transform of the PDF (in time domain)
    
    Throws:
    
    FunctionNotInFrequencyDomainException
  - getLowerDomainBorder
```
public double getLowerDomainBorder()
```
    Description copied from interface: IProbabilityDensityFunction
    
    Returns the smallest values of the domain. At the moment this will be zero. However, future implementations might allow arbitrary values here.
    
    Specified by:
    
    getLowerDomainBorder in interface IProbabilityDensityFunction
    
    Returns:
    
    Smallest value of the domain.
  - greaterThan
```
public double greaterThan(IProbabilityDensityFunction pdf)
                   throws ProbabilityFunctionException
```
    Description copied from interface: IProbabilityDensityFunction
    
    Computes the probability that the random variable specified by this PDF is greater than the random variable specified by pdf. Note that the randomvariables have to be independent.
    
    Specified by:
    
    greaterThan in interface IProbabilityDensityFunction
    
    Overrides:
    
    greaterThan in class AbstractContinousPDF
    
    Parameters:
    
    pdf - PDF to compare to.
    
    Returns:
    
    Probability X_this > X_pdf
    
    Throws:
    
    ProbabilityFunctionException
  - lessThan
```
public double lessThan(IProbabilityDensityFunction pdf)
                throws ProbabilityFunctionException
```
    Description copied from interface: IProbabilityDensityFunction
    
    Computes the probability that the random variable specified by this PDF is less than the random variable specified by pdf. Note that the randomvariables have to be independent.
    
    Specified by:
    
    lessThan in interface IProbabilityDensityFunction
    
    Overrides:
    
    lessThan in class AbstractContinousPDF
    
    Parameters:
    
    pdf - PDF to compare to.
    
    Returns:
    
    Probability X_this < X_pdf
    
    Throws:
    
    ProbabilityFunctionException
  - mult
```
public IProbabilityDensityFunction mult(IProbabilityDensityFunction pdf)
                                 throws FunctionsInDifferenDomainsException,
                                        UnknownPDFTypeException,
                                        IncompatibleUnitsException
```
    Description copied from interface: IProbabilityDensityFunction
    
    Multiplies two ProbabilityDensityFunctions on a "per value" basis:
    h(x) = f(x) * g(x)
    A multiplication can only be performed if both functions are in the same domain (frequency or time). If not a FunctionsInDifferenDomainsException is thrown.
    
    Specified by:
    
    mult in interface IProbabilityDensityFunction
    
    Overrides:
    
    mult in class AbstractContinousPDF
    
    Parameters:
    
    pdf - g(x), probability density function to multiply with.
    
    Returns:
    
    The product of this function (f(x)) and pdf (g(x))
    
    Throws:
    
    FunctionsInDifferenDomainsException - Thrown if both functions are in different domains.
    
    UnknownPDFTypeException - Thrown if one of the function is of an unknown type (not SamplePDf or BoxedPDF).
    
    IncompatibleUnitsException - Thrown if both functions have units that do not match.
  - probabilisticEquals
```
public double probabilisticEquals(IProbabilityDensityFunction pdf)
                           throws ProbabilityFunctionException
```
    Description copied from interface: IProbabilityDensityFunction
    
    Computes the probability that two random variables characterised by the given PDFs are equal. Note that the randomvariables have to be independent.
    
    Specified by:
    
    probabilisticEquals in interface IProbabilityDensityFunction
    
    Overrides:
    
    probabilisticEquals in class AbstractContinousPDF
    
    Parameters:
    
    pdf - PDF to compare to.
    
    Returns:
    
    Probability that the two random variables characterised by the PDFs are equal.
    
    Throws:
    
    ProbabilityFunctionException
  - scale
```
public IProbabilityDensityFunction scale(double scalar)
```
    Description copied from interface: IProbabilityDensityFunction
    
    Scales a ProbabilityDensityFunctions on a "per value" basis:
    h(x) = a * f(x)
    
    Specified by:
    
    scale in interface IProbabilityDensityFunction
    
    Overrides:
    
    scale in class AbstractContinousPDF
    
    Parameters:
    
    scalar - a, value to scale with.
    
    Returns:
    
    The scaled function a*f(x)
  - shiftDomain
```
public IProbabilityDensityFunction shiftDomain(double scalar)
                                        throws DomainNotNumbersException
```
    Description copied from interface: IProbabilityDensityFunction
    
    Shifts the domain values of the PDF by the given scalar
    
    Specified by:
    
    shiftDomain in interface IProbabilityDensityFunction
    
    Overrides:
    
    shiftDomain in class AbstractContinousPDF
    
    Returns:
    
    Throws:
    
    DomainNotNumbersException
  - stretchDomain
```
public IProbabilityDensityFunction stretchDomain(double scalar)
```
    Description copied from interface: IProbabilityDensityFunction
    
    Stretches the domain values of the PDF. This is equivalent to the multiplication of the specified random variable by the given scalar.
    
    Specified by:
    
    stretchDomain in interface IProbabilityDensityFunction
    
    Overrides:
    
    stretchDomain in class AbstractContinousPDF
    
    Returns:
  - sub
```
public IProbabilityDensityFunction sub(IProbabilityDensityFunction pdf)
                                throws FunctionsInDifferenDomainsException,
                                       UnknownPDFTypeException,
                                       IncompatibleUnitsException
```
    Description copied from interface: IProbabilityDensityFunction
    
    Subtracts two ProbabilityDensityFunctions on a "per value" basis:
    h(x) = f(x) - g(x)
    A substraction can only be performed if both functions are in the same domain (frequency or time). If not a FunctionsInDifferenDomainsException is thrown.
    
    Specified by:
    
    sub in interface IProbabilityDensityFunction
    
    Overrides:
    
    sub in class AbstractContinousPDF
    
    Parameters:
    
    pdf - g(x), probability density function to substract.
    
    Returns:
    
    The difference of this function (f(x)) and pdf (g(x))
    
    Throws:
    
    FunctionsInDifferenDomainsException - Thrown if both functions are in different domains.
    
    UnknownPDFTypeException - Thrown if one of the function is of an unknown type (not SamplePDf or BoxedPDF).
    
    IncompatibleUnitsException - Thrown if both functions have units that do not match.
  - checkConstrains
```
public void checkConstrains()
                     throws NegativeDistanceException,
                            ProbabilitySumNotOneException,
                            FunctionNotInTimeDomainException,
                            UnitNotSetException,
                            UnitNameNotSetException,
                            InvalidSampleValueException
```
    Description copied from interface: IProbabilityFunction
    
    checks whether the following constraints are fulfilled : the sum of all probabilities is one. all values are greater or equal 0.
    
    Specified by:
    
    checkConstrains in interface IProbabilityFunction
    
    Overrides:
    
    checkConstrains in class AbstractContinousPDF
    
    Throws:
    
    NegativeDistanceException
    
    ProbabilitySumNotOneException
    
    FunctionNotInTimeDomainException
    
    UnitNotSetException
    
    UnitNameNotSetException
    
    InvalidSampleValueException
  - getArithmeticMeanValue
```
public double getArithmeticMeanValue()
                              throws DomainNotNumbersException,
                                     FunctionNotInTimeDomainException
```
    Description copied from interface: IProbabilityFunction
    
    For a probability function, whose domain is integer or real the arithmetic mean - the sum of all measurements divided by the number of observations in the data set - is returned.
    
    Specified by:
    
    getArithmeticMeanValue in interface IProbabilityFunction
    
    Returns:
    
    The arithmetic mean.
    
    Throws:
    
    DomainNotNumbersException
    
    FunctionNotInTimeDomainException
  - getMedian
```
public Object getMedian()
                 throws UnorderedDomainException
```
    Description copied from interface: IProbabilityFunction
    
    A median is a number dividing the higher half of a sample, a population, or a probability distribution from the lower half. The median of a finite list of numbers can be found by arranging all the observations from lowest value to highest value and picking the middle one.
    
    Specified by:
    
    getMedian in interface IProbabilityFunction
    
    Returns:
    
    Object that is the border for the median.
    
    Throws:
    
    UnorderedDomainException
  - getPercentile
```
public Object getPercentile(int p)
                     throws IndexOutOfBoundsException,
                            UnorderedDomainException
```
    Description copied from interface: IProbabilityFunction
    
    In descriptive statistics, the 'p'th percentile is a scale value for a data series equal to the p/100 quantile. Thus:
    * The 1st percentile cuts off lowest 1% of data
    * The 98th percentile cuts off lowest 98% of data
    * The 25th percentile is the first quartile
    * The 50th percentile is the median.
    One definition is that the pth percentile of n ordered values is obtained by first calculating the rank k = p(n+1)/100, rounded to the nearest integer and then taking the value that corresponds to that rank.
    
    Specified by:
    
    getPercentile in interface IProbabilityFunction
    
    Parameters:
    
    p - sets the percentile which shall be computed. p must take values between 0 and 100.
    
    Returns:
    
    Object that is the border for the 'p'th percentile.
    
    Throws:
    
    IndexOutOfBoundsException
    
    UnorderedDomainException
  - hasOrderedDomain
```
public boolean hasOrderedDomain()
```
    Description copied from interface: IProbabilityFunction
    
    If the domain of the probability functions is ordered, true is returned; false otherwise.
    
    Specified by:
    
    hasOrderedDomain in interface IProbabilityFunction
    
    Returns:
    
    True, if the domain is ordered.

Class ChiSquareDistribution

Field Summary

Fields inherited from class de.uka.ipd.sdq.probfunction.math.apache.impl.AbstractContinousPDF

Constructor Summary

Method Summary

Methods inherited from class de.uka.ipd.sdq.probfunction.math.apache.impl.AbstractContinousPDF

Methods inherited from class java.lang.Object

Methods inherited from interface de.uka.ipd.sdq.probfunction.math.IContinousPDF

Methods inherited from interface de.uka.ipd.sdq.probfunction.math.IProbabilityDensityFunction

Methods inherited from interface de.uka.ipd.sdq.probfunction.math.IProbabilityFunction

Constructor Detail

ChiSquareDistribution

Method Detail

getDegreesOfFreedom

getVariance

getStandardDeviation

getXinf

getXsup

add

div

getCumulativeFunction

getFourierTransform

getInverseFourierTransform

getLowerDomainBorder

greaterThan

lessThan

mult

probabilisticEquals

scale

shiftDomain

stretchDomain

sub

checkConstrains

getArithmeticMeanValue

getMedian

getPercentile

hasOrderedDomain