Package de.uka.ipd.sdq.probfunction.math

Interface ISamplePDF

All Superinterfaces:

IProbabilityDensityFunction, IProbabilityFunction

All Known Implementing Classes:

SamplePDFImpl

public interface ISamplePDF
extends IProbabilityDensityFunction

For the implementation of the SamplePDF, we used a simplified version of probability density functions to ease the following computations and analyses. The pdf is approximated by a number of sampling points, which are seperated by a fixed distance. Each sampling point contains the probability for a sample to lie in a certain interval. For example, if we have a pdf with a distance of 5 between the sampling points, the probability stored in the first point is for the interval [0, 2.5), the second for the interval [2.5, 7.5), and so on. The probabilities of the intervals [a, b) are derived from the original pdf by computing difference F(b) - F(a) of its integral, which is the the probability for a sample lying in the interval.

Method Summary

Modifier and Type	Method	Description
void	expand(int newSize)	Increases the number of sampling points.
double	getDistance()	Returns the distance between the sampling points.
org.apache.commons.math.complex.Complex	getFillValue()	Returns the value used to fill unset sampling points at the end of the function.
double	getFillValueAsDouble()	Returns the real part of the value used to fill unset sampling points at the end of the function.
ISamplePDF	getFunctionWithNewDistance(double distance)	Creates a new SamplePDF that describes the same PDF, but whose sampling points are computed according to a new distance.
org.apache.commons.math.complex.Complex	getValue(int pos)
Double	getValueAsDouble(int pos)
List<org.apache.commons.math.complex.Complex>	getValues()	Returns the sampling points of the function as complex numbers.
List<Double>	getValuesAsDouble()	Returns the real part of the function's samples.
int	numberOfSamples()	The number of samples used to approximate the pdf.
void	setFillValue(double fillValue)	Sets the real part of the fill value to fillValue and the imaginary part to zero.
void	setFillValue(org.apache.commons.math.complex.Complex fillValue)	Sets the new fill value.
void	setValues(List<org.apache.commons.math.complex.Complex> values, boolean isInFrequencyDomain)	Sets the sampling points of the function.
void	setValuesAsDouble(List<Double> values)	/** Sets the sampling points of the function.

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

add, div, drawSample, getCumulativeFunction, getFourierTransform, getInverseFourierTransform, getLowerDomainBorder, greaterThan, lessThan, mult, probabilisticEquals, scale, shiftDomain, stretchDomain, sub

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

checkConstrains, getArithmeticMeanValue, getMedian, getPercentile, getProbabilitySum, getUnit, hasOrderedDomain, isInFrequencyDomain, isInTimeDomain

Method Detail

expand

void expand(int newSize)
     throws SizeTooSmallException

Increases the number of sampling points. The new enries are filled with the value returned by 'getFillValue()'. The values are added at the end of the pdf.

Parameters:

newSize - the new number of sampling points. If newSize is smaller than the original size, an exception is thrown.

Throws:

SizeTooSmallException - Thrown if newSize is small than the current number of elements.

getDistance

double getDistance()

Returns the distance between the sampling points.

Returns:

distance between the sampling points.

getFunctionWithNewDistance

ISamplePDF getFunctionWithNewDistance(double distance)
                               throws NegativeDistanceException,
                                      FunctionNotInTimeDomainException

Creates a new SamplePDF that describes the same PDF, but whose sampling points are computed according to a new distance.

Parameters:

distance - Distance of the new function.

Returns:

A new SamplePDF that describes the same PDF, but whose sampling points are adjusted to the new distance.

Throws:

FunctionNotInTimeDomainException

NegativeDistanceException

getValuesAsDouble

List<Double> getValuesAsDouble()

Returns the real part of the function's samples. Copy only!

Returns:

Samples of the function.

getValues

List<org.apache.commons.math.complex.Complex> getValues()

Returns the sampling points of the function as complex numbers. Copy only!

Returns:

Samples of the function.

getValue

org.apache.commons.math.complex.Complex getValue(int pos)

getValueAsDouble

Double getValueAsDouble(int pos)

setValuesAsDouble

void setValuesAsDouble(List<Double> values)

/** Sets the sampling points of the function. As the values are doubles, only the real part of the complex numbers is set. The imaginary part is set to zero. The function is automatically set to the time domain. Note: The sum of all values has to be one, otherwise a ProbabilitySumNotOneException is thrown.

Parameters:

values - a new list of sampling points.

Throws:

ProbabilitySumNotOneException - Thrown, if the sum of the values is not one.

setValues

void setValues(List<org.apache.commons.math.complex.Complex> values,
               boolean isInFrequencyDomain)

Sets the sampling points of the function.

Parameters:

values - a new list of sampling points.

Throws:

ProbabilitySumNotOneException - Thrown, if the sum of the real part of the values is not one, if the function is in the time domain (isInFrequencyDomain == false).

getFillValueAsDouble

double getFillValueAsDouble()

Returns the real part of the value used to fill unset sampling points at the end of the function.

Returns:

Real part of the fill value.

getFillValue

org.apache.commons.math.complex.Complex getFillValue()

Returns the value used to fill unset sampling points at the end of the function.

Returns:

Fill value.

setFillValue

void setFillValue(double fillValue)

Sets the real part of the fill value to fillValue and the imaginary part to zero.

Parameters:

fillValue - the real part of the new fill value.

setFillValue

void setFillValue(org.apache.commons.math.complex.Complex fillValue)

Sets the new fill value.

Parameters:

fillValue - New fill value.

numberOfSamples

int numberOfSamples()

The number of samples used to approximate the pdf.

Returns:

Number of Samples.