de.uka.ipd.sdq.probfunction.math
Interface IProbabilityFunction

All Known Subinterfaces:

IBoxedPDF, IProbabilityDensityFunction, IProbabilityMassFunction, ISamplePDF

All Known Implementing Classes:

BoxedPDFImpl, ProbabilityDensityFunctionImpl, ProbabilityFunctionImpl, ProbabilityMassFunctionImpl, SamplePDFImpl

public interface IProbabilityFunction

A ProbabilityFunction describes a random variable. For each probability function there is a set of stochastic measures that can be derived.

Author:

ihssane, jens

Method Summary

void	checkConstrains() checks whether the following constraints are fulfilled : the sum of all probabilities is one.
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.
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	getProbabilitySum() Computes the sum of all probabilities specified in the function.
IUnit	getUnit() Returns the unit of the probability functions domain.
boolean	hasOrderedDomain() If the domain of the probability functions is ordered, true is returned; false otherwise.
boolean	isInFrequencyDomain() True, if the probability density function is in the frequency domain (frequency domain graph shows how much of the signal lies within each given frequency band over a range of frequencies).
boolean	isInTimeDomain() True, if the probability density function is the time domain (a time domain graph shows how a signal changes over time).

Method Detail

getMedian

Object getMedian()
                 throws UnorderedDomainException

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.

Returns:

Object that is the border for the median.

Throws:

UnorderedDomainException

getArithmeticMeanValue

double getArithmeticMeanValue()
                              throws DomainNotNumbersException,
                                     FunctionNotInTimeDomainException

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.

Returns:

The arithmetic mean.

Throws:

DomainNotNumbersException

FunctionNotInTimeDomainException

getPercentile

Object getPercentile(int p)
                     throws IndexOutOfBoundsException,
                            UnorderedDomainException

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.

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

getProbabilitySum

double getProbabilitySum()
                         throws FunctionNotInTimeDomainException

Computes the sum of all probabilities specified in the function. For pdfs this is the area under the graph; for pmfs the sum of all probabilities.

Returns:

Sum of all probabilities in the function.

Throws:

FunctionNotInTimeDomainException

getUnit

IUnit getUnit()

Returns the unit of the probability functions domain.

Returns:

unit of the probability functions domain.

isInTimeDomain

boolean isInTimeDomain()

True, if the probability density function is the time domain (a time domain graph shows how a signal changes over time). This means that it is not a result of a Fourier transform.

Returns:

True, if in time domain; false otherwise.

isInFrequencyDomain

boolean isInFrequencyDomain()

True, if the probability density function is in the frequency domain (frequency domain graph shows how much of the signal lies within each given frequency band over a range of frequencies). This means it is the result of a Fourier transformation.

Returns:

True, if in frequency domain, false otherwise.

hasOrderedDomain

boolean hasOrderedDomain()

If the domain of the probability functions is ordered, true is returned; false otherwise.

Returns:

True, if the domain is ordered.

checkConstrains

void checkConstrains()
                     throws NegativeDistanceException,
                            ProbabilitySumNotOneException,
                            FunctionNotInTimeDomainException,
                            UnitNotSetException,
                            UnitNameNotSetException,
                            InvalidSampleValueException

checks whether the following constraints are fulfilled : the sum of all probabilities is one. all values are greater or equal 0.

Throws:

NegativeDistanceException

ProbabilitySumNotOneException

FunctionNotInTimeDomainException

UnitNotSetException

UnitNameNotSetException

InvalidSampleValueException