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

Class ProbabilityMassFunctionImpl

java.lang.Object

de.uka.ipd.sdq.probfunction.math.impl.ProbabilityFunctionImpl

de.uka.ipd.sdq.probfunction.math.impl.ProbabilityMassFunctionImpl

All Implemented Interfaces:

IProbabilityFunction, IProbabilityMassFunction

public class ProbabilityMassFunctionImpl
extends ProbabilityFunctionImpl
implements IProbabilityMassFunction

Field Summary

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

pfFactory, randomGenerator

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	ProbabilityMassFunctionImpl(List<ISample> samples, IUnit unit, boolean hasOrderedDomain, boolean isInFrequencyDomain, IRandomGenerator generator)

Method Summary

Modifier and Type	Method	Description
IProbabilityMassFunction	add(IProbabilityMassFunction pmf)	Adds the probabilities of two probability mass functions (pmf) on a 'per value' basis. h(x) = f(x) + g(x) (f = this, g = parameter pmf) For the addition, the domains of both pmfs have to be equal.
void	checkConstrains()	checks whether the following constraints are fulfilled : the sum of all probabilities is one.
IProbabilityMassFunction	div(IProbabilityMassFunction pmf)	Divides the probabilities of two probability mass functions (pmf) on a 'per value' basis. h(x) = f(x) / g(x) (f = this, g = parameter pmf) For the division, the domains of both pmfs have to be equal.
Object	drawSample()	Generates a random number of the probability function's domain, whose distribution is defined by the probability function.
boolean	equals(Object obj)
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.
IProbabilityMassFunction	getCumulativeFunction()	returns the cumulative probability function associated with this probability function.
IProbabilityMassFunction	getFourierTramsform()	Computes the Fourier transform of the probability mass function.
IProbabilityMassFunction	getInverseFourierTransform()	Computes the inverse Fourier transform of the probability mass function.
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.
List<ISample>	getSamples()	List of samples describing the pmf.
boolean	haveSameDomain(IProbabilityMassFunction pmf)	Add all values from valuesOther to valuesThis that have not been there before.
IProbabilityMassFunction	mult(IProbabilityMassFunction pmf)	Multiplies the probabilities of two probability mass functions (pmf) on a 'per value' basis. h(x) = f(x) * g(x) (f = this, g = parameter pmf) For the multiplication, the domains of both pmfs have to be equal.
IProbabilityMassFunction	scale(double scalar)	Scales the probabilities of a probability mass functions (pmf) on a 'per value' basis. h(x) = a * f(x) (f = this, a = parameter scalar)
void	setSamples(List<ISample> samples)	List of samples describing the pmf.
IProbabilityMassFunction	shiftDomain(double scalar)	Shifts each value of the PMF by the given scalar (i.e., adds the given scalar to each value).
IProbabilityMassFunction	stretchDomain(double scalar)	Stretches the domain of the PMF by the given scalar (i.e, multiplies each value with the given scalar).
IProbabilityMassFunction	sub(IProbabilityMassFunction pmf)	Substracts the probabilities of two probability mass functions (pmf) on a 'per value' basis. h(x) = f(x) - g(x) (f = this, g = parameter pmf) For the substraction, the domains of both pmfs have to be equal.

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

getRandomGenerator, getUnit, hasOrderedDomain, isInFrequencyDomain, isInTimeDomain, setInFrequencyDomain, setRandomGenerator, setUnit

Methods inherited from class java.lang.Object

clone, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

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

getUnit, hasOrderedDomain, isInFrequencyDomain, isInTimeDomain

Constructor Detail

ProbabilityMassFunctionImpl

protected ProbabilityMassFunctionImpl(List<ISample> samples,
                                      IUnit unit,
                                      boolean hasOrderedDomain,
                                      boolean isInFrequencyDomain,
                                      IRandomGenerator generator)

Method Detail

add

public IProbabilityMassFunction add(IProbabilityMassFunction pmf)
                             throws DifferentDomainsException

Description copied from interface: IProbabilityMassFunction

Adds the probabilities of two probability mass functions (pmf) on a 'per value' basis.
h(x) = f(x) + g(x) (f = this, g = parameter pmf)
For the addition, the domains of both pmfs have to be equal. This means that

* the value objects of the pmf's samples have to be of the same class and * for each value object of the samples in function f (this) there is exactly one equal value object in the samples of function g (pmf) and vice versa. Here, equal means that Object.equal(...) returns true for both objects.
If the domain of both functions are not equal, a DifferentDomainsException is thrown.

Specified by:

add in interface IProbabilityMassFunction

Parameters:

pmf - Function to add.

Returns:

A new pmf that contains the sum of both.

Throws:

DifferentDomainsException - if the domains of both function differ.

mult

public IProbabilityMassFunction mult(IProbabilityMassFunction pmf)
                              throws DifferentDomainsException

Description copied from interface: IProbabilityMassFunction

Multiplies the probabilities of two probability mass functions (pmf) on a 'per value' basis.
h(x) = f(x) * g(x) (f = this, g = parameter pmf)
For the multiplication, the domains of both pmfs have to be equal. This means that

* the value objects of the pmf's samples have to be of the same class and * for each value object of the samples in function f (this) there is exactly one equal value object in the samples of function g (pmf) and vice versa. Here, equal means that Object.equal(...) returns true for both objects.
If the domain of both functions are not equal, a DifferentDomainsException is thrown.

Specified by:

mult in interface IProbabilityMassFunction

Parameters:

pmf - Function to multiply with.

Returns:

A new pmf that contains the product of both.

Throws:

DifferentDomainsException - if the domains of both function differ.

scale

public IProbabilityMassFunction scale(double scalar)

Description copied from interface: IProbabilityMassFunction

Scales the probabilities of a probability mass functions (pmf) on a 'per value' basis.
h(x) = a * f(x) (f = this, a = parameter scalar)

Specified by:

scale in interface IProbabilityMassFunction

Parameters:

scalar - the value to scale the probabilities.

Returns:

A new pmf that contains the scaled probabilities.

div

public IProbabilityMassFunction div(IProbabilityMassFunction pmf)
                             throws DifferentDomainsException

Description copied from interface: IProbabilityMassFunction

Divides the probabilities of two probability mass functions (pmf) on a 'per value' basis.
h(x) = f(x) / g(x) (f = this, g = parameter pmf)
For the division, the domains of both pmfs have to be equal. This means that

* the value objects of the pmf's samples have to be of the same class and * for each value object of the samples in function f (this) there is exactly one equal value object in the samples of function g (pmf) and vice versa. Here, equal means that Object.equal(...) returns true for both objects.
If the domain of both functions are not equal, a DifferentDomainsException is thrown.

Specified by:

div in interface IProbabilityMassFunction

Parameters:

pmf - Function to divide by.

Returns:

A new pmf that contains the fraction of both.

Throws:

DifferentDomainsException - if the domains of both function differ.

sub

public IProbabilityMassFunction sub(IProbabilityMassFunction pmf)
                             throws DifferentDomainsException

Description copied from interface: IProbabilityMassFunction

Substracts the probabilities of two probability mass functions (pmf) on a 'per value' basis.
h(x) = f(x) - g(x) (f = this, g = parameter pmf)
For the substraction, the domains of both pmfs have to be equal. This means that

* the value objects of the pmf's samples have to be of the same class and * for each value object of the samples in function f (this) there is exactly one equal value object in the samples of function g (pmf) and vice versa. Here, equal means that Object.equal(...) returns true for both objects.
If the domain of both functions are not equal, a DifferentDomainsException is thrown.

Specified by:

sub in interface IProbabilityMassFunction

Parameters:

pmf - Function to substract.

Returns:

A new pmf that contains the difference of both.

Throws:

DifferentDomainsException - if the domains of both function differ.

haveSameDomain

public boolean haveSameDomain(IProbabilityMassFunction pmf)

Add all values from valuesOther to valuesThis that have not been there before. Afterwards, valuesThis should contain all values of valuesOther (and possibly more)

Specified by:

haveSameDomain in interface IProbabilityMassFunction

Parameters:

valuesThis -

valuesOther -

Returns:

getFourierTramsform

public IProbabilityMassFunction getFourierTramsform()

Description copied from interface: IProbabilityMassFunction

Computes the Fourier transform of the probability mass function. Note, that you should only use this function if you really know what you are doing, as this doesn't make sense in many cases for pmfs!

Can only be applied if 'isInTimeDomain()' is true, otherwise a FunctionNotInTimeDomainException is thrown.

Specified by:

getFourierTramsform in interface IProbabilityMassFunction

Returns:

Fourier transform of pmf (in time domain).

getInverseFourierTransform

public IProbabilityMassFunction getInverseFourierTransform()

Description copied from interface: IProbabilityMassFunction

Computes the inverse Fourier transform of the probability mass function. Note, that you should only use this function if you really know what you are doing, as this doesn't make sense in many cases for pmfs!

Can only be applied if 'isInFrequencyDomain()' is true, otherwise a FunctionNotInFrequencyDomainException is thrown.

Specified by:

getInverseFourierTransform in interface IProbabilityMassFunction

Returns:

Fourier transform of pmf (in time domain).

getSamples

public List<ISample> getSamples()

Description copied from interface: IProbabilityMassFunction

List of samples describing the pmf. They associate a value (x axis) with a probability (y axis). In case 'hasOrderedDomain' is true, they are sorted. Note: The function returns only a copy of the sample list.

Specified by:

getSamples in interface IProbabilityMassFunction

Returns:

the samples

setSamples

public void setSamples(List<ISample> samples)

Description copied from interface: IProbabilityMassFunction

List of samples describing the pmf. They associate a value (x axis) with a probability (y axis). In case the values can be ordered, they will be sorted. Note: The sum of all probabilities has to be one!

Specified by:

setSamples in interface IProbabilityMassFunction

Parameters:

samples - the samples to set

Throws:

ProbabilitySumNotOneException

getArithmeticMeanValue

public double getArithmeticMeanValue()
                              throws DomainNotNumbersException

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

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

drawSample

public Object drawSample()

Description copied from interface: IProbabilityMassFunction

Generates a random number of the probability function's domain, whose distribution is defined by the probability function.

Specified by:

drawSample in interface IProbabilityMassFunction

Returns:

A sample of the PMF's domain.

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

See Also:

Object.equals(java.lang.Object)

getProbabilitySum

public double getProbabilitySum()

Description copied from interface: IProbabilityFunction

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.

Specified by:

getProbabilitySum in interface IProbabilityFunction

Returns:

Sum of all probabilities in the function.

checkConstrains

public void checkConstrains()
                     throws ProbabilitySumNotOneException,
                            InvalidSampleValueException,
                            UnitNotSetException,
                            UnitNameNotSetException

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

Throws:

ProbabilitySumNotOneException

InvalidSampleValueException

UnitNotSetException

UnitNameNotSetException

getCumulativeFunction

public IProbabilityMassFunction getCumulativeFunction()

Description copied from interface: IProbabilityMassFunction

returns the cumulative probability function associated with this probability function.

Specified by:

getCumulativeFunction in interface IProbabilityMassFunction

Returns:

the computed cumulative probability function.

shiftDomain

public IProbabilityMassFunction shiftDomain(double scalar)
                                     throws DomainNotNumbersException

Description copied from interface: IProbabilityMassFunction

Shifts each value of the PMF by the given scalar (i.e., adds the given scalar to each value). If the scalar is larger than zero, the PMF gets shifted to the right, otherwise it gets shifted to the left.

Specified by:

shiftDomain in interface IProbabilityMassFunction

Returns:

Throws:

DomainNotNumbersException

stretchDomain

public IProbabilityMassFunction stretchDomain(double scalar)
                                       throws DomainNotNumbersException

Description copied from interface: IProbabilityMassFunction

Stretches the domain of the PMF by the given scalar (i.e, multiplies each value with the given scalar). If the scalar is larger than 1, the PMF gets stretched. If the scalar is between zero and 1, the PMF gets compressed.

Specified by:

stretchDomain in interface IProbabilityMassFunction

Returns:

Throws:

DomainNotNumbersException