TUnuranDiscrDist class for one dimensional discrete distribution.

It is used by TUnuran to generate integer random numbers according to this distribution via TUnuran::SampleDiscr().

The class can be constructed from a one-dimensional function (TF1 pointer) representing the discrete distribution (probability mesh function) (for example a TF1("f","TMath::PoissonI(x,[0])") ) or from a vector of probability, used by passing an iterator specifying the begin and the end of the vector. In the latter case the domain of the distribution will be defined by the vector, while in the first case is by default (0,+inf). a Method to set the domain of the distribution ( SetDomain ) is provided and it defines the range of the generated random numbers.

The derivatives of the pdf which are used by some UNURAN methods are estimated numerically in the Derivative() method. Some extra information (like distribution mode, cdf function, probability sum, etc..) can be set as well otherwise will be estimated internally if required.

Definition at line 51 of file TUnuranDiscrDist.h.

Public Member Functions
	TUnuranDiscrDist (const ROOT::Math::IGenFunction &func, bool copyFunc=false)
	Constructor from a generic function object specifying the pdf.

	TUnuranDiscrDist (const TUnuranDiscrDist &)
	Copy constructor.

template<class Iterator >
	TUnuranDiscrDist (Iterator begin, Iterator end)
	Constructor from a vector of probability.

	TUnuranDiscrDist (TF1 *func)
	Constructor from a TF1 objects specifying the pdf.

	~TUnuranDiscrDist () override
	Destructor.

double	Cdf (int x) const
	evaluate the integral (cdf) on the given domain

TUnuranDiscrDist *	Clone () const override
	Clone (required by base class)

bool	GetDomain (int &xmin, int &xmax) const
	check if distribution has domain and return in case its domain

bool	HasCdf () const
	flag to control if distribution provides also a Cdf

bool	HasMode () const
	flag to control if distribution provides the mode

bool	HasProbSum () const
	flag to control if distribution provides the total area of the probability function

TClass *	IsA () const override

int	Mode () const
	get the mode (x location of function maximum)

TUnuranDiscrDist &	operator= (const TUnuranDiscrDist &rhs)
	Assignment operator.

double	Pmf (int x) const
	evaluate the distribution (probability mesh function) at the integer value x.

double	ProbSum () const
	return area of the pdf

const std::vector< double > &	ProbVec () const
	retrieve a reference to the vector of the probabilities : Prob(i) If the distribution is defined from a function (i.e.

void	SetCdf (const ROOT::Math::IGenFunction &cdf)
	set cdf distribution from a generic function interface.

void	SetCdf (TF1 *cdf)
	set cdf distribution from a TF1 pointer.

void	SetDomain (int xmin, int xmax)
	Set the distribution domain, by default the domain is [0,INT_MAX] If xmin >= xmax a domain is removed.

void	SetMode (int mode)
	set the mode of the distribution (location of maximum probability)

void	SetProbSum (double sum)
	set the value of the sum of the probabilities in the given domain

void	Streamer (TBuffer &) override

void	StreamerNVirtual (TBuffer &ClassDef_StreamerNVirtual_b)

Public Member Functions inherited from TUnuranBaseDist
virtual	~TUnuranBaseDist ()
	Destructor (no operations)

void	StreamerNVirtual (TBuffer &ClassDef_StreamerNVirtual_b)

Static Public Member Functions
static TClass *	Class ()

static const char *	Class_Name ()

static constexpr Version_t	Class_Version ()

static const char *	DeclFileName ()

Static Public Member Functions inherited from TUnuranBaseDist
static TClass *	Class ()

static const char *	Class_Name ()

static constexpr Version_t	Class_Version ()

static const char *	DeclFileName ()

Private Attributes
const ROOT::Math::IGenFunction *	fCdf
	pointer to the cumulative distribution function

bool	fHasDomain
	flag to control if distribution has a defined domain (otherwise is [0,INT_MAX])

bool	fHasMode
	flag to control if distribution has a pre-computed mode

bool	fHasSum
	flag to control if distribution has a pre-computed sum of the probabilities

int	fMode
	mode of the distribution

bool	fOwnFunc
	flag to control if distribution owns the function pointers

const ROOT::Math::IGenFunction *	fPmf
	pointer to a function calculating the probability

std::vector< double >	fPVec
	Vector of the probabilities.

std::vector< double >	fPVecSum
	Vector of the sum of the probabilities.

double	fSum
	total sum of the probabilities in the given domain

int	fXmax
	upper value of the domain

int	fXmin
	lower value of the domain

#include <TUnuranDiscrDist.h>

Inheritance diagram for TUnuranDiscrDist:

[legend]

Constructor & Destructor Documentation

◆ TUnuranDiscrDist() [1/4]

TUnuranDiscrDist::TUnuranDiscrDist	(	const ROOT::Math::IGenFunction &	func,
		bool	copyFunc = `false`
	)

Constructor from a generic function object specifying the pdf.

Definition at line 23 of file TUnuranDiscrDist.cxx.

◆ TUnuranDiscrDist() [2/4]

TUnuranDiscrDist::TUnuranDiscrDist ( TF1 * func )

Constructor from a TF1 objects specifying the pdf.

Definition at line 43 of file TUnuranDiscrDist.cxx.

◆ TUnuranDiscrDist() [3/4]

template<class Iterator >

TUnuranDiscrDist::TUnuranDiscrDist	(	Iterator *	begin,
		Iterator *	end
	)

inline

Constructor from a vector of probability.

Definition at line 69 of file TUnuranDiscrDist.h.

◆ ~TUnuranDiscrDist()

TUnuranDiscrDist::~TUnuranDiscrDist ( )

override

Destructor.

Definition at line 96 of file TUnuranDiscrDist.cxx.

◆ TUnuranDiscrDist() [4/4]

TUnuranDiscrDist::TUnuranDiscrDist ( const TUnuranDiscrDist & rhs )

Copy constructor.

Definition at line 59 of file TUnuranDiscrDist.cxx.

Member Function Documentation

◆ Cdf()

double TUnuranDiscrDist::Cdf ( int x ) const

evaluate the integral (cdf) on the given domain

Definition at line 131 of file TUnuranDiscrDist.cxx.

◆ Class()

static TClass * TUnuranDiscrDist::Class ( )

static

Returns: TClass describing this class

◆ Class_Name()

static const char * TUnuranDiscrDist::Class_Name ( )

static

Returns: Name of this class

◆ Class_Version()

static constexpr Version_t TUnuranDiscrDist::Class_Version ( )

inlinestaticconstexpr

Returns: Version of this class

Definition at line 216 of file TUnuranDiscrDist.h.

◆ Clone()

TUnuranDiscrDist * TUnuranDiscrDist::Clone ( ) const

inlineoverridevirtual

Clone (required by base class)

Implements TUnuranBaseDist.

Definition at line 101 of file TUnuranDiscrDist.h.

◆ DeclFileName()

static const char * TUnuranDiscrDist::DeclFileName ( )

inlinestatic

Returns: Name of the file containing the class declaration

Definition at line 216 of file TUnuranDiscrDist.h.

◆ GetDomain()

bool TUnuranDiscrDist::GetDomain	(	int &	xmin,
		int &	xmax
	)		const

inline

check if distribution has domain and return in case its domain

Definition at line 143 of file TUnuranDiscrDist.h.

◆ HasCdf()

bool TUnuranDiscrDist::HasCdf ( ) const

inline

flag to control if distribution provides also a Cdf

Definition at line 174 of file TUnuranDiscrDist.h.

◆ HasMode()

bool TUnuranDiscrDist::HasMode ( ) const

inline

flag to control if distribution provides the mode

Definition at line 163 of file TUnuranDiscrDist.h.

◆ HasProbSum()

bool TUnuranDiscrDist::HasProbSum ( ) const

inline

flag to control if distribution provides the total area of the probability function

Definition at line 169 of file TUnuranDiscrDist.h.

◆ IsA()

TClass * TUnuranDiscrDist::IsA ( ) const

inlineoverridevirtual

Returns: TClass describing current object

Reimplemented from TUnuranBaseDist.

Definition at line 216 of file TUnuranDiscrDist.h.

◆ Mode()

int TUnuranDiscrDist::Mode ( ) const

inline

get the mode (x location of function maximum)

Definition at line 152 of file TUnuranDiscrDist.h.

◆ operator=()

TUnuranDiscrDist & TUnuranDiscrDist::operator= ( const TUnuranDiscrDist & rhs )

Assignment operator.

Definition at line 68 of file TUnuranDiscrDist.cxx.

◆ Pmf()

double TUnuranDiscrDist::Pmf ( int x ) const

evaluate the distribution (probability mesh function) at the integer value x.

Used internally by UnuRan For integer values outside the domain the function must return 0.0

Definition at line 122 of file TUnuranDiscrDist.cxx.

◆ ProbSum()

double TUnuranDiscrDist::ProbSum ( ) const

inline

return area of the pdf

Definition at line 157 of file TUnuranDiscrDist.h.

◆ ProbVec()

const std::vector< double > & TUnuranDiscrDist::ProbVec ( ) const

inline

retrieve a reference to the vector of the probabilities : Prob(i) If the distribution is defined from a function (i.e.

for distribution with undefined domain) the vector is empty.

Definition at line 182 of file TUnuranDiscrDist.h.

◆ SetCdf() [1/2]

void TUnuranDiscrDist::SetCdf ( const ROOT::Math::IGenFunction & cdf )

set cdf distribution from a generic function interface.

If a method requires it and is not set it is estimated numerically

Definition at line 104 of file TUnuranDiscrDist.cxx.

◆ SetCdf() [2/2]

void TUnuranDiscrDist::SetCdf ( TF1 * cdf )

set cdf distribution from a TF1 pointer.

If a method requires it and is not set it is estimated numerically

Definition at line 109 of file TUnuranDiscrDist.cxx.

◆ SetDomain()

void TUnuranDiscrDist::SetDomain	(	int	xmin,
		int	xmax
	)

inline

Set the distribution domain, by default the domain is [0,INT_MAX] If xmin >= xmax a domain is removed.

Definition at line 120 of file TUnuranDiscrDist.h.

◆ SetMode()

void TUnuranDiscrDist::SetMode ( int mode )

inline

set the mode of the distribution (location of maximum probability)

Definition at line 133 of file TUnuranDiscrDist.h.

◆ SetProbSum()

void TUnuranDiscrDist::SetProbSum ( double sum )

inline

set the value of the sum of the probabilities in the given domain

Definition at line 138 of file TUnuranDiscrDist.h.

◆ Streamer()

void TUnuranDiscrDist::Streamer ( TBuffer & )

overridevirtual

Reimplemented from TUnuranBaseDist.

◆ StreamerNVirtual()

void TUnuranDiscrDist::StreamerNVirtual ( TBuffer & ClassDef_StreamerNVirtual_b )

inline

Definition at line 216 of file TUnuranDiscrDist.h.

Member Data Documentation

◆ fCdf

const ROOT::Math::IGenFunction* TUnuranDiscrDist::fCdf

private

pointer to the cumulative distribution function

Definition at line 205 of file TUnuranDiscrDist.h.

◆ fHasDomain

bool TUnuranDiscrDist::fHasDomain

private

flag to control if distribution has a defined domain (otherwise is [0,INT_MAX])

Definition at line 211 of file TUnuranDiscrDist.h.

◆ fHasMode

bool TUnuranDiscrDist::fHasMode

private

flag to control if distribution has a pre-computed mode

Definition at line 212 of file TUnuranDiscrDist.h.

◆ fHasSum

bool TUnuranDiscrDist::fHasSum

private

flag to control if distribution has a pre-computed sum of the probabilities

Definition at line 213 of file TUnuranDiscrDist.h.

◆ fMode

int TUnuranDiscrDist::fMode

private

mode of the distribution

Definition at line 208 of file TUnuranDiscrDist.h.

◆ fOwnFunc

bool TUnuranDiscrDist::fOwnFunc

private

flag to control if distribution owns the function pointers

Definition at line 214 of file TUnuranDiscrDist.h.

◆ fPmf

const ROOT::Math::IGenFunction* TUnuranDiscrDist::fPmf

private

pointer to a function calculating the probability

Definition at line 204 of file TUnuranDiscrDist.h.

◆ fPVec

std::vector<double> TUnuranDiscrDist::fPVec

private

Vector of the probabilities.

Definition at line 202 of file TUnuranDiscrDist.h.

◆ fPVecSum

std::vector<double> TUnuranDiscrDist::fPVecSum

mutableprivate

Vector of the sum of the probabilities.

Definition at line 203 of file TUnuranDiscrDist.h.

◆ fSum

double TUnuranDiscrDist::fSum

private

total sum of the probabilities in the given domain

Definition at line 209 of file TUnuranDiscrDist.h.

◆ fXmax

int TUnuranDiscrDist::fXmax

private

upper value of the domain

Definition at line 207 of file TUnuranDiscrDist.h.

◆ fXmin

int TUnuranDiscrDist::fXmin

private

lower value of the domain

Definition at line 206 of file TUnuranDiscrDist.h.

Libraries for TUnuranDiscrDist:

[legend]

The documentation for this class was generated from the following files:

math/unuran/inc/TUnuranDiscrDist.h
math/unuran/src/TUnuranDiscrDist.cxx

Public Member Functions

Static Public Member Functions

Private Attributes

Constructor & Destructor Documentation

◆ TUnuranDiscrDist() [1/4]

◆ TUnuranDiscrDist() [2/4]

◆ TUnuranDiscrDist() [3/4]

◆ ~TUnuranDiscrDist()

◆ TUnuranDiscrDist() [4/4]

Member Function Documentation

◆ Cdf()

◆ Class()

◆ Class_Name()

◆ Class_Version()

◆ Clone()

◆ DeclFileName()

◆ GetDomain()

◆ HasCdf()

◆ HasMode()

◆ HasProbSum()

◆ IsA()

◆ Mode()

◆ operator=()

◆ Pmf()

◆ ProbSum()

◆ ProbVec()

◆ SetCdf() [1/2]

◆ SetCdf() [2/2]

◆ SetDomain()

◆ SetMode()

◆ SetProbSum()

◆ Streamer()

◆ StreamerNVirtual()

Member Data Documentation

◆ fCdf

◆ fHasDomain

◆ fHasMode

◆ fHasSum

◆ fMode

◆ fOwnFunc

◆ fPmf

◆ fPVec

◆ fPVecSum

◆ fSum

◆ fXmax

◆ fXmin