TUnuranDiscrDist Class Reference

#include <TUnuranDiscrDist.h>

Inheritance diagram for TUnuranDiscrDist:


Public Member Functions
	TUnuranDiscrDist (const ROOT::Math::IGenFunction &func, bool copyFunc=false)
	TUnuranDiscrDist (TF1 *func)
template<class Iterator>
	TUnuranDiscrDist (Iterator begin, Iterator end)
virtual	~TUnuranDiscrDist ()
	TUnuranDiscrDist (const TUnuranDiscrDist &)
TUnuranDiscrDist &	operator= (const TUnuranDiscrDist &rhs)
virtual TUnuranDiscrDist *	Clone () const
void	SetCdf (const ROOT::Math::IGenFunction &cdf)
void	SetCdf (TF1 *cdf)
void	SetDomain (int xmin, int xmax)
void	SetMode (int mode)
void	SetProbSum (double sum)
bool	GetDomain (int &xmin, int &xmax) const
int	Mode () const
double	ProbSum () const
bool	HasMode () const
bool	HasProbSum () const
bool	HasCdf () const
const std::vector< double > &	ProbVec () const
double	Pmf (int x) const
double	Cdf (int x) const
Private Attributes
std::vector< double >	fPVec
std::vector< double >	fPVecSum
const ROOT::Math::IGenFunction *	fPmf
const ROOT::Math::IGenFunction *	fCdf
int	fXmin
int	fXmax
int	fMode
double	fSum
bool	fHasDomain
bool	fHasMode
bool	fHasSum
bool	fOwnFunc

Detailed Description

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 53 of file TUnuranDiscrDist.h.

Constructor & Destructor Documentation

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.

References ROOT::Math::IBaseFunctionOneDim::Clone(), fOwnFunc, and fPmf.

Referenced by Clone().

TUnuranDiscrDist::TUnuranDiscrDist ( TF1 * func )

Constructor from a TF1 objects specifying the pdf

Definition at line 43 of file TUnuranDiscrDist.cxx.

template<class Iterator>

TUnuranDiscrDist::TUnuranDiscrDist	(	Iterator *	begin,
		Iterator *	end
	)			`[inline]`

Constructor from a vector of probability

Definition at line 71 of file TUnuranDiscrDist.h.

TUnuranDiscrDist::~TUnuranDiscrDist ( ) [virtual]

Destructor

Definition at line 96 of file TUnuranDiscrDist.cxx.

References fCdf, fOwnFunc, and fPmf.

TUnuranDiscrDist::TUnuranDiscrDist ( const TUnuranDiscrDist & )

Copy constructor

Definition at line 59 of file TUnuranDiscrDist.cxx.

References operator=().

Member Function Documentation

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

Assignment operator

Definition at line 68 of file TUnuranDiscrDist.cxx.

References ROOT::Math::IBaseFunctionOneDim::Clone(), fCdf, fHasDomain, fHasMode, fHasSum, fMode, fOwnFunc, fPmf, fPVec, fPVecSum, fSum, fXmax, and fXmin.

Referenced by TUnuranDiscrDist().

virtual TUnuranDiscrDist* TUnuranDiscrDist::Clone ( ) const [inline, virtual]

Clone (required by base class)

Implements TUnuranBaseDist.

Definition at line 103 of file TUnuranDiscrDist.h.

References TUnuranDiscrDist().

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.

References cdf(), fCdf, and fOwnFunc.

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.

References cdf(), ROOT::Math::IBaseFunctionOneDim::Clone(), fCdf, fOwnFunc, and fPmf.

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 122 of file TUnuranDiscrDist.h.

References fHasDomain, fXmax, and fXmin.

void TUnuranDiscrDist::SetMode ( int mode ) [inline]

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

Definition at line 135 of file TUnuranDiscrDist.h.

References fHasMode, and fMode.

Referenced by testDiscDistr(), and testPoisson().

void TUnuranDiscrDist::SetProbSum ( double sum ) [inline]

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

Definition at line 140 of file TUnuranDiscrDist.h.

References fHasSum, and fSum.

Referenced by testDiscDistr(), and testPoisson().

bool TUnuranDiscrDist::GetDomain	(	int &	xmin,
		int &	xmax
	)			const `[inline]`

check if distribution has domain and return in case its domain

Definition at line 145 of file TUnuranDiscrDist.h.

References fHasDomain, fXmax, and fXmin.

int TUnuranDiscrDist::Mode ( ) const [inline]

get the mode (x location of function maximum)

Definition at line 154 of file TUnuranDiscrDist.h.

References fMode.

double TUnuranDiscrDist::ProbSum ( ) const [inline]

return area of the pdf

Definition at line 159 of file TUnuranDiscrDist.h.

References fSum.

bool TUnuranDiscrDist::HasMode ( ) const [inline]

flag to control if distribution provides the mode

Definition at line 165 of file TUnuranDiscrDist.h.

References fHasMode.

bool TUnuranDiscrDist::HasProbSum ( ) const [inline]

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

Definition at line 171 of file TUnuranDiscrDist.h.

References fHasSum.

bool TUnuranDiscrDist::HasCdf ( ) const [inline]

flag to control if distribution provides also a Cdf

Definition at line 176 of file TUnuranDiscrDist.h.

References fCdf.

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 184 of file TUnuranDiscrDist.h.

References fPVec.

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.

References double, fPmf, and fPVec.

Referenced by Cdf().

double TUnuranDiscrDist::Cdf ( int x ) const

evaluate the integral (cdf) on the given domain

Definition at line 131 of file TUnuranDiscrDist.cxx.

References double, fCdf, fHasDomain, fPVecSum, fXmin, i, Pmf(), and x0.