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ROOT 6.07/09 Reference Guide |
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 55 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. More... | |
TUnuranDiscrDist (TF1 *func) | |
Constructor from a TF1 objects specifying the pdf. More... | |
template<class Iterator > | |
TUnuranDiscrDist (Iterator *begin, Iterator *end) | |
Constructor from a vector of probability. More... | |
TUnuranDiscrDist (const TUnuranDiscrDist &) | |
Copy constructor. More... | |
virtual | ~TUnuranDiscrDist () |
Destructor. More... | |
double | Cdf (int x) const |
evaluate the integral (cdf) on the given domain More... | |
virtual TUnuranDiscrDist * | Clone () const |
Clone (required by base class) More... | |
bool | GetDomain (int &xmin, int &xmax) const |
check if distribution has domain and return in case its domain More... | |
bool | HasCdf () const |
flag to control if distribution provides also a Cdf More... | |
bool | HasMode () const |
flag to control if distribution provides the mode More... | |
bool | HasProbSum () const |
flag to control if distribution provides the total area of the probability function More... | |
int | Mode () const |
get the mode (x location of function maximum) More... | |
TUnuranDiscrDist & | operator= (const TUnuranDiscrDist &rhs) |
Assignment operator. More... | |
double | Pmf (int x) const |
evaluate the distribution (probability mesh function) at the integer value x. More... | |
double | ProbSum () const |
return area of the pdf More... | |
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. More... | |
void | SetCdf (const ROOT::Math::IGenFunction &cdf) |
set cdf distribution from a generic function interface. More... | |
void | SetCdf (TF1 *cdf) |
set cdf distribution from a TF1 pointer. More... | |
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. More... | |
void | SetMode (int mode) |
set the mode of the distribution (location of maximum probability) More... | |
void | SetProbSum (double sum) |
set the value of the sum of the probabilities in the given domain More... | |
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virtual | ~TUnuranBaseDist () |
Destructor (no operations) More... | |
Private Attributes | |
const ROOT::Math::IGenFunction * | fCdf |
bool | fHasDomain |
bool | fHasMode |
bool | fHasSum |
int | fMode |
bool | fOwnFunc |
const ROOT::Math::IGenFunction * | fPmf |
std::vector< double > | fPVec |
std::vector< double > | fPVecSum |
double | fSum |
int | fXmax |
int | fXmin |
#include <TUnuranDiscrDist.h>
TUnuranDiscrDist::TUnuranDiscrDist | ( | const ROOT::Math::IGenFunction & | func, |
bool | copyFunc = false |
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Constructor from a generic function object specifying the pdf.
Definition at line 23 of file TUnuranDiscrDist.cxx.
TUnuranDiscrDist::TUnuranDiscrDist | ( | TF1 * | func | ) |
Constructor from a TF1 objects specifying the pdf.
Definition at line 43 of file TUnuranDiscrDist.cxx.
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Constructor from a vector of probability.
Definition at line 73 of file TUnuranDiscrDist.h.
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Destructor.
Definition at line 96 of file TUnuranDiscrDist.cxx.
TUnuranDiscrDist::TUnuranDiscrDist | ( | const TUnuranDiscrDist & | rhs | ) |
Copy constructor.
Definition at line 59 of file TUnuranDiscrDist.cxx.
double TUnuranDiscrDist::Cdf | ( | int | x | ) | const |
evaluate the integral (cdf) on the given domain
Definition at line 131 of file TUnuranDiscrDist.cxx.
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Clone (required by base class)
Implements TUnuranBaseDist.
Definition at line 105 of file TUnuranDiscrDist.h.
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check if distribution has domain and return in case its domain
Definition at line 147 of file TUnuranDiscrDist.h.
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flag to control if distribution provides also a Cdf
Definition at line 178 of file TUnuranDiscrDist.h.
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flag to control if distribution provides the mode
Definition at line 167 of file TUnuranDiscrDist.h.
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flag to control if distribution provides the total area of the probability function
Definition at line 173 of file TUnuranDiscrDist.h.
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get the mode (x location of function maximum)
Definition at line 156 of file TUnuranDiscrDist.h.
TUnuranDiscrDist & TUnuranDiscrDist::operator= | ( | const TUnuranDiscrDist & | rhs | ) |
Assignment operator.
Definition at line 68 of file TUnuranDiscrDist.cxx.
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.
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return area of the pdf
Definition at line 161 of file TUnuranDiscrDist.h.
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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 186 of file TUnuranDiscrDist.h.
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.
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.
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Set the distribution domain, by default the domain is [0,INT_MAX] If xmin >= xmax a domain is removed.
Definition at line 124 of file TUnuranDiscrDist.h.
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set the mode of the distribution (location of maximum probability)
Definition at line 137 of file TUnuranDiscrDist.h.
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set the value of the sum of the probabilities in the given domain
Definition at line 142 of file TUnuranDiscrDist.h.
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Definition at line 209 of file TUnuranDiscrDist.h.
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Definition at line 215 of file TUnuranDiscrDist.h.
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Definition at line 216 of file TUnuranDiscrDist.h.
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Definition at line 217 of file TUnuranDiscrDist.h.
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Definition at line 212 of file TUnuranDiscrDist.h.
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Definition at line 218 of file TUnuranDiscrDist.h.
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Definition at line 208 of file TUnuranDiscrDist.h.
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Definition at line 206 of file TUnuranDiscrDist.h.
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Definition at line 207 of file TUnuranDiscrDist.h.
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Definition at line 213 of file TUnuranDiscrDist.h.
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Definition at line 211 of file TUnuranDiscrDist.h.
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Definition at line 210 of file TUnuranDiscrDist.h.