RooHistError Class Reference

Singleton class used to calculate the error bars for each bin of a RooHist object.

Errors are calculated by integrating a specified area of a Poisson or Binomail error distribution.

Definition at line 25 of file RooHistError.h.

Classes
class	BinomialSumAsym
class	BinomialSumEff
class	PoissonSum

Public Member Functions
virtual	~RooHistError ()
bool	getBinomialIntervalAsym (Int_t n, Int_t m, double &a1, double &a2, double nSigma=1) const
	Return 'nSigma' binomial confidence interval for (n,m).
bool	getBinomialIntervalEff (Int_t n, Int_t m, double &a1, double &a2, double nSigma=1) const
	Return 'nSigma' binomial confidence interval for (n,m).
bool	getInterval (const RooAbsFunc *Qu, const RooAbsFunc *Ql, double pointEstimate, double stepSize, double &lo, double &hi, double nSigma) const
	Calculate a confidence interval using the cumulative functions provided.
bool	getPoissonInterval (Int_t n, double &mu1, double &mu2, double nSigma=1) const
	Return a confidence interval for the expected number of events given n observed (unweighted) events.

Static Public Member Functions
static RooAbsFunc *	createBinomialSum (Int_t n, Int_t m, bool eff)
	Create and return a BinomialSum function binding.
static RooAbsFunc *	createPoissonSum (Int_t n)
	Create and return a PoissonSum function binding.
static const RooHistError &	instance ()
	Return a reference to a singleton object that is created the first time this method is called.

Private Member Functions
	RooHistError ()
	Construct our singleton object.
bool	getPoissonIntervalCalc (Int_t n, double &mu1, double &mu2, double nSigma=1) const
	Calculate a confidence interval for the expected number of events given n observed (unweighted) events.
double	seek (const RooAbsFunc &f, double startAt, double step, double value) const
	Scan f(x)-value until it changes sign.

Private Attributes
double	_poissonHiLUT [1000]
double	_poissonLoLUT [1000]

#include <RooHistError.h>

Constructor & Destructor Documentation

~RooHistError()

virtual RooHistError::~RooHistError ( )

inlinevirtual

Definition at line 28 of file RooHistError.h.

RooHistError()

RooHistError::RooHistError ( )

private

Construct our singleton object.

Definition at line 53 of file RooHistError.cxx.

Member Function Documentation

createBinomialSum()

RooAbsFunc * RooHistError::createBinomialSum ( Int_t  n, Int_t  m, bool  eff  )

static

Create and return a BinomialSum function binding.

Definition at line 341 of file RooHistError.cxx.

createPoissonSum()

RooAbsFunc * RooHistError::createPoissonSum ( Int_t  n )

static

Create and return a PoissonSum function binding.

Definition at line 332 of file RooHistError.cxx.

getBinomialIntervalAsym()

bool RooHistError::getBinomialIntervalAsym	(	Int_t	n,
		Int_t	m,
		double &	asym1,
		double &	asym2,
		double	nSigma = 1
	)		const

Return 'nSigma' binomial confidence interval for (n,m).

The result is return in asym1 and asym2. If the return values is false and error occurred.

Definition at line 127 of file RooHistError.cxx.

getBinomialIntervalEff()

bool RooHistError::getBinomialIntervalEff	(	Int_t	n,
		Int_t	m,
		double &	asym1,
		double &	asym2,
		double	nSigma = 1
	)		const

Return 'nSigma' binomial confidence interval for (n,m).

The result is return in asym1 and asym2. If the return values is false and error occurred.

Definition at line 190 of file RooHistError.cxx.

getInterval()

bool RooHistError::getInterval	(	const RooAbsFunc *	Qu,
		const RooAbsFunc *	Ql,
		double	pointEstimate,
		double	stepSize,
		double &	lo,
		double &	hi,
		double	nSigma
	)		const

Calculate a confidence interval using the cumulative functions provided.

The interval will be "central" when both cumulative functions are provided, unless this would exclude the pointEstimate, in which case a one-sided interval pinned at the point estimate is returned instead.

Definition at line 257 of file RooHistError.cxx.

getPoissonInterval()

bool RooHistError::getPoissonInterval	(	Int_t	n,
		double &	mu1,
		double &	mu2,
		double	nSigma = 1
	)		const

Return a confidence interval for the expected number of events given n observed (unweighted) events.

The interval will contain the same probability as nSigma of a Gaussian. Uses a central interval unless this does not enclose the point estimate n (ie, for small n) in which case the interval is adjusted to start at n. This method uses a lookup table to return precalculated results for n<1000

Definition at line 73 of file RooHistError.cxx.

getPoissonIntervalCalc()

bool RooHistError::getPoissonIntervalCalc ( Int_t  n, double &  mu1, double &  mu2, double  nSigma = 1  ) const

private

Calculate a confidence interval for the expected number of events given n observed (unweighted) events.

The interval will contain the same probability as nSigma of a Gaussian. Uses a central interval unless this does not enclose the point estimate n (ie, for small n) in which case the interval is adjusted to start at n.

Definition at line 96 of file RooHistError.cxx.

instance()

const RooHistError & RooHistError::instance ( )

static

Return a reference to a singleton object that is created the first time this method is called.

Only one object will be constructed per ROOT session.

Definition at line 43 of file RooHistError.cxx.

seek()

double RooHistError::seek ( const RooAbsFunc &  f, double  startAt, double  step, double  value  ) const

private

Scan f(x)-value until it changes sign.

Start at the specified point and take constant steps of the specified size. Give up after 1000 steps.

Definition at line 309 of file RooHistError.cxx.

Member Data Documentation

_poissonHiLUT

double RooHistError::_poissonHiLUT[1000]

private

Definition at line 44 of file RooHistError.h.

_poissonLoLUT

double RooHistError::_poissonLoLUT[1000]

private

Definition at line 43 of file RooHistError.h.

Libraries for RooHistError:

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

• roofit/roofitcore/inc/RooHistError.h
• roofit/roofitcore/src/RooHistError.cxx