class RooHistError

RooHistError is a 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.

Function Members (Methods)

public:

	RooHistError(const RooHistError&)
virtual	~RooHistError()
static TClass*	Class()
static RooAbsFunc*	createBinomialSum(Int_t n, Int_t m, Bool_t eff)
static RooAbsFunc*	createPoissonSum(Int_t n)
Bool_t	getBinomialIntervalAsym(Int_t n, Int_t m, Double_t& a1, Double_t& a2, Double_t nSigma = 1) const
Bool_t	getBinomialIntervalEff(Int_t n, Int_t m, Double_t& a1, Double_t& a2, Double_t nSigma = 1) const
Bool_t	getInterval(const RooAbsFunc* Qu, const RooAbsFunc* Ql, Double_t pointEstimate, Double_t stepSize, Double_t& lo, Double_t& hi, Double_t nSigma) const
Bool_t	getPoissonInterval(Int_t n, Double_t& mu1, Double_t& mu2, Double_t nSigma = 1) const
static const RooHistError&	instance()
virtual TClass*	IsA() const
RooHistError&	operator=(const RooHistError&)
virtual void	ShowMembers(TMemberInspector& insp, char* parent)
virtual void	Streamer(TBuffer& b)
void	StreamerNVirtual(TBuffer& b)

private:

	RooHistError()
Bool_t	getPoissonIntervalCalc(Int_t n, Double_t& mu1, Double_t& mu2, Double_t nSigma = 1) const
Double_t	seek(const RooAbsFunc& f, Double_t startAt, Double_t step, Double_t value) const

Data Members

private:

Double_t	_poissonHiLUT[1000]
Double_t	_poissonLoLUT[1000]

Class Charts

Inheritance Inherited Members Includes Libraries

Function documentation

const RooHistError & instance()

 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.

RooHistError()

 Construct our singleton object.

Bool_t getPoissonInterval(Int_t n, Double_t& mu1, Double_t& mu2, Double_t 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

Bool_t getPoissonIntervalCalc(Int_t n, Double_t& mu1, Double_t& mu2, Double_t nSigma = 1) const

 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.

Bool_t getBinomialIntervalAsym(Int_t n, Int_t m, Double_t& a1, Double_t& a2, Double_t nSigma = 1) const

 Return 'nSigma' binomial confidence interval for (n,m). The result is return in asym1 and asym2.
 If the return values is kFALSE and error occurred.

Bool_t getBinomialIntervalEff(Int_t n, Int_t m, Double_t& a1, Double_t& a2, Double_t nSigma = 1) const

 Return 'nSigma' binomial confidence interval for (n,m). The result is return in asym1 and asym2.
 If the return values is kFALSE and error occurred.

Bool_t getInterval(const RooAbsFunc* Qu, const RooAbsFunc* Ql, Double_t pointEstimate, Double_t stepSize, Double_t& lo, Double_t& hi, Double_t 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.

Double_t seek(const RooAbsFunc& f, Double_t startAt, Double_t step, Double_t value) const

 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.

RooAbsFunc * createPoissonSum(Int_t n)

 Create and return a PoissonSum function binding

RooAbsFunc * createBinomialSum(Int_t n, Int_t m, Bool_t eff)

 Create and return a BinomialSum function binding

virtual ~RooHistError()

{}

RooHistError()