Revision cb2df8363a1266cd7134bb25bcd1f78b0107ced5 authored by Lorenzo Moneta on 10 November 2006, 14:38:23 UTC, committed by Lorenzo Moneta on 10 November 2006, 14:38:23 UTC
git-svn-id: http://root.cern.ch/svn/root/branches/v5-13-04-patches@16741 27541ba8-7e3a-0410-8455-c3a389f83636
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TFeldmanCousins.h
// @(#)root/physics:$Name: $:$Id: TFeldmanCousins.h,v 1.5 2004/02/13 14:27:00 rdm Exp $
// Author: Adrian Bevan 2001
/*************************************************************************
* Copyright (C) 1995-2004, Rene Brun and Fons Rademakers. *
* Copyright (C) 2001, Liverpool University. *
* All rights reserved. *
* *
* For the licensing terms see $ROOTSYS/LICENSE. *
* For the list of contributors see $ROOTSYS/README/CREDITS. *
*************************************************************************/
#ifndef ROOT_TFeldmanCousins
#define ROOT_TFeldmanCousins
////////////////////////////////////////////////////////////////////////////
// TFeldmanCousins
//
// class to calculate the CL upper limit using
// the Feldman-Cousins method as described in PRD V57 #7, p3873-3889
//
// The default confidence interval calvculated using this method is 90%
// This is set either by having a default the constructor, or using the
// appropriate fraction when instantiating an object of this class (e.g. 0.9)
//
// The simple extension to a gaussian resolution function bounded at zero
// has not been addressed as yet -> `time is of the essence' as they write
// on the wall of the maze in that classic game ...
//
// VARIABLES THAT CAN BE ALTERED
// -----------------------------
// => depending on your desired precision: The intial values of fMuMin,
// fMuMax, fMuStep and fNMax are those used in the PRD:
// fMuMin = 0.0
// fMuMax = 50.0
// fMuStep= 0.005
// but there is total flexibility in changing this should you desire.
//
// Author: Adrian Bevan, Liverpool University
//
// Copyright Liverpool University 2001 bevan@slac.stanford.edu
///////////////////////////////////////////////////////////////////////////
#include "TMath.h"
#include "TObject.h"
#include "TString.h"
class TFeldmanCousins : public TObject {
protected:
Double_t fCL; // confidence level as a fraction [e.g. 90% = 0.9]
Double_t fUpperLimit; // the calculated upper limit
Double_t fLowerLimit; // the calculated lower limit
Double_t fNobserved; // input number of observed events
Double_t fNbackground;// input number of background events
Double_t fMuMin; // minimum value of signal to use in calculating the tables
Double_t fMuMax; // maximum value of signal to use in calculating the tables
Double_t fMuStep; // the step in signal to use when generating tables
Int_t fNMuStep; // = (int)(fMuStep)
Int_t fNMax; // = (int)(fMuMax)
Int_t fQUICK; // take a short cut to speed up the process of generating a
// lut. This scans from Nobserved-Nbackground-fMuMin upwards
// assuming that UL > Nobserved-Nbackground.
////////////////////////////////////////////////
// calculate the poissonian probability for //
// a mean of mu+B events with a variance of N //
////////////////////////////////////////////////
Double_t Prob(Int_t N, Double_t mu, Double_t B);
////////////////////////////////////////////////
// calculate the probability table and see if //
// fNObserved is in the 100.0 * fCL % //
// interval //
////////////////////////////////////////////////
Int_t FindLimitsFromTable(Double_t mu);
public:
TFeldmanCousins(Double_t newCL=0.9, TString options = "");
virtual ~TFeldmanCousins();
////////////////////////////////////////////////
// calculate the upper limit given Nobserved //
// and Nbackground events //
// the variables fUpperLimit and fLowerLimit //
// are set before returning the upper limit //
////////////////////////////////////////////////
Double_t CalculateUpperLimit(Double_t Nobserved, Double_t Nbackground);
Double_t CalculateLowerLimit(Double_t Nobserved, Double_t Nbackground);
inline Double_t GetUpperLimit(void) const { return fUpperLimit; }
inline Double_t GetLowerLimit(void) const { return fLowerLimit; }
inline Double_t GetNobserved(void) const { return fNobserved; }
inline Double_t GetNbackground(void) const { return fNbackground; }
inline Double_t GetCL(void) const { return fCL; }
inline Double_t GetMuMin(void) const { return fMuMin; }
inline Double_t GetMuMax(void) const { return fMuMax; }
inline Double_t GetMuStep(void) const { return fMuStep; }
inline Double_t GetNMax(void) const { return fNMax; }
inline void SetNobserved(Double_t NObs) { fNobserved = NObs; }
inline void SetNbackground(Double_t Nbg) { fNbackground = Nbg; }
inline void SetCL(Double_t newCL) { fCL = newCL; }
inline void SetMuMin(Double_t newMin = 0.0) { fMuMin = newMin; }
void SetMuMax(Double_t newMax = 50.0);
void SetMuStep(Double_t newMuStep = 0.005);
ClassDef(TFeldmanCousins,1) //calculate the CL upper limit using the Feldman-Cousins method
};
#endif
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