// @(#)root/roostats:$Id: HypoTestInverterResult.h 40023 2011-06-27 16:58:44Z moneta $
// Author: Kyle Cranmer, Lorenzo Moneta, Gregory Schott, Wouter Verkerke
/*************************************************************************
 * Copyright (C) 1995-2008, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/

#ifndef ROOSTATS_HypoTestInverterResult
#define ROOSTATS_HypoTestInverterResult



#ifndef ROOSTATS_SimpleInterval
#include "RooStats/SimpleInterval.h"
#endif

#include "RooStats/HypoTestResult.h"

class RooRealVar;

namespace RooStats {

class SamplingDistribution;

class HypoTestInverterResult : public SimpleInterval {

public:

   // default constructor
   explicit HypoTestInverterResult(const char* name = 0);

   // constructor
   HypoTestInverterResult( const char* name, 
                           const RooRealVar& scannedVariable,
                           double cl ) ;

   // destructor
   virtual ~HypoTestInverterResult();

   // merge with the content of another HypoTestInverterResult object
   bool Add( const HypoTestInverterResult& otherResult );


   // function to return the value of the parameter of interest for the i^th entry in the results
   double GetXValue( int index ) const ;

   // function to return the value of the confidence level for the i^th entry in the results
   double GetYValue( int index ) const ;

   // function to return the estimated error on the value of the confidence level for the i^th entry in the results
   double GetYError( int index ) const ;

   // return the observed CLsplusb value  for the i-th entry
   double CLsplusb( int index) const; 
 
   // return the observed CLb value  for the i-th entry
   double CLb( int index) const; 

   // return the observed CLb value  for the i-th entry
   double CLs( int index) const; 

   // return the observed CLsplusb value  for the i-th entry
   double CLsplusbError( int index) const; 
 
   // return the observed CLb value  for the i-th entry
   double CLbError( int index) const; 

   // return the observed CLb value  for the i-th entry
   double CLsError( int index) const; 
   
   // return a pointer to the i^th result object
   HypoTestResult* GetResult( int index ) const ;   

   double GetLastYValue( ) const  { return GetYValue(  fXValues.size()-1); }

   double GetLastXValue( ) const  { return GetXValue(  fXValues.size()-1); }

   double GetLastYError( ) const  { return GetYError(  fXValues.size()-1); }

   HypoTestResult * GetLastResult( ) const  { return GetResult(  fXValues.size()-1); }

   // number of entries in the results array
   int ArraySize() const { return fXValues.size(); };

   int FindIndex(double xvalue) const;

   // set the size of the test (rate of Type I error) (eg. 0.05 for a 95% Confidence Interval)
   virtual void SetTestSize( Double_t size ) { fConfidenceLevel = 1.-size; }

   // set the confidence level for the interval (eg. 0.95 for a 95% Confidence Interval)
   virtual void SetConfidenceLevel( Double_t cl ) { fConfidenceLevel = cl; }

   // flag to switch between using CLsb (default) or CLs as confidence level
   void UseCLs( bool on = true ) { fUseCLs = on; }  

   // lower and upper bound of the confidence interval (to get upper/lower limits, multiply the size( = 1-confidence level ) by 2
   Double_t LowerLimit();
   Double_t UpperLimit();

   // rough estimation of the error on the computed bound of the confidence interval 
   // Estimate of lower limit error
   //function evaluates only a rought error on the lower limit. Be careful when using this estimation
   Double_t LowerLimitEstimatedError();

   // Estimate of lower limit error
   //function evaluates only a rought error on the lower limit. Be careful when using this estimation
   Double_t UpperLimitEstimatedError();

   // return expected distribution of p-values (Cls or Clsplusb)
   
   SamplingDistribution * GetExpectedPValueDist(int index) const; 

   SamplingDistribution * GetBackgroundTestStatDist(int index ) const; 

   SamplingDistribution * GetSignalAndBackgroundTestStatDist(int index) const; 

   // same in terms of alt and null
   SamplingDistribution * GetNullTestStatDist(int index) const { 
      return  GetSignalAndBackgroundTestStatDist(index);
   }
   SamplingDistribution * GetAltTestStatDist(int index) const { 
      return  GetBackgroundTestStatDist(index);
   }

   // get expected lower limit distributions
   // implemented using interpolation
   SamplingDistribution* GetLowerLimitDistribution( ) const { return GetLimitDistribution(true); }

   // get expected upper limit distributions
   // implemented using interpolation
   SamplingDistribution* GetUpperLimitDistribution( ) const { return GetLimitDistribution(false); }

   // get Limit value correspnding at the desired nsigma level (0) is median -1 sigma is 1 sigma
   double GetExpectedLowerLimit(double nsig = 0) const ; 

   // get Limit value correspnding at the desired nsigma level (0) is median -1 sigma is 1 sigma
   double GetExpectedUpperLimit(double nsig = 0) const ; 


   double FindInterpolatedLimit(double target, bool lowSearch = false, double xmin=1, double xmax=0);

   enum InterpolOption_t { kLinear, kSpline };

   // set the interpolation option, linear (kLinear ) or spline  (kSpline)
   void SetInterpolationOption( InterpolOption_t opt) { fInterpolOption = opt; }
   
   InterpolOption_t GetInterpolationOption() const { return fInterpolOption; }

private:


   double CalculateEstimatedError(double target);
   int FindClosestPointIndex(double target);

   SamplingDistribution* GetLimitDistribution(bool lower ) const;

   double GetExpectedLimit(double nsig, bool lower ) const ; 

   double GetGraphX(const TGraph & g, double y0, bool lowSearch = false, double xmin=1, double xmax=0) const;

 
protected:

   
   bool fUseCLs; 
   bool fInterpolateLowerLimit;
   bool fInterpolateUpperLimit;
   bool fFittedLowerLimit;
   bool fFittedUpperLimit;
   InterpolOption_t fInterpolOption;  // interpolatation option (linear or spline)

   double fLowerLimitError;
   double fUpperLimitError;

   std::vector<double> fXValues;

   TList fYObjects;       // list of HypoTestResult for each point
   TList fExpPValues;     // list of expected sampling distribution for each point

   friend class HypoTestInverter;
   friend class HypoTestInverterPlot;
   friend class HypoTestInverterOriginal;

   ClassDef(HypoTestInverterResult,3)  // HypoTestInverterResult class      
};
}

#endif