// @(#)root/roostats:$Id: HypoTestInverterResult.h 36230 2010-10-09 20:21:02Z wouter $
// 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 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();

    // 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 a pointer to the i^th result object
    HypoTestResult* GetResult( int index ) const ;   

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

    // 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();

  private:

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

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

  protected:

    bool fUseCLs; 
    bool fInterpolateLowerLimit;
    bool fInterpolateUpperLimit;

    std::vector<double> fXValues;

    TList fYObjects;

    friend class HypoTestInverter;

    ClassDef(HypoTestInverterResult,1)  // HypoTestInverterResult class      
  };
}

#endif