ProfLike.h

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#ifndef _MdLDFFinderAG_ProfLike_h_
#define _MdLDFFinderAG_ProfLike_h_

#include "LikeFCN.h"
#include <Minuit2/MnUserParameters.h>
#include <vector>
#include <utility>
#include <utl/Trace.h>


namespace MdLDFFinderAG {

  class ProfLike {

    static const double kInitError;  // error in the initial parameters

    static const double satLikeLimit;  
    // max. value of the likelihood of a saturated window to start using the large mu approximation  

    static const double kMuPoissonApprox;  // use the Poisson approximation to the likelihood if mu is lower than this value

    public:
    ProfLike(const unsigned int, const utl::TraceUI&);
  
    double operator()(const double mu) const;

    double operator()(const double* const mup, const double* const) const { return this->operator()(*mup); } 
    // used to draw a 2 window likelihood with ROOT 

    // Get the inverse of the likelihood in the range [xmin,xmax]
    // using a numerical minimization
    double Inverse(const double y, const double xmin, const double xmax) const;

    // Get the maximum likelihood estimator
    double GetMLE() const; 

    // Get the (assymetric) error bars
    double GetErrorHigh() const;
    double GetErrorLow() const;

    // Get the low limit to the number of muons such as -logL(mu_min)=0.5
    // this method even works for a saturated likelihood!
    double GetLowLimit() const;
  
  private:
    unsigned int fNumberSegments;  // number of segments

    SegmentsOnMulti fSegmentsOnMulti;  // holds the number of segments on and their multiplicity

    unsigned int fMaxSegments;  // maximum number of segments on in a time window  

    unsigned int fMaxMultiplicity; // multiplicity of fMaxSegments

    // Methods to build the minimisation seed
    ROOT::Minuit2::MnUserParameters SetSeed(const double mu) const;
    ROOT::Minuit2::MnUserParameters SetMnUserParameters(const std::vector<double>&) const;

    double GlobalMin() const; // Calculate the global minimum of the likelihood
    double Like1(const double mu, const unsigned int k) const;   // single time window likelihood
    
    unsigned int GetTotalSegmentsOn() const;  // Calculate the number of on segments considering their multiplicity 

    // The the 1-sigma low limit to the number of muons for an unsaturated detector
    double GetLowLimitUnsaturated() const;

  };

}


#endif