ProfileLikelihoodCalculator.h

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// @(#)root/roostats:$Id$
// 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_ProfileLikelihoodCalculator
#define ROOSTATS_ProfileLikelihoodCalculator
 
#include "RooStats/CombinedCalculator.h"
 
#include "RooStats/LikelihoodInterval.h"
 
namespace RooStats {
 
   class LikelihoodInterval;
 
 class ProfileLikelihoodCalculator : public CombinedCalculator {
 
   public:
 
      /// Default constructor (needed for I/O)
      ProfileLikelihoodCalculator();
 
      /// Constructor from data, from a full model pdf describing both parameter of interest and nuisance parameters
      /// and from the set specifying the parameter of interest (POI).
      /// There is no need to specify the nuisance parameters since they are all other parameters of the model.
      /// When using the calculator for performing an hypothesis test one needs to provide also a snapshot (a copy)
      /// defining the null parameters and their value. There is no need to pass the alternate parameters. These
      /// will be obtained by the value maximizing the likelihood function
      ProfileLikelihoodCalculator(RooAbsData& data, RooAbsPdf& pdf, const RooArgSet& paramsOfInterest,
                                  Double_t size = 0.05, const RooArgSet* nullParams = 0 );
 
 
      /// Constructor from data and a model configuration
      /// If the ModelConfig defines a prior pdf for any of the parameters those will be included as constrained terms in the
      /// likelihood function
      ProfileLikelihoodCalculator(RooAbsData& data, ModelConfig & model, Double_t size = 0.05);
 
 
      virtual ~ProfileLikelihoodCalculator();
 
      /// Return a likelihood interval. A global fit to the likelihood is performed and
      /// the interval is constructed using the the profile likelihood ratio function of the POI
      virtual LikelihoodInterval* GetInterval() const ;
 
      /// Return the hypothesis test result obtained from the likelihood ratio of the
      /// maximum likelihood value with the null parameters fixed to their values, with respect keeping all parameters
      /// floating (global maximum likelihood value).
      virtual HypoTestResult* GetHypoTest() const;
 
 
 
   protected:
 
    // clear internal fit result
    void DoReset() const;
 
    // perform a global fit
    RooAbsReal * DoGlobalFit() const;
 
    // minimize likelihood
    static RooFitResult * DoMinimizeNLL(RooAbsReal * nll);
 
 
    mutable RooFitResult * fFitResult;  // internal  result of global fit
    mutable bool fGlobalFitDone;        // flag to control if a global fit has been done
 
 
    ClassDef(ProfileLikelihoodCalculator,2) // A concrete implementation of CombinedCalculator that uses the ProfileLikelihood ratio.
 
   };
}
#endif