source: svn/trunk/external/fastjet/contribs/Nsubjettiness/Nsubjettiness.hh

// Nsubjettiness Package
//  Questions/Comments?  jthaler@jthaler.net
//
//  Copyright (c) 2011-14
//  Jesse Thaler, Ken Van Tilburg, Christopher K. Vermilion, and TJ Wilkason
//
//----------------------------------------------------------------------
// This file is part of FastJet contrib.
//
// It is free software; you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the
// Free Software Foundation; either version 2 of the License, or (at
// your option) any later version.
//
// It is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
// or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
// License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this code. If not, see <http://www.gnu.org/licenses/>.
//----------------------------------------------------------------------

#ifndef __FASTJET_CONTRIB_NSUBJETTINESS_HH__
#define __FASTJET_CONTRIB_NSUBJETTINESS_HH__

#include <fastjet/internal/base.hh>

#include "Njettiness.hh"

#include "fastjet/FunctionOfPseudoJet.hh"
#include <string>
#include <climits>


FASTJET_BEGIN_NAMESPACE      // defined in fastjet/internal/base.hh

namespace contrib {

//------------------------------------------------------------------------
/// \class Nsubjettiness
/// Nsubjettiness extends the concept of Njettiness to a jet shape, but other
/// than the set of particles considered, they are identical.  This class
/// wraps the core Njettiness code to provide the fastjet::FunctionOfPseudoJet
/// interface for convenience in larger analyses.  See NjettinessPlugin.hh for
/// definitions of tau_N and the constructor options.
class Nsubjettiness : public FunctionOfPseudoJet<double> {

public:

   // Main constructor, which takes N, axes/measure modes,
   // and up to four parameters for parameters (i.e. beta, Rcutoff, etc depending on measure)
   Nsubjettiness(int N,
                 Njettiness::AxesMode axes_mode,
                 Njettiness::MeasureMode measure_mode,
                 double para1 = NAN,
                 double para2 = NAN,
                 double para3 = NAN,
                 double para4 = NAN)
   : _njettinessFinder(axes_mode, measure_mode, para1, para2, para3, para4), _N(N) {}

   // Old constructor for backwards compatibility with v1.0,
   // where normalized_cutoff_measure was the only option
   Nsubjettiness(int N,
                 Njettiness::AxesMode axes_mode,
                 double beta,
                 double R0,
                 double Rcutoff=std::numeric_limits<double>::max())
   : _njettinessFinder(axes_mode, Njettiness::normalized_cutoff_measure, beta, R0, Rcutoff), _N(N) {}


   /// returns tau_N, measured on the constituents of this jet 
   double result(const PseudoJet& jet) const;

   /// returns components of tau_N, so that user can find individual tau values.
   TauComponents component_result(const PseudoJet& jet) const;
   
   /// returns current axes found by result() calculation
   std::vector<fastjet::PseudoJet> currentAxes() const {
      return _njettinessFinder.currentAxes();
   }

   /// returns seed axes used for onepass minimization (otherwise same as currentAxes)
   std::vector<fastjet::PseudoJet> seedAxes() const {
      return _njettinessFinder.seedAxes();
   }
   
   // To set axes for manual use
   void setAxes(std::vector<fastjet::PseudoJet> myAxes) {
      // Cross check that manual axes are being used is in Njettiness
        _njettinessFinder.setAxes(myAxes);
   }
   
   
private:
   
   mutable Njettiness _njettinessFinder; // TODO:  should muck with this so result can be const without this mutable
   int _N;

};


//------------------------------------------------------------------------
/// \class NsubjettinessRatio
// NsubjettinessRatio uses the results from Nsubjettiness to calculate the ratio
// tau_N/tau_M, where N and M are specified by the user. The ratio of different tau values
// is often used in analyses, so this class is helpful to streamline code.
class NsubjettinessRatio : public FunctionOfPseudoJet<double> {
public:

   // Main constructor.  Apart from specifying both N and M, the same options as Nsubjettiness
   NsubjettinessRatio(int N,
                      int M,
                      Njettiness::AxesMode axes_mode,
                      Njettiness::MeasureMode measure_mode,
                      double para1 = NAN,
                      double para2 = NAN,
                      double para3 = NAN,
                      double para4 = NAN)
   : _nsub_numerator(N, axes_mode, measure_mode, para1, para2, para3, para4),
   _nsub_denominator(M, axes_mode, measure_mode, para1, para2, para3, para4) {}

   //returns tau_N/tau_M based off the input jet using result function from Nsubjettiness 
   double result(const PseudoJet& jet) const;

private: 

   Nsubjettiness _nsub_numerator;
   Nsubjettiness _nsub_denominator;

};

} // namespace contrib

FASTJET_END_NAMESPACE

#endif  // __FASTJET_CONTRIB_NSUBJETTINESS_HH__