FastJet 3.0.2
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00001 //STARTHEADER 00002 // $Id: Subtractor.hh 2577 2011-09-13 15:11:38Z salam $ 00003 // 00004 // Copyright (c) 2005-2011, Matteo Cacciari, Gavin P. Salam and Gregory Soyez 00005 // 00006 //---------------------------------------------------------------------- 00007 // This file is part of FastJet. 00008 // 00009 // FastJet is free software; you can redistribute it and/or modify 00010 // it under the terms of the GNU General Public License as published by 00011 // the Free Software Foundation; either version 2 of the License, or 00012 // (at your option) any later version. 00013 // 00014 // The algorithms that underlie FastJet have required considerable 00015 // development and are described in hep-ph/0512210. If you use 00016 // FastJet as part of work towards a scientific publication, please 00017 // include a citation to the FastJet paper. 00018 // 00019 // FastJet is distributed in the hope that it will be useful, 00020 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00021 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00022 // GNU General Public License for more details. 00023 // 00024 // You should have received a copy of the GNU General Public License 00025 // along with FastJet. If not, see <http://www.gnu.org/licenses/>. 00026 //---------------------------------------------------------------------- 00027 //ENDHEADER 00028 00029 #ifndef __FASTJET_TOOLS_SUBTRACTOR_HH__ 00030 #define __FASTJET_TOOLS_SUBTRACTOR_HH__ 00031 00032 #include "fastjet/tools/Transformer.hh" // to derive Subtractor from Transformer 00033 #include "fastjet/tools/BackgroundEstimatorBase.hh" // used as a ctor argument 00034 00035 FASTJET_BEGIN_NAMESPACE // defined in fastjet/internal/base.hh 00036 00037 00038 //---------------------------------------------------------------------- 00039 /// @ingroup tools_background 00040 /// \class Subtractor 00041 /// Class that helps perform jet background subtraction. 00042 /// 00043 /// This class derives from Transformer and makes use of a pointer to 00044 /// a BackgroundEstimatorBase object in order to determine the background 00045 /// in the vicinity of a given jet and then subtract area*background from 00046 /// the jet. It can also be initialised with a specific fixed value for the 00047 /// background pt density. 00048 /// 00049 /// \section input Input conditions 00050 /// 00051 /// The original jet must have area support (4-vector) 00052 /// 00053 /// \section output Output/interface 00054 /// 00055 /// The underlying structure of the returned, subtracted jet 00056 /// (i.e. constituents, pieces, etc.) is identical to that of the 00057 /// original jet. 00058 /// 00059 class Subtractor : public Transformer{ 00060 public: 00061 /// define a subtractor based on a BackgroundEstimator 00062 Subtractor(BackgroundEstimatorBase * bge) : 00063 _bge(bge), _rho(-1.0) {} 00064 00065 /// define a subtractor that uses a fixed value of rho, the background 00066 /// pt density per unit area (which must be positive) 00067 Subtractor(double rho); 00068 00069 /// default constructor 00070 Subtractor() : _bge(0), _rho(_invalid_rho) {} 00071 00072 /// default dtor 00073 virtual ~Subtractor(){}; 00074 00075 /// returns a jet that's subtracted 00076 /// 00077 /// \param jet the jet that is to be subtracted 00078 /// \return the subtracted jet 00079 virtual PseudoJet result(const PseudoJet & jet) const; 00080 00081 /// class description 00082 virtual std::string description() const; 00083 00084 protected: 00085 00086 /// the tool used to estimate the background 00087 /// if has to be mutable in case its underlying selector takes a reference jet 00088 mutable BackgroundEstimatorBase * _bge; 00089 /// the fixed value of rho to use if the user has selected that option 00090 double _rho; 00091 00092 /// a value of rho that is used as a default to label that the stored 00093 /// rho is not valid for subtraction. 00094 // 00095 // NB: there are two reasons for not having the value written here: 00096 // 1) that it caused problems on karnak with g++ 4.0.1 and 2) that 00097 // we anyway like -infinity as a default, and since that's a function, 00098 // that's not allowed in an include file. 00099 static const double _invalid_rho; 00100 }; 00101 00102 FASTJET_END_NAMESPACE 00103 00104 #endif // __FASTJET_TOOLS_SUBTRACTOR_HH__ 00105