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 // fjcore -- extracted from FastJet v3.4.0 (http://fastjet.fr)
 //
 // fjcore constitutes a digest of the main FastJet functionality.
 // The files fjcore.hh and fjcore.cc are meant to provide easy access to these 
 // core functions, in the form of single files and without the need of a full 
 // FastJet installation:
 //
 //     g++ main.cc fjcore.cc
 // 
 // with main.cc including fjcore.hh.
 //
 // A fortran interface, fjcorefortran.cc, is also provided. See the example 
 // and the Makefile for instructions.
 //
 // The results are expected to be identical to those obtained by linking to
 // the full FastJet distribution.
 //
 // NOTE THAT, IN ORDER TO MAKE IT POSSIBLE FOR FJCORE AND THE FULL FASTJET
 // TO COEXIST, THE FORMER USES THE "fjcore" NAMESPACE INSTEAD OF "fastjet". 
 //
 // In particular, fjcore provides:
 //
 //   - access to all native pp and ee algorithms, kt, anti-kt, C/A.
 //     For C/A, the NlnN method is available, while anti-kt and kt
 //     are limited to the N^2 one (still the fastest for N < 100k particles)
 //   - access to selectors, for implementing cuts and selections
 //   - access to all functionalities related to pseudojets (e.g. a jet's
 //     structure or user-defined information)
 //
 // Instead, it does NOT provide:
 //
 //   - jet areas functionality
 //   - background estimation
 //   - access to other algorithms via plugins
 //   - interface to CGAL
 //   - fastjet tools, e.g. filters, taggers
 //
 // If these functionalities are needed, the full FastJet installation must be
 // used. The code will be fully compatible, with the sole replacement of the
 // header files and of the fjcore namespace with the fastjet one.
 //
 // fjcore.hh and fjcore.cc are not meant to be human-readable.
 // For documentation, see the full FastJet manual and doxygen at http://fastjet.fr
 //
 // Like FastJet, fjcore is released under the terms of the GNU General Public
 // License version 2 (GPLv2). If you use this code as part of work towards a
 // scientific publication, whether directly or contained within another program
 // (e.g. Delphes, MadGraph, SpartyJet, Rivet, LHC collaboration software frameworks, 
 // etc.), you should include a citation to
 // 
 //   EPJC72(2012)1896 [arXiv:1111.6097] (FastJet User Manual)
 //   and, optionally, Phys.Lett.B641 (2006) 57 [arXiv:hep-ph/0512210]
 //
 //FJSTARTHEADER
 // $Id$
 //
 // Copyright (c) 2005-2021, Matteo Cacciari, Gavin P. Salam and Gregory Soyez
 //
 //----------------------------------------------------------------------
 // This file is part of FastJet (fjcore).
 //
 //  FastJet 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.
 //
 //  The algorithms that underlie FastJet have required considerable
 //  development. They are described in the original FastJet paper,
 //  hep-ph/0512210 and in the manual, arXiv:1111.6097. If you use
 //  FastJet as part of work towards a scientific publication, please
 //  quote the version you use and include a citation to the manual and
 //  optionally also to hep-ph/0512210.
 //
 //  FastJet 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 FastJet. If not, see <http://www.gnu.org/licenses/>.
 //----------------------------------------------------------------------
 //FJENDHEADER
 #ifndef __FJCORE_HH__
 #define __FJCORE_HH__
 #define __FJCORE__   // remove all the non-core code (a safekeeper)
 #define __FJCORE_DROP_CGAL    // disable CGAL support
 #ifndef _INCLUDE_FJCORE_CONFIG_AUTO_H
 #define _INCLUDE_FJCORE_CONFIG_AUTO_H 1
 #ifndef FJCORE_HAVE_AUTO_PTR_INTERFACE 
 #endif
 #ifndef FJCORE_HAVE_CXX14_DEPRECATED 
 #endif
 #ifndef FJCORE_HAVE_DLFCN_H 
 # define FJCORE_HAVE_DLFCN_H  1 
 #endif
 #ifndef FJCORE_HAVE_EXECINFO_H 
 #endif
 #ifndef FJCORE_HAVE_EXPLICIT_FOR_OPERATORS 
 #endif
 #ifndef FJCORE_HAVE_GNUCXX_DEPRECATED 
 #endif
 #ifndef FJCORE_HAVE_INTTYPES_H 
 # define FJCORE_HAVE_INTTYPES_H  1 
 #endif
 #ifndef FJCORE_HAVE_LIBM 
 # define FJCORE_HAVE_LIBM  1 
 #endif
 #ifndef FJCORE_HAVE_MEMORY_H 
 # define FJCORE_HAVE_MEMORY_H  1 
 #endif
 #ifndef FJCORE_HAVE_OVERRIDE 
 #endif
 #ifndef FJCORE_HAVE_STDINT_H 
 # define FJCORE_HAVE_STDINT_H  1 
 #endif
 #ifndef FJCORE_HAVE_STDLIB_H 
 # define FJCORE_HAVE_STDLIB_H  1 
 #endif
 #ifndef FJCORE_HAVE_STRINGS_H 
 # define FJCORE_HAVE_STRINGS_H  1 
 #endif
 #ifndef FJCORE_HAVE_STRING_H 
 # define FJCORE_HAVE_STRING_H  1 
 #endif
 #ifndef FJCORE_HAVE_SYS_STAT_H 
 # define FJCORE_HAVE_SYS_STAT_H  1 
 #endif
 #ifndef FJCORE_HAVE_SYS_TYPES_H 
 # define FJCORE_HAVE_SYS_TYPES_H  1 
 #endif
 #ifndef FJCORE_HAVE_UNISTD_H 
 # define FJCORE_HAVE_UNISTD_H  1 
 #endif
 #ifndef FJCORE_LT_OBJDIR 
 # define FJCORE_LT_OBJDIR  ".libs/" 
 #endif
 #ifndef FJCORE_PACKAGE 
 # define FJCORE_PACKAGE  "fastjet" 
 #endif
 #ifndef FJCORE_PACKAGE_BUGREPORT 
 # define FJCORE_PACKAGE_BUGREPORT  "" 
 #endif
 #ifndef FJCORE_PACKAGE_NAME 
 # define FJCORE_PACKAGE_NAME  "FastJet" 
 #endif
 #ifndef FJCORE_PACKAGE_STRING 
 # define FJCORE_PACKAGE_STRING  "FastJet 3.4.0" 
 #endif
 #ifndef FJCORE_PACKAGE_TARNAME 
 # define FJCORE_PACKAGE_TARNAME  "fastjet" 
 #endif
 #ifndef FJCORE_PACKAGE_URL 
 # define FJCORE_PACKAGE_URL  "" 
 #endif
 #ifndef FJCORE_PACKAGE_VERSION 
 # define FJCORE_PACKAGE_VERSION  "3.4.0" 
 #endif
 #ifndef FJCORE_STDC_HEADERS 
 # define FJCORE_STDC_HEADERS  1 
 #endif
 #ifndef FJCORE_VERSION 
 # define FJCORE_VERSION  "3.4.0" 
 #endif
 #ifndef FJCORE_VERSION_MAJOR 
 # define FJCORE_VERSION_MAJOR  3 
 #endif
 #ifndef FJCORE_VERSION_MINOR 
 # define FJCORE_VERSION_MINOR  4 
 #endif
 #ifndef FJCORE_VERSION_NUMBER 
 # define FJCORE_VERSION_NUMBER  30400 
 #endif
 #ifndef FJCORE_VERSION_PATCHLEVEL 
 # define FJCORE_VERSION_PATCHLEVEL  0 
 #endif
 #endif
 #ifndef __FJCORE_CONFIG_H__
 #define __FJCORE_CONFIG_H__
 #endif // __FJCORE_CONFIG_H__
 #ifndef __FJCORE_FASTJET_BASE_HH__
 #define __FJCORE_FASTJET_BASE_HH__
 #define FJCORE_BEGIN_NAMESPACE namespace fjcore {
 #define FJCORE_END_NAMESPACE   }
 #ifdef FJCORE_HAVE_OVERRIDE
 # define FJCORE_OVERRIDE  override
 #else
 # define FJCORE_OVERRIDE  
 #endif
 #endif // __FJCORE_FASTJET_BASE_HH__
 #ifndef __FJCORE_THREAD_SAFETY_HELPERS_HH__
 #define __FJCORE_THREAD_SAFETY_HELPERS_HH__
 #include <limits>
 #ifdef FJCORE_HAVE_LIMITED_THREAD_SAFETY
 #include <atomic>
 FJCORE_BEGIN_NAMESPACE      // defined in fastjet/internal/base.hh
 namespace thread_safety_helpers{
   template<typename T>
   class AtomicCounter{
   public:
     AtomicCounter() : _count{0}{}
     AtomicCounter(const T &count) : _count{count}{}
     AtomicCounter(const AtomicCounter &other) : _count{other._count.load()}{}
     operator T() const{ return _count.load();}
     T get() const{ return _count.load();}
     void set(const T new_value){
       _count.store(new_value);
     }
     T step(){
       T count = _count;
       while (_count < std::numeric_limits<T>::max()
              && !(_count.compare_exchange_strong(count, count+1)));
       return count;
     }
     inline T operator++(){
       return step()+1;
     }
     inline T operator++(int){
       return step();
     }
   private:
     std::atomic<T> _count;  ///< the actual count
   };
   class FirstTimeTrue{
   public:
     FirstTimeTrue(): _first_time{true}{}
     FirstTimeTrue(const FirstTimeTrue &other) : _first_time{other._first_time.load()}{}
     bool operator()(){
       bool expected = true;
       return _first_time.compare_exchange_strong(expected, false,
                                                  std::memory_order_seq_cst,
                                                  std::memory_order_relaxed);
     }
   private:
     std::atomic<bool> _first_time;
   };
 } // namespace thread_safety_helpers
 FJCORE_END_NAMESPACE
 #else  // FJ wo thread-safety features
 FJCORE_BEGIN_NAMESPACE      // defined in fastjet/internal/base.hh
 namespace thread_safety_helpers{
   template<typename T>
   class AtomicCounter{
   public:
     AtomicCounter() : _count(0){}
     AtomicCounter(const T &count) : _count(count){}
     AtomicCounter(const AtomicCounter &other) : _count(other._count){}
     operator T() const{ return _count;}
     T get() const{ return _count;}
     void set(const T new_value){
       _count = new_value;
     }
     T step(){
       unsigned int count = _count;
       if (_count < std::numeric_limits<T>::max()){ _count++; }
       return count;
     }
     inline T operator++(){
       return step()+1;
     }
     inline T operator++(int){
       return step();
     }
   private:
     T _count;  ///< the actual value
   };
   class FirstTimeTrue{
   public:
     FirstTimeTrue(): _first_time(true){}
     bool operator()(){
       if (!_first_time) {return false;}
       _first_time = false;
       return true;
     }
   private:
     bool _first_time;
   };
 } // namespace thread_safety_helpers
 FJCORE_END_NAMESPACE
 #endif // FJCORE_HAVE_LIMITED_THREAD_SAFETY
 #endif // __FJCORE_THREAD_SAFETY_HELPERS_HH__
 #ifndef __FJCORE_NUMCONSTS__
 #define __FJCORE_NUMCONSTS__
 FJCORE_BEGIN_NAMESPACE      // defined in fastjet/internal/base.hh
 const double pi = 3.141592653589793238462643383279502884197;
 const double twopi = 6.283185307179586476925286766559005768394;
 const double pisq  = 9.869604401089358618834490999876151135314;
 const double zeta2 = 1.644934066848226436472415166646025189219;
 const double zeta3 = 1.202056903159594285399738161511449990765;
 const double eulergamma = 0.577215664901532860606512090082402431042;
 const double ln2   = 0.693147180559945309417232121458176568076;
 FJCORE_END_NAMESPACE
 #endif // __FJCORE_NUMCONSTS__
 #ifndef __FJCORE_INTERNAL_IS_BASE_HH__
 #define __FJCORE_INTERNAL_IS_BASE_HH__
 FJCORE_BEGIN_NAMESPACE
 template<typename T, T _t>
 struct integral_type{
   static const T value = _t;         ///< the value (only member carrying info)
   typedef T value_type;          ///< a typedef for the type T
   typedef integral_type<T,_t> type;  ///< a typedef for the whole structure
 };
 template<typename T, T _t>
 const T integral_type<T, _t>::value;
 typedef integral_type<bool, true>  true_type;  ///< the bool 'true'  value promoted to a type
 typedef integral_type<bool, false> false_type; ///< the bool 'false' value promoted to a type
 typedef char (&__yes_type)[1]; //< the yes type
 typedef char (&__no_type) [2]; //< the no type
 template<typename B, typename D>
 struct __inheritance_helper{
 #if !((_MSC_VER !=0 ) && (_MSC_VER == 1310))   // MSVC 7.1
   template <typename T>
   static __yes_type check_sig(D const volatile *, T);
 #else
   static __yes_type check_sig(D const volatile *, long);
 #endif
   static __no_type  check_sig(B const volatile *, int);
 };
 template<typename B, typename D>
 struct IsBaseAndDerived{
 #if ((_MSC_FULL_VER != 0) && (_MSC_FULL_VER >= 140050000))
 #pragma warning(push)
 #pragma warning(disable:6334)
 #endif
   struct Host{
 #if !((_MSC_VER !=0 ) && (_MSC_VER == 1310))
     operator B const volatile *() const;
 #else
     operator B const volatile * const&() const;
 #endif
     operator D const volatile *();
   };
   static const bool value = ((sizeof(B)!=0) && 
                  (sizeof(D)!=0) && 
                  (sizeof(__inheritance_helper<B,D>::check_sig(Host(), 0)) == sizeof(__yes_type)));
 #if ((_MSC_FULL_VER != 0) && (_MSC_FULL_VER >= 140050000))
 #pragma warning(pop)
 #endif
 };
 template<class B, class D>
 B* cast_if_derived(D* d){
   return IsBaseAndDerived<B,D>::value ? (B*)(d) : 0;
 }
 FJCORE_END_NAMESPACE
 #endif  // __IS_BASE_OF_HH__
 #ifndef __FJCORE_FJCORE_DEPRECATED_HH__
 #define __FJCORE_FJCORE_DEPRECATED_HH__
 #ifndef SWIG
 #if defined(FJCORE_HAVE_CXX14_DEPRECATED) && (!defined(__FJCORE__))
 # define FJCORE_DEPRECATED(func)              [[deprecated]] func
 # define FJCORE_DEPRECATED_MSG(message,func)  [[deprecated(message)]] func
 #elif defined(FJCORE_HAVE_GNUCXX_DEPRECATED)
 # define FJCORE_DEPRECATED(func)              func __attribute__((__deprecated__))
 # define FJCORE_DEPRECATED_MSG(message,func)  func __attribute__((__deprecated__))
 #else
 # define FJCORE_DEPRECATED(func)              func
 # define FJCORE_DEPRECATED_MSG(message,func)  func
 #endif
 #else  // SIWG
 # define FJCORE_DEPRECATED(func)              func
 # define FJCORE_DEPRECATED_MSG(message,func)  func
 #endif // SWIG
 #endif // __FJCORE_FJCORE_DEPRECATED_HH__
  #ifndef __FJCORE_SHARED_PTR_HH__
 #define __FJCORE_SHARED_PTR_HH__
 #include <cstdlib>  // for NULL!!!
 #ifdef FJCORE_HAVE_THREAD_SAFETY
 #include <atomic>
 #endif // FJCORE_HAVE_THREAD_SAFETY
 FJCORE_BEGIN_NAMESPACE      // defined in fastjet/internal/base.hh
 #ifdef FJCORE_HAVE_THREAD_SAFETY
 template<class T>
 class SharedPtr{
 public:
   class __SharedCountingPtr;
   SharedPtr() : _ptr(NULL){}
   template<class Y> explicit SharedPtr(Y* ptr){
     _ptr = new __SharedCountingPtr(ptr);
   }
   SharedPtr(SharedPtr const & share) : _ptr(share._get_container()){
     if (_ptr!=NULL) (*_ptr)++;
   }
   ~SharedPtr(){
     if (_ptr==NULL) return;
     _decrease_count();
   }
   void reset(){
     SharedPtr().swap(*this);
   }
   template<class Y> void reset(Y * ptr){
     SharedPtr(ptr).swap(*this);
   }
   template<class Y> void reset(SharedPtr<Y> const & share){
     if (_ptr!=NULL){
       if (_ptr == share._get_container()) return;
       _decrease_count();
     }
     _ptr = share._get_container();  // Note: automatically set it to NULL if share is empty
     if (_ptr!=NULL) (*_ptr)++;
   }
   SharedPtr& operator=(SharedPtr const & share){
     reset(share);
     return *this;
   }
   template<class Y> SharedPtr& operator=(SharedPtr<Y> const & share){
     reset(share);
     return *this;
   }
   inline T& operator*() const{
     return *(_ptr->get());
   }
   inline T* operator->() const{
     if (_ptr==NULL) return NULL;
     return _ptr->get();
   }  
   inline T* get() const{
     if (_ptr==NULL) return NULL;
     return _ptr->get();
   }
   T* operator ()() const{
     if (_ptr==NULL) return NULL;
     return _ptr->get(); // automatically returns NULL when out-of-scope
   }
   inline bool unique() const{
     return (use_count()==1);
   }
   inline long use_count() const{
     if (_ptr==NULL) return 0;
     return _ptr->use_count(); // automatically returns NULL when out-of-scope
   }
   inline operator bool() const{
     return (get()!=NULL);
   }
   inline void swap(SharedPtr & share){
     __SharedCountingPtr* share_container = share._ptr;
     share._ptr = _ptr;
     _ptr = share_container;
   }
   void set_count(const long & count){
     if (_ptr==NULL) return;
     _ptr->set_count(count);
   }
   class __SharedCountingPtr : public std::atomic<long>{
   public:
     __SharedCountingPtr() : std::atomic<long>(0), _ptr(NULL){} 
     template<class Y> explicit __SharedCountingPtr(Y* ptr)
       : std::atomic<long>(1), _ptr(ptr){}
     ~__SharedCountingPtr(){ 
       if (_ptr!=NULL){ delete _ptr;}
     }
     inline T* get() const {return _ptr;}
     inline long use_count() const {return (long)(*this);}
     inline void set_count(const long & count){ store(count);}
   private:
     T *_ptr;               ///< the pointer we're counting the references to
   };
 private:
   inline __SharedCountingPtr* _get_container() const{
     return _ptr;
   }
   void _decrease_count(){
     if (((*_ptr)--) == 1)
       delete _ptr;
   }
   __SharedCountingPtr *_ptr;
 };
 template<class T,class U>
 inline bool operator==(SharedPtr<T> const & t, SharedPtr<U> const & u){
   return t.get() == u.get();
 }
 template<class T,class U>
 inline bool operator!=(SharedPtr<T> const & t, SharedPtr<U> const & u){
   return t.get() != u.get();
 }
 template<class T,class U>
 inline bool operator<(SharedPtr<T> const & t, SharedPtr<U> const & u){
   return t.get() < u.get();
 }
 template<class T>
 inline void swap(SharedPtr<T> & a, SharedPtr<T> & b){
   return a.swap(b);
 }
 template<class T>
 inline T* get_pointer(SharedPtr<T> const & t){
   return t.get();
 }
 #else  // FJCORE_HAVE_THREAD_SAFETY
 template<class T>
 class SharedPtr{
 public:
   class __SharedCountingPtr;
   SharedPtr() : _ptr(NULL){}
   template<class Y> explicit SharedPtr(Y* ptr){
     _ptr = new __SharedCountingPtr(ptr);
   }
   SharedPtr(SharedPtr const & share) : _ptr(share._get_container()){
     if (_ptr!=NULL) ++(*_ptr);
   }
   ~SharedPtr(){
     if (_ptr==NULL) return;
     _decrease_count();
   }
   void reset(){
     SharedPtr().swap(*this);
   }
   template<class Y> void reset(Y * ptr){
     SharedPtr(ptr).swap(*this);
   }
   template<class Y> void reset(SharedPtr<Y> const & share){
     if (_ptr!=NULL){
       if (_ptr == share._get_container()) return;
       _decrease_count();
     }
     _ptr = share._get_container();  // Note: automatically set it to NULL if share is empty
     if (_ptr!=NULL) ++(*_ptr);
   }
   SharedPtr& operator=(SharedPtr const & share){
     reset(share);
     return *this;
   }
   template<class Y> SharedPtr& operator=(SharedPtr<Y> const & share){
     reset(share);
     return *this;
   }
   FJCORE_DEPRECATED_MSG("Use SharedPtr<T>::get() instead",
   T* operator ()() const){
     if (_ptr==NULL) return NULL;
     return _ptr->get(); // automatically returns NULL when out-of-scope
   }
   inline T& operator*() const{
     return *(_ptr->get());
   }
   inline T* operator->() const{
     if (_ptr==NULL) return NULL;
     return _ptr->get();
   }  
   inline T* get() const{
     if (_ptr==NULL) return NULL;
     return _ptr->get();
   }
   inline bool unique() const{
     return (use_count()==1);
   }
   inline long use_count() const{
     if (_ptr==NULL) return 0;
     return _ptr->use_count(); // automatically returns NULL when out-of-scope
   }
   #ifdef FJCORE_HAVE_EXPLICIT_FOR_OPERATORS
   explicit
   #endif
   inline operator bool() const{
     return (get()!=NULL);
   }
   inline void swap(SharedPtr & share){
     __SharedCountingPtr* share_container = share._ptr;
     share._ptr = _ptr;
     _ptr = share_container;
   }
   void set_count(const long & count){
     if (_ptr==NULL) return;
     _ptr->set_count(count);
   }
   class __SharedCountingPtr{
   public:
     __SharedCountingPtr() : _ptr(NULL), _count(0){}
     template<class Y> explicit __SharedCountingPtr(Y* ptr) : _ptr(ptr), _count(1){}
     ~__SharedCountingPtr(){ 
       if (_ptr!=NULL){ delete _ptr;}
     }
     inline T* get() const {return _ptr;}
     inline long use_count() const {return _count;}
     inline long operator++(){return ++_count;}
     inline long operator--(){return --_count;}
     inline long operator++(int){return _count++;}
     inline long operator--(int){return _count--;}
     void set_count(const long & count){
       _count = count;
     }
   private:
     T *_ptr;      ///< the pointer we're counting the references to
     long _count;  ///< the number of references
   };
 private:
   inline __SharedCountingPtr* _get_container() const{
     return _ptr;
   }
   void _decrease_count(){
     (*_ptr)--;
     if (_ptr->use_count()==0)
       delete _ptr; // that automatically deletes the object itself
   }
   __SharedCountingPtr *_ptr;
 };
 template<class T,class U>
 inline bool operator==(SharedPtr<T> const & t, SharedPtr<U> const & u){
   return t.get() == u.get();
 }
 template<class T,class U>
 inline bool operator!=(SharedPtr<T> const & t, SharedPtr<U> const & u){
   return t.get() != u.get();
 }
 template<class T,class U>
 inline bool operator<(SharedPtr<T> const & t, SharedPtr<U> const & u){
   return t.get() < u.get();
 }
 template<class T>
 inline void swap(SharedPtr<T> & a, SharedPtr<T> & b){
   return a.swap(b);
 }
 template<class T>
 inline T* get_pointer(SharedPtr<T> const & t){
   return t.get();
 }
 #endif // FJCORE_HAVE_THREAD_SAFETY
 FJCORE_END_NAMESPACE      // defined in fastjet/internal/base.hh
 #endif   // __FJCORE_SHARED_PTR_HH__
 #ifndef __FJCORE_LIMITEDWARNING_HH__
 #define __FJCORE_LIMITEDWARNING_HH__
 #include <iostream>
 #include <string>
 #include <list>
 #ifdef FJCORE_HAVE_LIMITED_THREAD_SAFETY
 #include <atomic>
 #include <mutex>
 #endif // FJCORE_HAVE_LIMITED_THREAD_SAFETY
 FJCORE_BEGIN_NAMESPACE
 class LimitedWarning {
 public:
   LimitedWarning() : _max_warn(_max_warn_default),_this_warning_summary(0) {}
   LimitedWarning(int max_warn_in) : _max_warn(max_warn_in), _this_warning_summary(0) {}  
 #ifdef FJCORE_HAVE_LIMITED_THREAD_SAFETY
   LimitedWarning(const LimitedWarning &other)
     : _max_warn(other._max_warn), _this_warning_summary{other._this_warning_summary.load()} {}  
 #endif
   void warn(const char * warning) {warn(warning, _default_ostr);}
   void warn(const std::string & warning) {warn(warning.c_str(), _default_ostr);}
   void warn(const char * warning, std::ostream * ostr);
   void warn(const std::string & warning, std::ostream * ostr) {warn(warning.c_str(), ostr);}
   static void set_default_stream(std::ostream * ostr) {
     _default_ostr = ostr;
   }
 #ifdef FJCORE_HAVE_LIMITED_THREAD_SAFETY
   static void set_default_stream_and_mutex(std::ostream * ostr,
                                            std::mutex * warnings_mutex) {
     _default_ostr  = ostr;
     _stream_mutex = warnings_mutex;
   }
 #endif // FJCORE_HAVE_LIMITED_THREAD_SAFETY
   static void set_default_max_warn(int max_warn) {
     _max_warn_default = max_warn;
   }
   int max_warn() const {return _max_warn;}
   int n_warn_so_far() const;
   static std::string summary();
 private:
   const int _max_warn;
   typedef std::pair<std::string, thread_safety_helpers::AtomicCounter<unsigned int> > Summary;
 #ifdef FJCORE_HAVE_LIMITED_THREAD_SAFETY
   static std::atomic<int> _max_warn_default;
   static std::atomic<std::ostream *> _default_ostr;
   static std::atomic<std::mutex *> _stream_mutex;
   static std::mutex _global_warnings_summary_mutex;
   std::atomic<Summary*> _this_warning_summary;
 #else
   static int _max_warn_default;
   static std::ostream * _default_ostr;
   Summary* _this_warning_summary;
 #endif // FJCORE_HAVE_LIMITED_THREAD_SAFETY
   static std::list< Summary > _global_warnings_summary;
 };
 FJCORE_END_NAMESPACE
 #endif // __FJCORE_LIMITEDWARNING_HH__
  #ifndef __FJCORE_ERROR_HH__
 #define __FJCORE_ERROR_HH__
 #include<iostream>
 #include<string>
 #if (!defined(FJCORE_HAVE_EXECINFO_H)) || defined(__FJCORE__)
 #endif
 #ifdef FJCORE_HAVE_LIMITED_THREAD_SAFETY
 #include <atomic>
 #include <mutex>
 #endif // FJCORE_HAVE_LIMITED_THREAD_SAFETY
 FJCORE_BEGIN_NAMESPACE      // defined in fastjet/internal/base.hh
 class Error{
 public:
   Error() {}
   Error(const std::string & message);
   virtual ~Error() {}
   std::string message() const {return _message;}
   std::string description() const {return message();}
   static void set_print_errors(bool print_errors) {_print_errors = print_errors;}
   static void set_print_backtrace(bool enabled);
   static void set_default_stream(std::ostream * ostr) {
     _default_ostr = ostr;
   }
 #ifdef FJCORE_HAVE_LIMITED_THREAD_SAFETY
   static void set_default_stream_and_mutex(std::ostream * ostr, std::mutex * stream_mutex) {
     _default_ostr = ostr;
     _stream_mutex = stream_mutex;
   }
 #endif // FJCORE_HAVE_LIMITED_THREAD_SAFETY
 private:
   std::string _message;                ///< error message
 #ifdef FJCORE_HAVE_LIMITED_THREAD_SAFETY
   static std::atomic<bool> _print_errors;           ///< do we print anything?
   static std::atomic<bool> _print_backtrace;        ///< do we print the backtrace?
   static std::atomic<std::ostream *> _default_ostr; ///< the output stream (cerr if not set)
   static std::atomic<std::mutex *> _stream_mutex; ///< the mutex for the output stream (nullptr if not set)
 #else
   static bool _print_errors;           ///< do we print anything?
   static bool _print_backtrace;        ///< do we print the backtrace?
   static std::ostream * _default_ostr; ///< the output stream (cerr if not set)
 #endif // FJCORE_HAVE_LIMITED_THREAD_SAFETY
 #if (!defined(FJCORE_HAVE_EXECINFO_H)) || defined(__FJCORE__)
   static LimitedWarning _execinfo_undefined;
 #endif
 };
 class InternalError : public Error{
 public:
   InternalError(const std::string & message_in) : Error(std::string("*** CRITICAL INTERNAL FASTJET ERROR *** CONTACT THE AUTHORS *** ") + message_in){ }
 };
 FJCORE_END_NAMESPACE
 #endif // __FJCORE_ERROR_HH__
 #ifndef __FJCORE_PSEUDOJET_STRUCTURE_BASE_HH__
 #define __FJCORE_PSEUDOJET_STRUCTURE_BASE_HH__
 #include <vector>
 #include <string>
 FJCORE_BEGIN_NAMESPACE      // defined in fastjet/internal/base.hh
 class PseudoJet;
 class ClusterSequence;
 class PseudoJetStructureBase{
 public:
   PseudoJetStructureBase(){};
   virtual ~PseudoJetStructureBase(){};
   virtual std::string description() const{ return "PseudoJet with an unknown structure"; }
   virtual bool has_associated_cluster_sequence() const { return false;}
   virtual const ClusterSequence* associated_cluster_sequence() const;
   virtual bool has_valid_cluster_sequence() const {return false;}
   virtual const ClusterSequence * validated_cs() const;
   virtual bool has_partner(const PseudoJet &reference, PseudoJet &partner) const;
   virtual bool has_child(const PseudoJet &reference, PseudoJet &child) const;
   virtual bool has_parents(const PseudoJet &reference, PseudoJet &parent1, PseudoJet &parent2) const;
   virtual bool object_in_jet(const PseudoJet &reference, const PseudoJet &jet) const;
   virtual bool has_constituents() const {return false;}
   virtual std::vector<PseudoJet> constituents(const PseudoJet &reference) const;
   virtual bool has_exclusive_subjets() const {return false;}
   virtual std::vector<PseudoJet> exclusive_subjets(const PseudoJet &reference, const double & dcut) const;
   virtual int n_exclusive_subjets(const PseudoJet &reference, const double & dcut) const;
   virtual std::vector<PseudoJet> exclusive_subjets_up_to (const PseudoJet &reference, int nsub) const;
   virtual double exclusive_subdmerge(const PseudoJet &reference, int nsub) const;
   virtual double exclusive_subdmerge_max(const PseudoJet &reference, int nsub) const;
   virtual bool has_pieces(const PseudoJet & /* reference */) const {
     return false;}
   virtual std::vector<PseudoJet> pieces(const PseudoJet & /* reference */
                                         ) const;
 };
 FJCORE_END_NAMESPACE
 #endif  //  __FJCORE_PSEUDOJET_STRUCTURE_BASE_HH__
 #ifndef __FJCORE_PSEUDOJET_HH__
 #define __FJCORE_PSEUDOJET_HH__
 #include<valarray>
 #include<vector>
 #include<cassert>
 #include<cmath>
 #include<iostream>
 FJCORE_BEGIN_NAMESPACE      // defined in fastjet/internal/base.hh
 const double MaxRap = 1e5;
 const double pseudojet_invalid_phi = -100.0;
 const double pseudojet_invalid_rap = -1e200;
 class PseudoJet {
  public:
   PseudoJet() : _px(0), _py(0), _pz(0), _E(0) {_finish_init(); _reset_indices();}
   PseudoJet(const double px, const double py, const double pz, const double E);
   #ifndef SWIG
   template <class L> PseudoJet(const L & some_four_vector);
   #endif
   PseudoJet(bool /* dummy */) {}
 #ifdef FJCORE_HAVE_THREAD_SAFETY
   PseudoJet(const PseudoJet &other){ (*this)=other; }
   PseudoJet& operator=(const PseudoJet& other);
 #endif
   virtual ~PseudoJet(){}
   inline double E()   const {return _E;}
   inline double e()   const {return _E;} // like CLHEP
   inline double px()  const {return _px;}
   inline double py()  const {return _py;}
   inline double pz()  const {return _pz;}
   inline double phi() const {return phi_02pi();}
   inline double phi_std()  const {
     _ensure_valid_rap_phi();
     return _phi > pi ? _phi-twopi : _phi;}
   inline double phi_02pi() const {
     _ensure_valid_rap_phi();
     return _phi;
   }
   inline double rap() const {
     _ensure_valid_rap_phi();
     return _rap;
   }
   inline double rapidity() const {return rap();} // like CLHEP
   double pseudorapidity() const;
   double eta() const {return pseudorapidity();}
   inline double pt2() const {return _kt2;}
   inline double  pt() const {return sqrt(_kt2);} 
   inline double perp2() const {return _kt2;}  // like CLHEP
   inline double  perp() const {return sqrt(_kt2);}    // like CLHEP
   inline double kt2() const {return _kt2;} // for bkwds compatibility
   inline double  m2() const {return (_E+_pz)*(_E-_pz)-_kt2;}    
   inline double  m() const;    
   inline double mperp2() const {return (_E+_pz)*(_E-_pz);}
   inline double mperp() const {return sqrt(std::abs(mperp2()));}
   inline double mt2() const {return (_E+_pz)*(_E-_pz);}
   inline double mt() const {return sqrt(std::abs(mperp2()));}
   inline double modp2() const {return _kt2+_pz*_pz;}
   inline double modp() const {return sqrt(_kt2+_pz*_pz);}
   inline double Et() const {return (_kt2==0) ? 0.0 : _E/sqrt(1.0+_pz*_pz/_kt2);}
   inline double Et2() const {return (_kt2==0) ? 0.0 : _E*_E/(1.0+_pz*_pz/_kt2);}
   inline double cos_theta() const {
     return std::min(1.0, std::max(-1.0, _pz/sqrt(modp2())));
   }
   inline double theta() const { return acos(cos_theta()); }
   double operator () (int i) const ; 
   inline double operator [] (int i) const { return (*this)(i); }; // this too
   double kt_distance(const PseudoJet & other) const;
   double plain_distance(const PseudoJet & other) const;
   inline double squared_distance(const PseudoJet & other) const {
     return plain_distance(other);}
   inline double delta_R(const PseudoJet & other) const {
     return sqrt(squared_distance(other));
   }
   double delta_phi_to(const PseudoJet & other) const;
   inline double beam_distance() const {return _kt2;}
   std::valarray<double> four_mom() const;
   enum { X=0, Y=1, Z=2, T=3, NUM_COORDINATES=4, SIZE=NUM_COORDINATES };
   PseudoJet & boost(const PseudoJet & prest);
   PseudoJet & unboost(const PseudoJet & prest);
   PseudoJet & operator*=(double);
   PseudoJet & operator/=(double);
   PseudoJet & operator+=(const PseudoJet &);
   PseudoJet & operator-=(const PseudoJet &);
   inline void reset(double px, double py, double pz, double E);
   inline void reset(const PseudoJet & psjet) {
     (*this) = psjet;
   }
 #ifndef SWIG
   template <class L> inline void reset(const L & some_four_vector) {
     const PseudoJet * pj = fjcore::cast_if_derived<const PseudoJet>(&some_four_vector);
     if (pj){
       (*this) = *pj;
     } else {
       reset(some_four_vector[0], some_four_vector[1],
         some_four_vector[2], some_four_vector[3]);
     }
   }
 #endif // SWIG
   inline void reset_PtYPhiM(double pt_in, double y_in, double phi_in, double m_in=0.0) {
     reset_momentum_PtYPhiM(pt_in, y_in, phi_in, m_in);
     _reset_indices();
   }
   inline void reset_momentum(double px, double py, double pz, double E);
   inline void reset_momentum(const PseudoJet & pj);
   void reset_momentum_PtYPhiM(double pt, double y, double phi, double m=0.0);
   template <class L> inline void reset_momentum(const L & some_four_vector) {
     reset_momentum(some_four_vector[0], some_four_vector[1],
            some_four_vector[2], some_four_vector[3]);
   }
   void set_cached_rap_phi(double rap, double phi);
   inline int user_index() const {return _user_index;}
   inline void set_user_index(const int index) {_user_index = index;}
   class UserInfoBase{
   public:
     UserInfoBase(){};
     virtual ~UserInfoBase(){}; 
   };
   class InexistentUserInfo : public Error {
   public:
     InexistentUserInfo();
   };
   void set_user_info(UserInfoBase * user_info_in) {
     _user_info.reset(user_info_in);
   }
   template<class L>
   const L & user_info() const{
     if (_user_info.get() == 0) throw InexistentUserInfo();
     return dynamic_cast<const L &>(* _user_info.get());
   }
   bool has_user_info() const{
     return _user_info.get();
   }
   template<class L>
   bool has_user_info() const{
     return _user_info.get() && dynamic_cast<const L *>(_user_info.get());
   }
   const UserInfoBase * user_info_ptr() const{
     return _user_info.get();
   }
   const SharedPtr<UserInfoBase> & user_info_shared_ptr() const{
     return _user_info;
   }
   SharedPtr<UserInfoBase> & user_info_shared_ptr(){
     return _user_info;
   }
   std::string description() const;
   bool has_associated_cluster_sequence() const;
   bool has_associated_cs() const {return has_associated_cluster_sequence();}
   bool has_valid_cluster_sequence() const;
   bool has_valid_cs() const {return has_valid_cluster_sequence();}
   const ClusterSequence* associated_cluster_sequence() const;
   const ClusterSequence* associated_cs() const {return associated_cluster_sequence();}
   inline const ClusterSequence * validated_cluster_sequence() const {
     return validated_cs();
   }
   const ClusterSequence * validated_cs() const;
   void set_structure_shared_ptr(const SharedPtr<PseudoJetStructureBase> &structure_in);
   bool has_structure() const;
   const PseudoJetStructureBase* structure_ptr() const;
   PseudoJetStructureBase* structure_non_const_ptr();
   const PseudoJetStructureBase* validated_structure_ptr() const;
   const SharedPtr<PseudoJetStructureBase> & structure_shared_ptr() const;
   template<typename StructureType>
   const StructureType & structure() const;
   template<typename TransformerType>
   bool has_structure_of() const;
   template<typename TransformerType>
   const typename TransformerType::StructureType & structure_of() const;
   virtual bool has_partner(PseudoJet &partner) const;
   virtual bool has_child(PseudoJet &child) const;
   virtual bool has_parents(PseudoJet &parent1, PseudoJet &parent2) const;
   virtual bool contains(const PseudoJet &constituent) const;
   virtual bool is_inside(const PseudoJet &jet) const;
   virtual bool has_constituents() const;
   virtual std::vector<PseudoJet> constituents() const;
   virtual bool has_exclusive_subjets() const;
   std::vector<PseudoJet> exclusive_subjets (const double dcut) const;
   int n_exclusive_subjets(const double dcut) const;
   std::vector<PseudoJet> exclusive_subjets (int nsub) const;
   std::vector<PseudoJet> exclusive_subjets_up_to (int nsub) const;
   double exclusive_subdmerge(int nsub) const;
   double exclusive_subdmerge_max(int nsub) const;
   virtual bool has_pieces() const;
   virtual std::vector<PseudoJet> pieces() const;
   inline int cluster_hist_index() const {return _cluster_hist_index;}
   inline void set_cluster_hist_index(const int index) {_cluster_hist_index = index;}
   inline int cluster_sequence_history_index() const {
     return cluster_hist_index();}
   inline void set_cluster_sequence_history_index(const int index) {
     set_cluster_hist_index(index);}
  protected:  
   SharedPtr<PseudoJetStructureBase> _structure;
   SharedPtr<UserInfoBase> _user_info;
  private: 
   double _px,_py,_pz,_E;
   mutable double _phi, _rap;
   double _kt2; 
   int    _cluster_hist_index, _user_index;
 #ifdef FJCORE_HAVE_THREAD_SAFETY
   enum {
     Init_Done=1,
     Init_NotDone=0,
     Init_InProgress=-1
   };
   mutable std::atomic<int> _init_status;
 #endif
   void _finish_init();
   void _reset_indices();
 #ifdef FJCORE_HAVE_THREAD_SAFETY
   void _ensure_valid_rap_phi() const;
 #else
   inline void _ensure_valid_rap_phi() const{
     if (_phi == pseudojet_invalid_phi) _set_rap_phi();
   }
 #endif
   void _set_rap_phi() const;
   friend PseudoJet operator*(double, const PseudoJet &);
 };
 PseudoJet operator+(const PseudoJet &, const PseudoJet &);
 PseudoJet operator-(const PseudoJet &, const PseudoJet &);
 PseudoJet operator*(double, const PseudoJet &);
 PseudoJet operator*(const PseudoJet &, double);
 PseudoJet operator/(const PseudoJet &, double);
 bool operator==(const PseudoJet &, const PseudoJet &);
 inline bool operator!=(const PseudoJet & a, const PseudoJet & b) {return !(a==b);}
 bool operator==(const PseudoJet & jet, const double val);
 inline bool operator==(const double val, const PseudoJet & jet) {return jet == val;}
 inline bool operator!=(const PseudoJet & a, const double val)  {return !(a==val);}
 inline bool operator!=( const double val, const PseudoJet & a) {return !(a==val);}
 inline double dot_product(const PseudoJet & a, const PseudoJet & b) {
   return a.E()*b.E() - a.px()*b.px() - a.py()*b.py() - a.pz()*b.pz();
 }
 inline double cos_theta(const PseudoJet & a, const PseudoJet & b) {
   double dot_3d = a.px()*b.px() + a.py()*b.py() + a.pz()*b.pz();
   return std::min(1.0, std::max(-1.0, dot_3d/sqrt(a.modp2()*b.modp2())));
 }
 inline double theta(const PseudoJet & a, const PseudoJet & b) {
   return acos(cos_theta(a,b));
 }
 bool have_same_momentum(const PseudoJet &, const PseudoJet &);
 PseudoJet PtYPhiM(double pt, double y, double phi, double m = 0.0);
 std::vector<PseudoJet> sorted_by_pt(const std::vector<PseudoJet> & jets);
 std::vector<PseudoJet> sorted_by_rapidity(const std::vector<PseudoJet> & jets);
 std::vector<PseudoJet> sorted_by_E(const std::vector<PseudoJet> & jets);
 std::vector<PseudoJet> sorted_by_pz(const std::vector<PseudoJet> & jets);
 void sort_indices(std::vector<int> & indices, 
           const std::vector<double> & values);
 template<class T> std::vector<T> objects_sorted_by_values(const std::vector<T> & objects, 
                           const std::vector<double> & values) {
   if (objects.size() != values.size()){
     throw Error("fjcore::objects_sorted_by_values(...): the size of the 'objects' vector must match the size of the 'values' vector");
   }
   std::vector<int> indices(values.size());
   for (size_t i = 0; i < indices.size(); i++) {indices[i] = i;}
   sort_indices(indices, values);
   std::vector<T> objects_sorted(objects.size());
   for (size_t i = 0; i < indices.size(); i++) {
     objects_sorted[i] = objects[indices[i]];
   }
   return objects_sorted;
 }
 class IndexedSortHelper {
 public:
   inline IndexedSortHelper (const std::vector<double> * reference_values) {
     _ref_values = reference_values;
   };
   inline int operator() (const int i1, const int i2) const {
     return  (*_ref_values)[i1] < (*_ref_values)[i2];
   };
 private:
   const std::vector<double> * _ref_values;
 };
 #ifndef SWIG
 template <class L> inline  PseudoJet::PseudoJet(const L & some_four_vector) {
   reset(some_four_vector);
 }
 #endif
 inline void PseudoJet::_reset_indices() { 
   set_cluster_hist_index(-1);
   set_user_index(-1);
   _structure.reset();
   _user_info.reset();
 }
 inline double PseudoJet::m() const {
   double mm = m2();
   return mm < 0.0 ? -std::sqrt(-mm) : std::sqrt(mm);
 }
 inline void PseudoJet::reset(double px_in, double py_in, double pz_in, double E_in) {
   _px = px_in;
   _py = py_in;
   _pz = pz_in;
   _E  = E_in;
   _finish_init();
   _reset_indices();
 }
 inline void PseudoJet::reset_momentum(double px_in, double py_in, double pz_in, double E_in) {
   _px = px_in;
   _py = py_in;
   _pz = pz_in;
   _E  = E_in;
   _finish_init();
 }
 inline void PseudoJet::reset_momentum(const PseudoJet & pj) {
   _px  = pj._px ;
   _py  = pj._py ;
   _pz  = pj._pz ;
   _E   = pj._E  ;
   _phi = pj._phi;
   _rap = pj._rap;
   _kt2 = pj._kt2;
 }
 template<typename StructureType>
 const StructureType & PseudoJet::structure() const{
   return dynamic_cast<const StructureType &>(* validated_structure_ptr());
 }
 template<typename TransformerType>
 bool PseudoJet::has_structure_of() const{
   if (!_structure) return false;
   return dynamic_cast<const typename TransformerType::StructureType *>(_structure.get()) != 0;
 }
 template<typename TransformerType>
 const typename TransformerType::StructureType & PseudoJet::structure_of() const{
   if (!_structure) 
     throw Error("Trying to access the structure of a PseudoJet without an associated structure");
   return dynamic_cast<const typename TransformerType::StructureType &>(*_structure);
 }
 PseudoJet join(const std::vector<PseudoJet> & pieces);
 PseudoJet join(const PseudoJet & j1);
 PseudoJet join(const PseudoJet & j1, const PseudoJet & j2);
 PseudoJet join(const PseudoJet & j1, const PseudoJet & j2, const PseudoJet & j3);
 PseudoJet join(const PseudoJet & j1, const PseudoJet & j2, const PseudoJet & j3, const PseudoJet & j4);
 FJCORE_END_NAMESPACE
 #endif // __FJCORE_PSEUDOJET_HH__
 #ifndef __FJCORE_FUNCTION_OF_PSEUDOJET_HH__
 #define __FJCORE_FUNCTION_OF_PSEUDOJET_HH__
 FJCORE_BEGIN_NAMESPACE
 template<typename TOut>
 class FunctionOfPseudoJet{
 public:
   FunctionOfPseudoJet(){}
   virtual ~FunctionOfPseudoJet(){}
   virtual std::string description() const{ return "";}
   virtual TOut result(const PseudoJet &pj) const = 0;
   TOut operator()(const PseudoJet &pj) const { return result(pj);}
   std::vector<TOut> operator()(const std::vector<PseudoJet> &pjs) const {
     std::vector<TOut> res(pjs.size());
     for (unsigned int i=0; i<pjs.size(); i++)
       res[i] = result(pjs[i]);
     return res;
   }
 };
 FJCORE_END_NAMESPACE
 #endif  // __FJCORE_FUNCTION_OF_PSEUDOJET_HH__
 #ifndef __FJCORE_SELECTOR_HH__
 #define __FJCORE_SELECTOR_HH__
 #include <limits>
 #include <cmath>
 FJCORE_BEGIN_NAMESPACE      // defined in fastjet/internal/base.hh
 class Selector;
 class SelectorWorker {
 public:
   virtual ~SelectorWorker() {}
   virtual bool pass(const PseudoJet & jet) const = 0;
   virtual void terminator(std::vector<const PseudoJet *> & jets) const {
     for (unsigned i = 0; i < jets.size(); i++) {
       if (jets[i] && !pass(*jets[i])) jets[i] = NULL;
     }
   }
   virtual bool applies_jet_by_jet() const {return true;}
   virtual std::string description() const {return "missing description";}
   virtual bool takes_reference() const { return false;}
   virtual void set_reference(const PseudoJet & /*reference*/){
     throw Error("set_reference(...) cannot be used for a selector worker that does not take a reference");
   }
   virtual SelectorWorker* copy(){ 
     throw Error("this SelectorWorker has nothing to copy");
   }
   virtual void get_rapidity_extent(double & rapmin, double & rapmax) const {
     rapmax = std::numeric_limits<double>::infinity();
     rapmin = -rapmax; 
   }
   virtual bool is_geometric() const { return false;}
   virtual bool has_finite_area() const;
   virtual bool has_known_area() const { return false;}
   virtual double known_area() const{
     throw Error("this selector has no computable area");
   }
 };
 class Selector{
 public:
   Selector() {}
   Selector(SelectorWorker * worker_in) {_worker.reset(worker_in);}
   virtual ~Selector(){}
   bool pass(const PseudoJet & jet) const {
     if (!validated_worker()->applies_jet_by_jet()) {
       throw Error("Cannot apply this selector to an individual jet");
     }
     return _worker->pass(jet);
   }
   bool operator()(const PseudoJet & jet) const {
     return pass(jet);
   }
   unsigned int count(const std::vector<PseudoJet> & jets) const;
   PseudoJet sum(const std::vector<PseudoJet> & jets) const;
   double scalar_pt_sum(const std::vector<PseudoJet> & jets) const;
   void sift(const std::vector<PseudoJet> & jets,
           std::vector<PseudoJet> & jets_that_pass,
           std::vector<PseudoJet> & jets_that_fail) const;
   bool applies_jet_by_jet() const {
     return validated_worker()->applies_jet_by_jet();
   }
   std::vector<PseudoJet> operator()(const std::vector<PseudoJet> & jets) const;
   virtual void nullify_non_selected(std::vector<const PseudoJet *> & jets) const {
     validated_worker()->terminator(jets);
   }
   void get_rapidity_extent(double &rapmin, double &rapmax) const {
     return validated_worker()->get_rapidity_extent(rapmin, rapmax);
   }
   std::string description() const {
     return validated_worker()->description();
   }
   bool is_geometric() const{
     return validated_worker()->is_geometric();
   }
   bool has_finite_area() const{
     return validated_worker()->has_finite_area();
   }
   const SharedPtr<SelectorWorker> & worker() const {return _worker;}
   const SelectorWorker* validated_worker() const {
     const SelectorWorker* worker_ptr = _worker.get();
     if (worker_ptr == 0) throw InvalidWorker();
     return worker_ptr;
   }
   bool takes_reference() const {
     return validated_worker()->takes_reference();
   }
   const Selector & set_reference(const PseudoJet &reference){
     if (! validated_worker()->takes_reference()){
       return *this;
     }
     _copy_worker_if_needed();
     _worker->set_reference(reference);
     return *this;
   }
   class InvalidWorker : public Error {
   public:
     InvalidWorker() : Error("Attempt to use Selector with no valid underlying worker") {}
   };
   class InvalidArea : public Error {
   public:
     InvalidArea() : Error("Attempt to obtain area from Selector for which this is not meaningful") {}
   };
   Selector & operator &=(const Selector & b);
   Selector & operator |=(const Selector & b);
 protected:
   void _copy_worker_if_needed(){
     if (_worker.unique()) return;
     _worker.reset(_worker->copy());
   }
 private:
   SharedPtr<SelectorWorker> _worker; ///< the underlying worker
 };
 Selector SelectorIdentity();
 Selector operator!(const Selector & s);
 Selector operator ||(const Selector & s1, const Selector & s2);
 Selector operator&&(const Selector & s1, const Selector & s2);
 Selector operator*(const Selector & s1, const Selector & s2);
 Selector SelectorPtMin(double ptmin);                    ///< select objects with pt >= ptmin
 Selector SelectorPtMax(double ptmax);                    ///< select objects with pt <= ptmax
 Selector SelectorPtRange(double ptmin, double ptmax);    ///< select objects with ptmin <= pt <= ptmax
 Selector SelectorEtMin(double Etmin);                    ///< select objects with Et >= Etmin
 Selector SelectorEtMax(double Etmax);                    ///< select objects with Et <= Etmax
 Selector SelectorEtRange(double Etmin, double Etmax);    ///< select objects with Etmin <= Et <= Etmax
 Selector SelectorEMin(double Emin);                      ///< select objects with E >= Emin
 Selector SelectorEMax(double Emax);                      ///< select objects with E <= Emax
 Selector SelectorERange(double Emin, double Emax);       ///< select objects with Emin <= E <= Emax
 Selector SelectorMassMin(double Mmin);                      ///< select objects with Mass >= Mmin
 Selector SelectorMassMax(double Mmax);                      ///< select objects with Mass <= Mmax
 Selector SelectorMassRange(double Mmin, double Mmax);       ///< select objects with Mmin <= Mass <= Mmax
 Selector SelectorRapMin(double rapmin);                  ///< select objects with rap >= rapmin
 Selector SelectorRapMax(double rapmax);                  ///< select objects with rap <= rapmax
 Selector SelectorRapRange(double rapmin, double rapmax); ///< select objects with rapmin <= rap <= rapmax
 Selector SelectorAbsRapMin(double absrapmin);                     ///< select objects with |rap| >= absrapmin
 Selector SelectorAbsRapMax(double absrapmax);                     ///< select objects with |rap| <= absrapmax
 Selector SelectorAbsRapRange(double absrapmin, double absrapmax); ///< select objects with absrapmin <= |rap| <= absrapmax
 Selector SelectorEtaMin(double etamin);                  ///< select objects with eta >= etamin
 Selector SelectorEtaMax(double etamax);                  ///< select objects with eta <= etamax
 Selector SelectorEtaRange(double etamin, double etamax); ///< select objects with etamin <= eta <= etamax
 Selector SelectorAbsEtaMin(double absetamin);                     ///< select objects with |eta| >= absetamin
 Selector SelectorAbsEtaMax(double absetamax);                     ///< select objects with |eta| <= absetamax
 Selector SelectorAbsEtaRange(double absetamin, double absetamax); ///< select objects with absetamin <= |eta| <= absetamax
 Selector SelectorPhiRange(double phimin, double phimax); ///< select objects with phimin <= phi <= phimax
 Selector SelectorRapPhiRange(double rapmin, double rapmax, double phimin, double phimax);
 Selector SelectorNHardest(unsigned int n); 
 Selector SelectorCircle(const double radius); 
 Selector SelectorDoughnut(const double radius_in, const double radius_out); 
 Selector SelectorStrip(const double half_width);
 Selector SelectorRectangle(const double half_rap_width, const double half_phi_width);
 Selector SelectorPtFractionMin(double fraction);
 Selector SelectorIsZero();
 FJCORE_END_NAMESPACE      // defined in fastjet/internal/base.hh
 #endif // __FJCORE_SELECTOR_HH__
 #ifndef __FJCORE_JETDEFINITION_HH__
 #define __FJCORE_JETDEFINITION_HH__
 #include<cassert>
 #include<string>
 #include<memory>
 FJCORE_BEGIN_NAMESPACE      // defined in fastjet/internal/base.hh
 std::string fastjet_version_string();
 enum Strategy {
   N2MHTLazy9AntiKtSeparateGhosts   = -10, 
   N2MHTLazy9   = -7, 
   N2MHTLazy25   = -6, 
   N2MHTLazy9Alt   = -5, 
   N2MinHeapTiled   = -4, 
   N2Tiled     = -3, 
   N2PoorTiled = -2, 
   N2Plain     = -1, 
   N3Dumb      =  0, 
   Best        =  1, 
   NlnN        =  2, 
   NlnN3pi     =  3, 
   NlnN4pi     =  4,
   NlnNCam4pi   = 14,
   NlnNCam2pi2R = 13,
   NlnNCam      = 12, // 2piMultD
   BestFJ30     =  21, 
   plugin_strategy = 999
 };
 enum JetAlgorithm {
   kt_algorithm=0,
   cambridge_algorithm=1,
   antikt_algorithm=2, 
   genkt_algorithm=3, 
   cambridge_for_passive_algorithm=11,
   genkt_for_passive_algorithm=13, 
   ee_kt_algorithm=50,
   ee_genkt_algorithm=53,
   plugin_algorithm = 99,
   undefined_jet_algorithm = 999
 };
 typedef JetAlgorithm JetFinder;
 const JetAlgorithm aachen_algorithm = cambridge_algorithm;
 const JetAlgorithm cambridge_aachen_algorithm = cambridge_algorithm;
 enum RecombinationScheme {
   E_scheme=0,
   pt_scheme=1,
   pt2_scheme=2,
   Et_scheme=3,
   Et2_scheme=4,
   BIpt_scheme=5,
   BIpt2_scheme=6,
   WTA_pt_scheme=7,
   WTA_modp_scheme=8,
   external_scheme = 99
 };
 class ClusterSequence;
 class JetDefinition {
 public:
   class Plugin;
   class Recombiner;
   JetDefinition(JetAlgorithm jet_algorithm_in, 
                 double R_in, 
                 RecombinationScheme recomb_scheme_in = E_scheme,
                 Strategy strategy_in = Best) {
     *this = JetDefinition(jet_algorithm_in, R_in, recomb_scheme_in, strategy_in, 1);
   }
   JetDefinition(JetAlgorithm jet_algorithm_in, 
                 RecombinationScheme recomb_scheme_in = E_scheme,
                 Strategy strategy_in = Best) {
     double dummyR = 0.0;
     *this = JetDefinition(jet_algorithm_in, dummyR, recomb_scheme_in, strategy_in, 0);
   }
   JetDefinition(JetAlgorithm jet_algorithm_in, 
                 double R_in, 
                 double xtra_param_in,
                 RecombinationScheme recomb_scheme_in = E_scheme,
                 Strategy strategy_in = Best) {
     *this = JetDefinition(jet_algorithm_in, R_in, recomb_scheme_in, strategy_in, 2);
     set_extra_param(xtra_param_in);
   }
   JetDefinition(JetAlgorithm jet_algorithm_in, 
                 double R_in, 
                 const Recombiner * recombiner_in,
                 Strategy strategy_in = Best) {
     *this = JetDefinition(jet_algorithm_in, R_in, external_scheme, strategy_in);
     _recombiner = recombiner_in;
   }
   JetDefinition(JetAlgorithm jet_algorithm_in, 
                 const Recombiner * recombiner_in,
                 Strategy strategy_in = Best) {
     *this = JetDefinition(jet_algorithm_in, external_scheme, strategy_in);
     _recombiner = recombiner_in;
   }
   JetDefinition(JetAlgorithm jet_algorithm_in, 
                 double R_in, 
                 double xtra_param_in,
                 const Recombiner * recombiner_in,
                 Strategy strategy_in = Best) {
     *this = JetDefinition(jet_algorithm_in, R_in, xtra_param_in, external_scheme, strategy_in);
     _recombiner = recombiner_in;
   }
   JetDefinition()  {
     *this = JetDefinition(undefined_jet_algorithm, 1.0);
   }
   JetDefinition(const Plugin * plugin_in) {
     _plugin = plugin_in;
     _strategy = plugin_strategy;
     _Rparam = _plugin->R();
     _extra_param = 0.0; // a dummy value to keep static code checkers happy
     _jet_algorithm = plugin_algorithm;
     set_recombination_scheme(E_scheme);
   }
   JetDefinition(JetAlgorithm jet_algorithm_in, 
                 double R_in, 
                 RecombinationScheme recomb_scheme_in,
                 Strategy strategy_in,
                 int nparameters_in);
   FJCORE_DEPRECATED_MSG("This argument ordering is deprecated. Use JetDefinition(alg, R, strategy, scheme[, n_parameters]) instead",
   JetDefinition(JetAlgorithm jet_algorithm_in, 
                 double R_in, 
                 Strategy strategy_in,
                 RecombinationScheme recomb_scheme_in = E_scheme,
                 int nparameters_in = 1)){
     (*this) = JetDefinition(jet_algorithm_in,R_in,recomb_scheme_in,strategy_in,nparameters_in);
   }
   template <class L> 
   std::vector<PseudoJet> operator()(const std::vector<L> & particles) const;
   static const double max_allowable_R; //= 1000.0;
   void set_recombination_scheme(RecombinationScheme);
   void set_recombiner(const Recombiner * recomb) {
     if (_shared_recombiner) _shared_recombiner.reset(recomb);
     _recombiner = recomb;
     _default_recombiner = DefaultRecombiner(external_scheme);
   }
   void set_recombiner(const JetDefinition &other_jet_def);
   void delete_recombiner_when_unused();
   const Plugin * plugin() const {return _plugin;};
   void delete_plugin_when_unused();
   JetAlgorithm jet_algorithm  () const {return _jet_algorithm  ;}
   JetAlgorithm jet_finder     () const {return _jet_algorithm  ;}
   double    R           () const {return _Rparam      ;}
   double    extra_param () const {return _extra_param ;}
   Strategy  strategy    () const {return _strategy    ;}
   RecombinationScheme recombination_scheme() const {
     return _default_recombiner.scheme();}
   void set_jet_algorithm(JetAlgorithm njf) {_jet_algorithm = njf;}
   void set_jet_finder(JetAlgorithm njf)    {_jet_algorithm = njf;}
   void set_extra_param(double xtra_param) {_extra_param = xtra_param;}
   const Recombiner * recombiner() const {
     return _recombiner == 0 ? & _default_recombiner : _recombiner;}
   bool has_same_recombiner(const JetDefinition &other_jd) const;
   bool is_spherical() const;
   std::string description() const;
   std::string description_no_recombiner() const;
   static std::string algorithm_description(const JetAlgorithm jet_alg);
   static unsigned int n_parameters_for_algorithm(const JetAlgorithm jet_alg);
 public:
   class Recombiner {
   public:
     virtual std::string description() const = 0;
     virtual void recombine(const PseudoJet & pa, const PseudoJet & pb, 
                            PseudoJet & pab) const = 0;
     virtual void preprocess(PseudoJet & ) const {};
     virtual ~Recombiner() {};
     inline void plus_equal(PseudoJet & pa, const PseudoJet & pb) const {
       PseudoJet pres; 
       recombine(pa,pb,pres);
       pa = pres;
     }
   };
   class DefaultRecombiner : public Recombiner {
   public:
     DefaultRecombiner(RecombinationScheme recomb_scheme = E_scheme) : 
       _recomb_scheme(recomb_scheme) {}
     virtual std::string description() const FJCORE_OVERRIDE;
     virtual void recombine(const PseudoJet & pa, const PseudoJet & pb, 
                            PseudoJet & pab) const FJCORE_OVERRIDE;
     virtual void preprocess(PseudoJet & p) const FJCORE_OVERRIDE;
     RecombinationScheme scheme() const {return _recomb_scheme;}
   private:
     RecombinationScheme _recomb_scheme;
   };
   class Plugin{
   public:
     virtual std::string description() const = 0;
     virtual void run_clustering(ClusterSequence &) const = 0;
     virtual double R() const = 0;
     virtual bool supports_ghosted_passive_areas() const {return false;}
     virtual void set_ghost_separation_scale(double scale) const;
     virtual double ghost_separation_scale() const {return 0.0;}
     virtual bool exclusive_sequence_meaningful() const {return false;}
     virtual bool is_spherical() const {return false;}
     virtual ~Plugin() {};
   };
 private:
   JetAlgorithm _jet_algorithm;
   double    _Rparam;
   double    _extra_param ; ///< parameter whose meaning varies according to context
   Strategy  _strategy  ;
   const Plugin * _plugin;
   SharedPtr<const Plugin> _plugin_shared;
   DefaultRecombiner _default_recombiner;
   const Recombiner * _recombiner;
   SharedPtr<const Recombiner> _shared_recombiner;
 };
 PseudoJet join(const std::vector<PseudoJet> & pieces, const JetDefinition::Recombiner & recombiner);
 PseudoJet join(const PseudoJet & j1, 
            const JetDefinition::Recombiner & recombiner);
 PseudoJet join(const PseudoJet & j1, const PseudoJet & j2, 
            const JetDefinition::Recombiner & recombiner);
 PseudoJet join(const PseudoJet & j1, const PseudoJet & j2, const PseudoJet & j3, 
            const JetDefinition::Recombiner & recombiner);
 PseudoJet join(const PseudoJet & j1, const PseudoJet & j2, const PseudoJet & j3, const PseudoJet & j4, 
            const JetDefinition::Recombiner & recombiner);
 FJCORE_END_NAMESPACE
 #endif // __FJCORE_JETDEFINITION_HH__
 #ifndef __FJCORE_COMPOSITEJET_STRUCTURE_HH__
 #define __FJCORE_COMPOSITEJET_STRUCTURE_HH__
 FJCORE_BEGIN_NAMESPACE      // defined in fastjet/internal/base.hh
 class CompositeJetStructure : public PseudoJetStructureBase{
 public:
   CompositeJetStructure() : _area_4vector_ptr(0){};
   CompositeJetStructure(const std::vector<PseudoJet> & initial_pieces, 
             const JetDefinition::Recombiner * recombiner = 0);
   virtual ~CompositeJetStructure(){
     if (_area_4vector_ptr) delete _area_4vector_ptr;
   };
   virtual std::string description() const FJCORE_OVERRIDE;
   virtual bool has_constituents() const FJCORE_OVERRIDE;
   virtual std::vector<PseudoJet> constituents(const PseudoJet &jet) const FJCORE_OVERRIDE;
   virtual bool has_pieces(const PseudoJet & /*jet*/) const FJCORE_OVERRIDE {return true;}
   virtual std::vector<PseudoJet> pieces(const PseudoJet &jet) const FJCORE_OVERRIDE;
 protected:
   std::vector<PseudoJet> _pieces;  ///< the pieces building the jet
   PseudoJet * _area_4vector_ptr;   ///< pointer to the 4-vector jet area
 };
 template<typename T> PseudoJet join(const std::vector<PseudoJet> & pieces){
   PseudoJet result(0.0,0.0,0.0,0.0);
   for (unsigned int i=0; i<pieces.size(); i++){
     const PseudoJet it = pieces[i];
     result += it;
   }
   T *cj_struct = new T(pieces);
   result.set_structure_shared_ptr(SharedPtr<PseudoJetStructureBase>(cj_struct));
   return result;
 }
 template<typename T> PseudoJet join(const PseudoJet & j1){
   return join<T>(std::vector<PseudoJet>(1,j1));
 }
 template<typename T> PseudoJet join(const PseudoJet & j1, const PseudoJet & j2){
   std::vector<PseudoJet> pieces;
   pieces.push_back(j1);
   pieces.push_back(j2);
   return join<T>(pieces);
 }
 template<typename T> PseudoJet join(const PseudoJet & j1, const PseudoJet & j2, 
                     const PseudoJet & j3){
   std::vector<PseudoJet> pieces;
   pieces.push_back(j1);
   pieces.push_back(j2);
   pieces.push_back(j3);
   return join<T>(pieces);
 }
 template<typename T> PseudoJet join(const PseudoJet & j1, const PseudoJet & j2, 
                     const PseudoJet & j3, const PseudoJet & j4){
   std::vector<PseudoJet> pieces;
   pieces.push_back(j1);
   pieces.push_back(j2);
   pieces.push_back(j3);
   pieces.push_back(j4);
   return join<T>(pieces);
 }
 template<typename T> PseudoJet join(const std::vector<PseudoJet> & pieces, 
                     const JetDefinition::Recombiner & recombiner){
   PseudoJet result;
   if (pieces.size()>0){
     result = pieces[0];
     for (unsigned int i=1; i<pieces.size(); i++){
       recombiner.plus_equal(result, pieces[i]);
     }
   }
   T *cj_struct = new T(pieces, &recombiner);
   result.set_structure_shared_ptr(SharedPtr<PseudoJetStructureBase>(cj_struct));
   return result;
 }
 template<typename T> PseudoJet join(const PseudoJet & j1, 
                     const JetDefinition::Recombiner & recombiner){
   return join<T>(std::vector<PseudoJet>(1,j1), recombiner);
 }
 template<typename T> PseudoJet join(const PseudoJet & j1, const PseudoJet & j2, 
                     const JetDefinition::Recombiner & recombiner){
   std::vector<PseudoJet> pieces;
   pieces.reserve(2);
   pieces.push_back(j1);
   pieces.push_back(j2);
   return join<T>(pieces, recombiner);
 }
 template<typename T> PseudoJet join(const PseudoJet & j1, const PseudoJet & j2, 
                     const PseudoJet & j3, 
                     const JetDefinition::Recombiner & recombiner){
   std::vector<PseudoJet> pieces;
   pieces.reserve(3);
   pieces.push_back(j1);
   pieces.push_back(j2);
   pieces.push_back(j3);
   return join<T>(pieces, recombiner);
 }
 template<typename T> PseudoJet join(const PseudoJet & j1, const PseudoJet & j2, 
                     const PseudoJet & j3, const PseudoJet & j4, 
                     const JetDefinition::Recombiner & recombiner){
   std::vector<PseudoJet> pieces;
   pieces.reserve(4);
   pieces.push_back(j1);
   pieces.push_back(j2);
   pieces.push_back(j3);
   pieces.push_back(j4);
   return join<T>(pieces, recombiner);
 }
 FJCORE_END_NAMESPACE      // defined in fastjet/internal/base.hh
 #endif // __FJCORE_MERGEDJET_STRUCTURE_HH__
 #ifndef __FJCORE_CLUSTER_SEQUENCE_STRUCTURE_HH__
 #define __FJCORE_CLUSTER_SEQUENCE_STRUCTURE_HH__
 #include <vector>
 FJCORE_BEGIN_NAMESPACE      // defined in fastjet/internal/base.hh
 class ClusterSequenceStructure : public PseudoJetStructureBase{
 public:
   ClusterSequenceStructure() : _associated_cs(NULL){}
   ClusterSequenceStructure(const ClusterSequence *cs){
     set_associated_cs(cs);
   };
   virtual ~ClusterSequenceStructure();
   virtual std::string description() const FJCORE_OVERRIDE{
     return "PseudoJet with an associated ClusterSequence";
   }
   virtual bool has_associated_cluster_sequence() const FJCORE_OVERRIDE{ return true;}
   virtual const ClusterSequence* associated_cluster_sequence() const FJCORE_OVERRIDE;
   virtual bool has_valid_cluster_sequence() const FJCORE_OVERRIDE;
   virtual const ClusterSequence * validated_cs() const FJCORE_OVERRIDE;
   virtual void set_associated_cs(const ClusterSequence * new_cs){
     _associated_cs = new_cs;
   }
   virtual bool has_partner(const PseudoJet &reference, PseudoJet &partner) const FJCORE_OVERRIDE;
   virtual bool has_child(const PseudoJet &reference, PseudoJet &child) const FJCORE_OVERRIDE;
   virtual bool has_parents(const PseudoJet &reference, PseudoJet &parent1, PseudoJet &parent2) const FJCORE_OVERRIDE;
   virtual bool object_in_jet(const PseudoJet &reference, const PseudoJet &jet) const FJCORE_OVERRIDE;
   virtual bool has_constituents() const FJCORE_OVERRIDE;
   virtual std::vector<PseudoJet> constituents(const PseudoJet &reference) const FJCORE_OVERRIDE;
   virtual bool has_exclusive_subjets() const FJCORE_OVERRIDE;
   virtual std::vector<PseudoJet> exclusive_subjets(const PseudoJet &reference, const double & dcut) const FJCORE_OVERRIDE;
   virtual int n_exclusive_subjets(const PseudoJet &reference, const double & dcut) const FJCORE_OVERRIDE;
   virtual std::vector<PseudoJet> exclusive_subjets_up_to (const PseudoJet &reference, int nsub) const FJCORE_OVERRIDE;
   virtual double exclusive_subdmerge(const PseudoJet &reference, int nsub) const FJCORE_OVERRIDE;
   virtual double exclusive_subdmerge_max(const PseudoJet &reference, int nsub) const FJCORE_OVERRIDE;
   virtual bool has_pieces(const PseudoJet &reference) const FJCORE_OVERRIDE;
   virtual std::vector<PseudoJet> pieces(const PseudoJet &reference) const FJCORE_OVERRIDE;
 protected:
   const ClusterSequence *_associated_cs;
 };
 FJCORE_END_NAMESPACE
 #endif  //  __FJCORE_CLUSTER_SEQUENCE_STRUCTURE_HH__
 #ifndef __FJCORE_CLUSTERSEQUENCE_HH__
 #define __FJCORE_CLUSTERSEQUENCE_HH__
 #include<vector>
 #include<map>
 #include<memory>
 #include<cassert>
 #include<iostream>
 #include<string>
 #include<set>
 #include<cmath> // needed to get double std::abs(double)
 FJCORE_BEGIN_NAMESPACE      // defined in fastjet/internal/base.hh
 class ClusterSequenceStructure;
 class DynamicNearestNeighbours;
 class ClusterSequence {
  public: 
   ClusterSequence () : _deletes_self_when_unused(false) {}
   template<class L> ClusterSequence (
                       const std::vector<L> & pseudojets,
                   const JetDefinition & jet_def,
                   const bool & writeout_combinations = false);
   ClusterSequence (const ClusterSequence & cs) : _deletes_self_when_unused(false) {
     transfer_from_sequence(cs);
   }
   ClusterSequence & operator=(const ClusterSequence & cs);
   virtual ~ClusterSequence (); //{}
   std::vector<PseudoJet> inclusive_jets (const double ptmin = 0.0) const;
   int n_exclusive_jets (const double dcut) const;
   std::vector<PseudoJet> exclusive_jets (const double dcut) const;
   std::vector<PseudoJet> exclusive_jets (const int njets) const;
   std::vector<PseudoJet> exclusive_jets_up_to (const int njets) const;
   double exclusive_dmerge (const int njets) const;
   double exclusive_dmerge_max (const int njets) const;
   double exclusive_ymerge (int njets) const {return exclusive_dmerge(njets) / Q2();}
   double exclusive_ymerge_max (int njets) const {return exclusive_dmerge_max(njets)/Q2();}
   int n_exclusive_jets_ycut (double ycut) const {return n_exclusive_jets(ycut*Q2());}
   std::vector<PseudoJet> exclusive_jets_ycut (double ycut) const {
     int njets = n_exclusive_jets_ycut(ycut);
     return exclusive_jets(njets);
   }
   std::vector<PseudoJet> exclusive_subjets (const PseudoJet & jet, 
                                             const double dcut) const;
   int n_exclusive_subjets(const PseudoJet & jet, 
                           const double dcut) const;
   std::vector<PseudoJet> exclusive_subjets (const PseudoJet & jet, 
                                             int nsub) const;
   std::vector<PseudoJet> exclusive_subjets_up_to (const PseudoJet & jet, 
                           int nsub) const;
   double exclusive_subdmerge(const PseudoJet & jet, int nsub) const;
   double exclusive_subdmerge_max(const PseudoJet & jet, int nsub) const;
   double Q() const {return _Qtot;}
   double Q2() const {return _Qtot*_Qtot;}
   bool object_in_jet(const PseudoJet & object, const PseudoJet & jet) const;
   bool has_parents(const PseudoJet & jet, PseudoJet & parent1, 
                PseudoJet & parent2) const;
   bool has_child(const PseudoJet & jet, PseudoJet & child) const;
   bool has_child(const PseudoJet & jet, const PseudoJet * & childp) const;
   bool has_partner(const PseudoJet & jet, PseudoJet & partner) const;
   std::vector<PseudoJet> constituents (const PseudoJet & jet) const;
   void print_jets_for_root(const std::vector<PseudoJet> & jets, 
                            std::ostream & ostr = std::cout) const;
   void print_jets_for_root(const std::vector<PseudoJet> & jets, 
                            const std::string & filename,
                const std::string & comment = "") const;
   void add_constituents (const PseudoJet & jet, 
              std::vector<PseudoJet> & subjet_vector) const;
   inline Strategy strategy_used () const {return _strategy;}
   std::string strategy_string () const {return strategy_string(_strategy);}
   std::string strategy_string (Strategy strategy_in) const;
   const JetDefinition & jet_def() const {return _jet_def;}
   void delete_self_when_unused();
   bool will_delete_self_when_unused() const {return _deletes_self_when_unused;}
   void signal_imminent_self_deletion() const;
   double jet_scale_for_algorithm(const PseudoJet & jet) const;
   void plugin_record_ij_recombination(int jet_i, int jet_j, double dij, 
                       int & newjet_k) {
     assert(plugin_activated());
     _do_ij_recombination_step(jet_i, jet_j, dij, newjet_k);
   }
   void plugin_record_ij_recombination(int jet_i, int jet_j, double dij, 
                       const PseudoJet & newjet, 
                       int & newjet_k);
   void plugin_record_iB_recombination(int jet_i, double diB) {
     assert(plugin_activated());
     _do_iB_recombination_step(jet_i, diB);
   }
   class Extras {
   public:
     virtual ~Extras() {}
     virtual std::string description() const {return "This is a dummy extras class that contains no extra information! Derive from it if you want to use it to provide extra information from a plugin jet finder";}
   };
   inline void plugin_associate_extras(Extras * extras_in) {
     _extras.reset(extras_in);
   }
 #ifndef SWIG
 #ifdef FJCORE_HAVE_AUTO_PTR_INTERFACE
   FJCORE_DEPRECATED_MSG("Please use ClusterSequence::plugin_associate_extras(Extras * extras_in)) instead",
   inline void plugin_associate_extras(std::auto_ptr<Extras> extras_in)){
     _extras.reset(extras_in.release());
   }
 #endif
 #endif //SWIG
   inline bool plugin_activated() const {return _plugin_activated;}
   const Extras * extras() const {return _extras.get();}
   template<class GBJ> void plugin_simple_N2_cluster () {
     assert(plugin_activated());
     _simple_N2_cluster<GBJ>();
   }
 public:
   struct history_element{
     int parent1; /// index in _history where first parent of this jet
     int parent2; /// index in _history where second parent of this jet
     int child;   /// index in _history where the current jet is
          /// recombined with another jet to form its child. It
          /// is Invalid if this jet does not further
          /// recombine.
     int jetp_index; /// index in the _jets vector where we will find the
     double dij;  /// the distance corresponding to the recombination
          /// at this stage of the clustering.
     double max_dij_so_far; /// the largest recombination distance seen
                /// so far in the clustering history.
   };
   enum JetType {Invalid=-3, InexistentParent = -2, BeamJet = -1};
   const std::vector<PseudoJet> & jets()    const;
   const std::vector<history_element> & history() const;
   unsigned int n_particles() const;
   std::vector<int> particle_jet_indices(const std::vector<PseudoJet> &) const;
   std::vector<int> unique_history_order() const;
   std::vector<PseudoJet> unclustered_particles() const;
   std::vector<PseudoJet> childless_pseudojets() const;
   bool contains(const PseudoJet & object) const;
   void transfer_from_sequence(const ClusterSequence & from_seq,
                   const FunctionOfPseudoJet<PseudoJet> * action_on_jets = 0);
   const SharedPtr<PseudoJetStructureBase> & structure_shared_ptr() const{
     return _structure_shared_ptr;
   }
   typedef ClusterSequenceStructure StructureType;
   static void print_banner();
   static void set_fastjet_banner_stream(std::ostream * ostr) {_fastjet_banner_ostr = ostr;}
   static std::ostream * fastjet_banner_stream() {return _fastjet_banner_ostr;}
 private:
 #ifdef FJCORE_HAVE_LIMITED_THREAD_SAFETY
   static std::atomic<std::ostream*> _fastjet_banner_ostr;
 #else
   static std::ostream * _fastjet_banner_ostr;
 #endif // FJCORE_HAVE_LIMITED_THREAD_SAFETY
 protected:
   JetDefinition _jet_def;
   template<class L> void _transfer_input_jets(
                                      const std::vector<L> & pseudojets);
   void _initialise_and_run (const JetDefinition & jet_def,
                 const bool & writeout_combinations);
   void _initialise_and_run_no_decant();
   void _decant_options(const JetDefinition & jet_def,
                        const bool & writeout_combinations);
   void _decant_options_partial();
   void _fill_initial_history();
   void _do_ij_recombination_step(const int jet_i, const int jet_j, 
                  const double dij, int & newjet_k);
   void _do_iB_recombination_step(const int jet_i, const double diB);
   void _set_structure_shared_ptr(PseudoJet & j);
   void _update_structure_use_count();
   Strategy _best_strategy() const;
   class _Parabola {
   public:
     _Parabola(double a, double b, double c) : _a(a), _b(b), _c(c) {}
     inline double operator()(const double R) const {return _c*(_a*R*R + _b*R + 1);}
   private:
     double _a, _b, _c;
   };
   class _Line {
   public:
     _Line(double a, double b) : _a(a), _b(b) {}
     inline double operator()(const double R) const {return _a*R + _b;}
   private:
     double _a, _b;
   };
   std::vector<PseudoJet> _jets;
   std::vector<history_element> _history;
   void get_subhist_set(std::set<const history_element*> & subhist,
                        const  PseudoJet & jet, double dcut, int maxjet) const;
   bool _writeout_combinations;
   int  _initial_n;
   double _Rparam, _R2, _invR2;
   double _Qtot;
   Strategy    _strategy;
   JetAlgorithm  _jet_algorithm;
   SharedPtr<PseudoJetStructureBase> _structure_shared_ptr; //< will actually be of type ClusterSequenceStructure
   int _structure_use_count_after_construction; //< info of use when CS handles its own memory
 #ifdef FJCORE_HAVE_THREAD_SAFETY
   mutable std::atomic<bool> _deletes_self_when_unused;
 #else
   mutable bool _deletes_self_when_unused;
 #endif
  private:
   bool _plugin_activated;
   SharedPtr<Extras> _extras; // things the plugin might want to add
   void _really_dumb_cluster ();
   void _delaunay_cluster ();
   template<class BJ> void _simple_N2_cluster ();
   void _tiled_N2_cluster ();
   void _faster_tiled_N2_cluster ();
   void _minheap_faster_tiled_N2_cluster();
   void _CP2DChan_cluster();
   void _CP2DChan_cluster_2pi2R ();
   void _CP2DChan_cluster_2piMultD ();
   void _CP2DChan_limited_cluster(double D);
   void _do_Cambridge_inclusive_jets();
   void _fast_NsqrtN_cluster();
   void _add_step_to_history( //const int step_number,
                             const int parent1, 
                 const int parent2, const int jetp_index,
                 const double dij);
   void _extract_tree_children(int pos, std::valarray<bool> &, 
         const std::valarray<int> &, std::vector<int> &) const;
   void _extract_tree_parents (int pos, std::valarray<bool> &, 
                 const std::valarray<int> &,  std::vector<int> &) const;
   typedef std::pair<int,int> TwoVertices;
   typedef std::pair<double,TwoVertices> DijEntry;
   typedef std::multimap<double,TwoVertices> DistMap;
   void _add_ktdistance_to_map(const int ii, 
                   DistMap & DijMap,
                   const DynamicNearestNeighbours * DNN);
   static thread_safety_helpers::FirstTimeTrue _first_time;
   static LimitedWarning _exclusive_warnings;
   static LimitedWarning _changed_strategy_warning;
   struct BriefJet {
     double     eta, phi, kt2, NN_dist;
     BriefJet * NN;
     int        _jets_index;
   };
   class TiledJet {
   public:
     double     eta, phi, kt2, NN_dist;
     TiledJet * NN, *previous, * next; 
     int        _jets_index, tile_index, diJ_posn;
     inline void label_minheap_update_needed() {diJ_posn = 1;}
     inline void label_minheap_update_done()   {diJ_posn = 0;}
     inline bool minheap_update_needed() const {return diJ_posn==1;}
   };
   template <class J> void _bj_set_jetinfo( J * const jet, 
                          const int _jets_index) const;
   void _bj_remove_from_tiles( TiledJet * const jet) const;
   template <class J> double _bj_dist(const J * const jeta, 
             const J * const jetb) const;
   template <class J> double _bj_diJ(const J * const jeta) const;
   template <class J> inline J * _bj_of_hindex(
                           const int hist_index, 
               J * const head, J * const tail) 
     const {
     J * res;
     for(res = head; res<tail; res++) {
       if (_jets[res->_jets_index].cluster_hist_index() == hist_index) {break;}
     }
     return res;
   }
   template <class J> void _bj_set_NN_nocross(J * const jeta, 
             J * const head, const J * const tail) const;
   template <class J> void _bj_set_NN_crosscheck(J * const jeta, 
             J * const head, const J * const tail) const;
   static const int n_tile_neighbours = 9;
   struct Tile {
     Tile *   begin_tiles[n_tile_neighbours]; 
     Tile **  surrounding_tiles; 
     Tile **  RH_tiles;  
     Tile **  end_tiles; 
     TiledJet * head;    
     bool     tagged;    
   };
   std::vector<Tile> _tiles;
   double _tiles_eta_min, _tiles_eta_max;
   double _tile_size_eta, _tile_size_phi;
   int    _n_tiles_phi,_tiles_ieta_min,_tiles_ieta_max;
   inline int _tile_index (int ieta, int iphi) const {
     return (ieta-_tiles_ieta_min)*_n_tiles_phi
                   + (iphi+_n_tiles_phi) % _n_tiles_phi;
   }
   int  _tile_index(const double eta, const double phi) const;
   void _tj_set_jetinfo ( TiledJet * const jet, const int _jets_index);
   void  _bj_remove_from_tiles(TiledJet * const jet);
   void _initialise_tiles();
   void _print_tiles(TiledJet * briefjets ) const;
   void _add_neighbours_to_tile_union(const int tile_index, 
          std::vector<int> & tile_union, int & n_near_tiles) const;
   void _add_untagged_neighbours_to_tile_union(const int tile_index, 
          std::vector<int> & tile_union, int & n_near_tiles);
   struct EEBriefJet {
     double NN_dist;  // obligatorily present
     double kt2;      // obligatorily present == E^2 in general
     EEBriefJet * NN; // must be present too
     int    _jets_index; // must also be present!
     double nx, ny, nz;  // our internal storage for fast distance calcs
   };
   void _simple_N2_cluster_BriefJet();
   void _simple_N2_cluster_EEBriefJet();
 };
 template<class L> void ClusterSequence::_transfer_input_jets(
                                        const std::vector<L> & pseudojets) {
   _jets.reserve(pseudojets.size()*2);
   for (unsigned int i = 0; i < pseudojets.size(); i++) {
     _jets.push_back(pseudojets[i]);}
 }
 template<class L> ClusterSequence::ClusterSequence (
                       const std::vector<L> & pseudojets,
                   const JetDefinition & jet_def_in,
                   const bool & writeout_combinations) :
   _jet_def(jet_def_in), _writeout_combinations(writeout_combinations),
   _structure_shared_ptr(new ClusterSequenceStructure(this))
 {
   _transfer_input_jets(pseudojets);
   _decant_options_partial();
   _initialise_and_run_no_decant();
 }
 inline const std::vector<PseudoJet> & ClusterSequence::jets () const {
   return _jets;
 }
 inline const std::vector<ClusterSequence::history_element> & ClusterSequence::history () const {
   return _history;
 }
 inline unsigned int ClusterSequence::n_particles() const {return _initial_n;}
 #ifndef __CINT__
 template<class L>
 std::vector<PseudoJet> JetDefinition::operator()(const std::vector<L> & particles) const {
   ClusterSequence * cs = new ClusterSequence(particles, *this);
   std::vector<PseudoJet> jets;
   if (is_spherical()) {
     jets = sorted_by_E(cs->inclusive_jets());
   } else {
     jets = sorted_by_pt(cs->inclusive_jets());
   }
   if (jets.size() != 0) {
     cs->delete_self_when_unused();
   } else {
     delete cs;
   }
   return jets;
 }
 #endif // __CINT__
 template <class J> inline void ClusterSequence::_bj_set_jetinfo(
                             J * const jetA, const int _jets_index) const {
     jetA->eta  = _jets[_jets_index].rap();
     jetA->phi  = _jets[_jets_index].phi_02pi();
     jetA->kt2  = jet_scale_for_algorithm(_jets[_jets_index]);
     jetA->_jets_index = _jets_index;
     jetA->NN_dist = _R2;
     jetA->NN      = NULL;
 }
 template <class J> inline double ClusterSequence::_bj_dist(
                 const J * const jetA, const J * const jetB) const {
 #ifndef FJCORE_NEW_DELTA_PHI
   double dphi = std::abs(jetA->phi - jetB->phi);
   double deta = (jetA->eta - jetB->eta);
   if (dphi > pi) {dphi = twopi - dphi;}
 #else 
   double dphi = pi-std::abs(pi-std::abs(jetA->phi - jetB->phi));
   double deta = (jetA->eta - jetB->eta);
 #endif 
   return dphi*dphi + deta*deta;
 }
 template <class J> inline double ClusterSequence::_bj_diJ(const J * const jet) const {
   double kt2 = jet->kt2;
   if (jet->NN != NULL) {if (jet->NN->kt2 < kt2) {kt2 = jet->NN->kt2;}}
   return jet->NN_dist * kt2;
 }
 template <class J> inline void ClusterSequence::_bj_set_NN_nocross(
                  J * const jet, J * const head, const J * const tail) const {
   double NN_dist = _R2;
   J * NN  = NULL;
   if (head < jet) {
     for (J * jetB = head; jetB != jet; jetB++) {
       double dist = _bj_dist(jet,jetB);
       if (dist < NN_dist) {
     NN_dist = dist;
     NN = jetB;
       }
     }
   }
   if (tail > jet) {
     for (J * jetB = jet+1; jetB != tail; jetB++) {
       double dist = _bj_dist(jet,jetB);
       if (dist < NN_dist) {
     NN_dist = dist;
     NN = jetB;
       }
     }
   }
   jet->NN = NN;
   jet->NN_dist = NN_dist;
 }
 template <class J> inline void ClusterSequence::_bj_set_NN_crosscheck(J * const jet, 
             J * const head, const J * const tail) const {
   double NN_dist = _R2;
   J * NN  = NULL;
   for (J * jetB = head; jetB != tail; jetB++) {
     double dist = _bj_dist(jet,jetB);
     if (dist < NN_dist) {
       NN_dist = dist;
       NN = jetB;
     }
     if (dist < jetB->NN_dist) {
       jetB->NN_dist = dist;
       jetB->NN = jet;
     }
   }
   jet->NN = NN;
   jet->NN_dist = NN_dist;
 }
 FJCORE_END_NAMESPACE
 #endif // __FJCORE_CLUSTERSEQUENCE_HH__
 #ifndef __FJCORE_NNBASE_HH__
 #define __FJCORE_NNBASE_HH__
 FJCORE_BEGIN_NAMESPACE      // defined in fastjet/internal/base.hh
 class _NoInfo {};
 template<class I> class NNInfo {
 public:
   NNInfo()         : _info(NULL) {}
   NNInfo(I * info) : _info(info) {}
   template<class BJ> void init_jet(BJ * briefjet, const fjcore::PseudoJet & jet, int index) { briefjet->init(jet, index, _info);}
 private:
   I * _info;
 };
 template<> class NNInfo<_NoInfo>  {
 public:
   NNInfo()           {}
   NNInfo(_NoInfo * ) {}
   template<class BJ> void init_jet(BJ * briefjet, const fjcore::PseudoJet & jet, int index) { briefjet->init(jet, index);}
 };
 template<class I = _NoInfo> class NNBase : public NNInfo<I> {
 public:
   NNBase() {}
   NNBase(I * info) : NNInfo<I>(info) {}
   virtual void start(const std::vector<PseudoJet> & jets) = 0;
   virtual double dij_min(int & iA, int & iB) = 0;
   virtual void remove_jet(int iA) = 0;
   virtual void merge_jets(int iA, int iB, const PseudoJet & jet, int jet_index) =  0;
   virtual ~NNBase() {};
 };
 FJCORE_END_NAMESPACE      // defined in fastjet/internal/base.hh
 #endif // __FJCORE_NNBASE_HH__
 #ifndef __FJCORE_NNH_HH__
 #define __FJCORE_NNH_HH__
 FJCORE_BEGIN_NAMESPACE      // defined in fastjet/internal/base.hh
 template<class BJ, class I = _NoInfo> class NNH : public NNBase<I> {
 public:
   NNH(const std::vector<PseudoJet> & jets)           : NNBase<I>()     {start(jets);}
   NNH(const std::vector<PseudoJet> & jets, I * info) : NNBase<I>(info) {start(jets);}
   void start(const std::vector<PseudoJet> & jets);
   double dij_min(int & iA, int & iB);
   void remove_jet(int iA);
   void merge_jets(int iA, int iB, const PseudoJet & jet, int jet_index);
   ~NNH() {
     delete[] briefjets;
   }
 private:
   class NNBJ; // forward declaration
   void set_NN_crosscheck(NNBJ * jet, NNBJ * begin, NNBJ * end);
   void set_NN_nocross   (NNBJ * jet, NNBJ * begin, NNBJ * end);
   NNBJ * briefjets;
   NNBJ * head, * tail;
   int n;
   std::vector<NNBJ *> where_is;
   class NNBJ : public BJ {
   public:
     void init(const PseudoJet & jet, int index_in) {
       BJ::init(jet);
       other_init(index_in);
     }
     void init(const PseudoJet & jet, int index_in, I * info) {
       BJ::init(jet, info);
       other_init(index_in);
     }
     void other_init(int index_in) {
       _index = index_in;
       NN_dist = BJ::beam_distance();
       NN = NULL;
     }
     int index() const {return _index;}
     double NN_dist;
     NNBJ * NN;
   private:
     int _index;
   };
 };
 template<class BJ, class I> void NNH<BJ,I>::start(const std::vector<PseudoJet> & jets) {
   n = jets.size();
   briefjets = new NNBJ[n];
   where_is.resize(2*n);
   NNBJ * jetA = briefjets;
   for (int i = 0; i< n; i++) {
     this->init_jet(jetA, jets[i], i);
     where_is[i] = jetA;
     jetA++; // move on to next entry of briefjets
   }
   tail = jetA; // a semaphore for the end of briefjets
   head = briefjets; // a nicer way of naming start
   for (jetA = head + 1; jetA != tail; jetA++) {
     set_NN_crosscheck(jetA, head, jetA);
   }
 }
 template<class BJ, class I> double NNH<BJ,I>::dij_min(int & iA, int & iB) {
   double diJ_min = briefjets[0].NN_dist;
   int diJ_min_jet = 0;
   for (int i = 1; i < n; i++) {
     if (briefjets[i].NN_dist < diJ_min) {
       diJ_min_jet = i; 
       diJ_min  = briefjets[i].NN_dist;
     }
   }
   NNBJ * jetA = & briefjets[diJ_min_jet];
   iA = jetA->index();
   iB = jetA->NN ? jetA->NN->index() : -1;
   return diJ_min;
 }
 template<class BJ, class I> void NNH<BJ,I>::remove_jet(int iA) {
   NNBJ * jetA = where_is[iA];
   tail--; n--;
   *jetA = *tail;
   where_is[jetA->index()] = jetA;
   for (NNBJ * jetI = head; jetI != tail; jetI++) {
     if (jetI->NN == jetA) set_NN_nocross(jetI, head, tail);
     if (jetI->NN == tail) {jetI->NN = jetA;}
   }
 }
 template<class BJ, class I> void NNH<BJ,I>::merge_jets(int iA, int iB, 
                     const PseudoJet & jet, int index) {
   NNBJ * jetA = where_is[iA];
   NNBJ * jetB = where_is[iB];
   if (jetA < jetB) std::swap(jetA,jetB);
   this->init_jet(jetB, jet, index);
   if (index >= int(where_is.size())) where_is.resize(2*index);
   where_is[jetB->index()] = jetB;
   tail--; n--;
   *jetA = *tail;
   where_is[jetA->index()] = jetA;
   for (NNBJ * jetI = head; jetI != tail; jetI++) {
     if (jetI->NN == jetA || jetI->NN == jetB) {
       set_NN_nocross(jetI, head, tail);
     } 
     double dist = jetI->distance(jetB);
     if (dist < jetI->NN_dist) {
       if (jetI != jetB) {
     jetI->NN_dist = dist;
     jetI->NN = jetB;
       }
     }
     if (dist < jetB->NN_dist) {
       if (jetI != jetB) {
     jetB->NN_dist = dist;
     jetB->NN      = jetI;
       }
     }
     if (jetI->NN == tail) {jetI->NN = jetA;}
   }
 }
 template <class BJ, class I> void NNH<BJ,I>::set_NN_crosscheck(NNBJ * jet, 
             NNBJ * begin, NNBJ * end) {
   double NN_dist = jet->beam_distance();
   NNBJ * NN      = NULL;
   for (NNBJ * jetB = begin; jetB != end; jetB++) {
     double dist = jet->distance(jetB);
     if (dist < NN_dist) {
       NN_dist = dist;
       NN = jetB;
     }
     if (dist < jetB->NN_dist) {
       jetB->NN_dist = dist;
       jetB->NN = jet;
     }
   }
   jet->NN = NN;
   jet->NN_dist = NN_dist;
 }
 template <class BJ, class I>  void NNH<BJ,I>::set_NN_nocross(
                  NNBJ * jet, NNBJ * begin, NNBJ * end) {
   double NN_dist = jet->beam_distance();
   NNBJ * NN      = NULL;
   if (begin < jet) {
     for (NNBJ * jetB = begin; jetB != jet; jetB++) {
       double dist = jet->distance(jetB);
       if (dist < NN_dist) {
     NN_dist = dist;
     NN = jetB;
       }
     }
   }
   if (end > jet) {
     for (NNBJ * jetB = jet+1; jetB != end; jetB++) {
       double dist = jet->distance (jetB);
       if (dist < NN_dist) {
     NN_dist = dist;
     NN = jetB;
       }
     }
   }
   jet->NN = NN;
   jet->NN_dist = NN_dist;
 }
 FJCORE_END_NAMESPACE      // defined in fastjet/internal/base.hh
 #endif // __FJCORE_NNH_HH__
 #endif