FastJet  3.4.0
FunctionOfPseudoJet.hh
1 #ifndef __FASTJET_FUNCTION_OF_PSEUDOJET_HH__
2 #define __FASTJET_FUNCTION_OF_PSEUDOJET_HH__
3 
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33 
34 #include "fastjet/PseudoJet.hh"
35 #include "fastjet/Selector.hh"
36 
37 FASTJET_BEGIN_NAMESPACE
38 
39 /// \class FunctionOfPseudoJet
40 /// base class providing interface for a generic function of a PseudoJet
41 ///
42 /// This class serves as a base class to provide a standard interface
43 /// for a function that returns an object of a given (templated) type
44 /// that depends on a PseudoJet argument. The rationale for using a
45 /// class (rather than a pointer to a function) is that a class can be
46 /// constructed with (and store) additional arguments.
47 template<typename TOut>
49 public:
50  /// default ctor
52 
53  // ctor that creates a constant function
54  //----------
55  // this declaration was present in versions of FJ from 3.0.0 to 3.0.6,
56  // but never implemented. It is being removed from 3.0.7 upwards
57  // to avoid misleading users
58  //FunctionOfPseudoJet(const TOut &constant_value);
59 
60  /// default dtor (virtual to allow safe polymorphism)
62 
63  /// returns a description of the function (an empty string by
64  /// default)
65  virtual std::string description() const{ return "";}
66 
67  /// the action of the function
68  /// this _has_ to be overloaded in derived classes
69  /// \param pj the PseudoJet input to the function
70  virtual TOut result(const PseudoJet &pj) const = 0;
71 
72  /// apply the function using the "traditional" () operator.
73  /// By default, this just calls the apply(...) method above.
74  /// \param pj the PseudoJet input to the function
75  TOut operator()(const PseudoJet &pj) const { return result(pj);}
76 
77  /// apply the function on a vector of PseudoJet, returning a vector
78  /// of the results.
79  /// This just calls apply on every PseudoJet in the vector.
80  /// \param pjs the vector of PseudoJet inputs to the function
81  std::vector<TOut> operator()(const std::vector<PseudoJet> &pjs) const {
82  std::vector<TOut> res(pjs.size());
83  for (unsigned int i=0; i<pjs.size(); i++)
84  res[i] = result(pjs[i]);
85  return res;
86  }
87 };
88 
89 // The following functions will not be for FJ3.0, because passing a
90 // reference does not work when the argument is a temporary, which can
91 // lead to hard-to-diagnose run-time errors. A workaround is to to
92 // have a pointer rather than a reference as argument, since this
93 // provides a clearer signal to the user that the object must remain
94 // in scope.
95 //
96 //
97 // // Selectors created from the ordering between a FunctionOfPseudoJet
98 // // and a constant
99 // //----------------------------------------------------------------------
100 //
101 // /// 'larger than' operator
102 // ///
103 // /// Select jets for which the given function returns a result larger
104 // /// than the specified constant
105 // Selector operator >(const FunctionOfPseudoJet<double> & fn, const double & cut);
106 //
107 // /// 'smaller than' operator
108 // ///
109 // /// Select jets for which the given function returns a result smaller
110 // /// than the specified constant
111 // Selector operator <(const FunctionOfPseudoJet<double> & fn, const double & cut);
112 //
113 // /// 'larger or equal' operator
114 // ///
115 // /// Select jets for which the given function returns a result larger or equal
116 // /// to the specified constant
117 // Selector operator >=(const FunctionOfPseudoJet<double> & fn, const double & cut);
118 //
119 // /// 'smaller or equal' operator
120 // ///
121 // /// Select jets for which the given function returns a result smaller or equal
122 // /// to the specified constant
123 // Selector operator <=(const FunctionOfPseudoJet<double> & fn, const double & cut);
124 
125 
126 FASTJET_END_NAMESPACE
127 
128 #endif // __FASTJET_FUNCTION_OF_PSEUDOJET_HH__
base class providing interface for a generic function of a PseudoJet
TOut operator()(const PseudoJet &pj) const
apply the function using the "traditional" () operator.
std::vector< TOut > operator()(const std::vector< PseudoJet > &pjs) const
apply the function on a vector of PseudoJet, returning a vector of the results.
virtual std::string description() const
returns a description of the function (an empty string by default)
virtual TOut result(const PseudoJet &pj) const =0
the action of the function this has to be overloaded in derived classes
virtual ~FunctionOfPseudoJet()
default dtor (virtual to allow safe polymorphism)
Class to contain pseudojets, including minimal information of use to jet-clustering routines.
Definition: PseudoJet.hh:68