include/EvtGenBase/EvtAmplitude.hh

0001
0002 /***********************************************************************
0003 * Copyright 1998-2020 CERN for the benefit of the EvtGen authors       *
0004 *                                                                      *
0005 * This file is part of EvtGen.                                         *
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0020
0021 #ifndef EVT_AMPLITUDE_HH
0022 #define EVT_AMPLITUDE_HH
0023
0024 #include "EvtGenBase/EvtComplex.hh"
0025
0026 // Complex-valued amplitude
0027
0028 template <class T>
0029 class EvtAmplitude {
0030   public:
0031     EvtAmplitude() = default;
0032     EvtAmplitude( const EvtAmplitude& ) = default;
0033     EvtAmplitude( EvtAmplitude&& ) = default;
0034     EvtAmplitude& operator=( const EvtAmplitude& ) = default;
0035     EvtAmplitude& operator=( EvtAmplitude&& ) = default;
0036     virtual ~EvtAmplitude() = default;
0037
0038     virtual EvtAmplitude<T>* clone() const = 0;
0039
0040     EvtComplex evaluate( const T& p ) const
0041     {
0042         EvtComplex ret( 0., 0. );
0043         if ( p.isValid() )
0044             ret = amplitude( p );
0045         return ret;
0046     }
0047
0048   protected:
0049     // Derive in subclasses to define amplitude computation
0050     // for a fully constructed amplitude object.
0051
0052     virtual EvtComplex amplitude( const T& ) const = 0;
0053 };
0054
0055 #endif