EvtSpinAmp.hh

Go to the documentation of this file.

/***********************************************************************
* Copyright 1998-2020 CERN for the benefit of the EvtGen authors       *
*                                                                      *
* This file is part of EvtGen.                                         *
*                                                                      *
* EvtGen 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 3 of the License, or    *
* (at your option) any later version.                                  *
*                                                                      *
* EvtGen 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 EvtGen.  If not, see <https://www.gnu.org/licenses/>.     *
***********************************************************************/

#ifndef __EVTSPINAMP_HH__
#define __EVTSPINAMP_HH__

#include "EvtGenBase/EvtComplex.hh"
#include "EvtGenBase/EvtSpinType.hh"

#include <vector>
using std::vector;

#include <cstdarg>

class EvtSpinAmp;
EvtSpinAmp operator*( const EvtComplex&, const EvtSpinAmp& );
EvtSpinAmp operator*( const EvtSpinAmp&, const EvtComplex& );
EvtSpinAmp operator/( const EvtSpinAmp&, const EvtComplex& );

class EvtSpinAmp {
    friend EvtSpinAmp operator*( const EvtComplex&, const EvtSpinAmp& );
    friend EvtSpinAmp operator*( const EvtSpinAmp&, const EvtComplex& );
    friend EvtSpinAmp operator/( const EvtSpinAmp&, const EvtComplex& );
    friend std::ostream& operator<<( std::ostream&, const EvtSpinAmp& );

  public:
    EvtSpinAmp(){};
    EvtSpinAmp( const vector<EvtSpinType::spintype>& );
    EvtSpinAmp( const vector<EvtSpinType::spintype>&, const EvtComplex& );
    EvtSpinAmp( const vector<EvtSpinType::spintype>&, const vector<EvtComplex>& );
    EvtSpinAmp( const EvtSpinAmp& );

    ~EvtSpinAmp(){};

    // Input to the index functions are twice the magnetic quantum number
    EvtComplex& operator()( const vector<int>& );
    const EvtComplex& operator()( const vector<int>& ) const;
    EvtComplex& operator()( int, ... );
    const EvtComplex& operator()( int, ... ) const;

    EvtSpinAmp& operator=( const EvtSpinAmp& );

    EvtSpinAmp operator+( const EvtSpinAmp& ) const;
    EvtSpinAmp& operator+=( const EvtSpinAmp& );

    EvtSpinAmp operator-( const EvtSpinAmp& ) const;
    EvtSpinAmp& operator-=( const EvtSpinAmp& );

    // Direct Product
    EvtSpinAmp operator*(const EvtSpinAmp&)const;
    EvtSpinAmp& operator*=( const EvtSpinAmp& );

    EvtSpinAmp& operator*=( const EvtComplex& );
    EvtSpinAmp& operator/=( const EvtComplex& );

    // Contraction of amplitudes
    void intcont( size_t, size_t );
    void extcont( const EvtSpinAmp&, int, int );

    // assign this value to every member in the container
    void assign( const EvtComplex& val ) { _elem.assign( _elem.size(), val ); }

    // get the order of the container
    size_t rank() const { return _twospin.size(); }

    // get the dimension vector of the container
    const vector<unsigned int>& dims() const { return _twospin; }

    // set the elements and the dimensions of the vector - useful for something
    // things eventough it is usually not the cleanest solution
    void addspin( int twospin ) { _twospin.push_back( twospin ); }
    void setelem( const vector<EvtComplex>& elem ) { _elem = elem; }

    bool iterate( vector<int>& index ) const;
    vector<int> iterinit() const;

    bool allowed( const vector<int>& index ) const;
    bool iterateallowed( vector<int>& index ) const;
    vector<int> iterallowedinit() const;

  private:
    void checkindexargs( const vector<int>& index ) const;
    void checktwospin( const vector<unsigned int>& twospin ) const;
    int findtrueindex( const vector<int>& index ) const;
    vector<unsigned int> calctwospin(
        const vector<EvtSpinType::spintype>& type ) const;

    vector<EvtSpinType::spintype> _type;
    vector<unsigned int> _twospin;
    vector<EvtComplex> _elem;
};

#endif    // __EVTSPINAMP__