EvtAmpIndex.cc

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//--------------------------------------------------------------------------
//
// Environment:
//      This software is part of the EvtGen package developed jointly
//      for the BaBar and CLEO collaborations.  If you use all or part
//      of it, please give an appropriate acknowledgement.
//
// Copyright Information: See EvtGen/COPYRIGHT
//      Copyright (C) 2002      Caltech
//
// Module: EvtAmp.cc
//
// Description: Class to manipulate the amplitudes in the decays.
//
// Modification history:
//
//    RYD     Nov 22, 2002         Module created
//
//------------------------------------------------------------------------
// 
#include "EvtGenBase/EvtPatches.hh"
#include "EvtGenBase/EvtAmpIndex.hh"
#include <vector>
using std::vector;
 
 
EvtAmpIndex::EvtAmpIndex(std::vector<int> ind):
  _ind(ind),
  _size(ind.size()),
  _state(ind.size()),
  _nstate(ind.size())
{
  int i;
  
  for(i=0;i<_size;i++) {
    _state[i]=0;
    if (i==0){
      _nstate[i]=1;
    }
    else{
      _nstate[i]=_nstate[i-1]*_ind[i];
    }
  }
}
 
 
void EvtAmpIndex::reset(){
  int i;
  for(i=0;i<_size;i++) {
    _state[i]=0;
  }
}
 
bool EvtAmpIndex::next(){
  int i;
  for(i=0;i<_size;i++) {
    _state[i]++;
    if (_state[i]<_ind[i]){
      return true;
    }
    else{
      _state[i]=0;
    }
  }
  return false;
}
 
int EvtAmpIndex::index(){
 
  int i;
  int ind=0;
 
  for(i=0;i<_size;i++) {
    ind+=_state[i]*_nstate[i];
  }
 
  return ind;
 
}