EvtOrthogVector.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) 2000 Caltech, LLNL
//
// Module: EvtGen/EvtOrthogVector.hh
//
// Description:
//
// Modification history:
//
// Lange August 11, 2000 Created
//
//------------------------------------------------------------------------
#include "EvtPatches.hh"
 
#include "EvtOrthogVector.hh"
#include <ctype.h>
#include <fstream>
#include <iostream>
#include <stdlib.h>
#include <string.h>
using std::fstream;
 
EvtOrthogVector::EvtOrthogVector( int n, std::vector<double>* vectors ) {
 
  _dimen = n;
  _holder.resize( n );
 
  std::vector<int> temp;
 
  int i;
  for ( i = 0; i < n; i++ )
  {
    _orthogVector.push_back( 0. );
    temp.push_back( i );
  }
 
  findOrthog( _dimen, temp, vectors );
}
 
EvtOrthogVector::~EvtOrthogVector() {}
 
void EvtOrthogVector::findOrthog( int dim, std::vector<int> invect,
                                  std::vector<double>* vectors ) {
 
  if ( dim == 2 )
  {
    _holder[0] = invect[0];
    _holder[1] = invect[1];
    int sign   = findEvenOddSwaps();
    {
      double addition = 1;
      int    i;
      for ( i = 1; i < _dimen; i++ ) { addition *= vectors[i - 1][_holder[i]]; }
      addition *= sign;
      _orthogVector[_holder[0]] += addition;
    }
 
    _holder[0] = invect[1];
    _holder[1] = invect[0];
 
    {
      double addition = 1;
      int    i;
      for ( i = 1; i < _dimen; i++ ) { addition *= vectors[i - 1][_holder[i]]; }
      addition *= sign;
      _orthogVector[_holder[0]] -= addition;
    }
 
    return;
  }
  else
  {
    std::vector<int> temp( ( 2 * dim ) );
 
    int i;
    for ( i = 0; i < dim; i++ ) temp[i] = invect[i];
    for ( i = 0; i < dim; i++ ) temp[i + dim] = invect[i];
 
    for ( i = 0; i < dim; i++ )
    {
      _holder[dim - 1] = temp[dim - 1 + i];
      std::vector<int> tempDim( ( dim - 1 ) );
 
      int j;
      for ( j = 0; j < ( dim - 1 ); j++ ) tempDim[j] = temp[j + i];
      findOrthog( dim - 1, tempDim, vectors );
    }
  }
 
  return;
}
 
int EvtOrthogVector::findEvenOddSwaps() {
 
  std::vector<int> temp( _dimen );
 
  int i, j, nSwap;
  for ( i = 0; i < _dimen; i++ ) temp[i] = _holder[i];
 
  nSwap = 0;
  for ( i = 0; i < ( _dimen - 1 ); i++ )
  {
    for ( j = i + 1; j < _dimen; j++ )
    {
 
      if ( temp[i] > temp[j] )
      {
        int duh = temp[j];
        temp[j] = temp[i];
        temp[i] = duh;
        nSwap += 1;
      }
    }
  }
  nSwap -= ( nSwap / 2 ) * 2;
 
  if ( nSwap ) return -1;
 
  return 1;
}