source: branches/0.4-stable/yat/classifier/PolynomialKernelFunction.cc @ 1392

// $Id$

/*
  Copyright (C) 2003 Peter Johansson
  Copyright (C) 2004, 2005, 2006, 2007 Jari Häkkinen, Peter Johansson
  Copyright (C) 2008 Peter Johansson

  This file is part of the yat library, http://dev.thep.lu.se/yat

  The yat library 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 2 of the
  License, or (at your option) any later version.

  The yat library 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 this program; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  02111-1307, USA.
*/

#include "PolynomialKernelFunction.h"
#include "DataLookup1D.h"
#include "DataLookupWeighted1D.h"
#include "yat/statistics/AveragerPairWeighted.h"

#include <cassert>
#include <cmath>

namespace theplu {
namespace yat {
namespace classifier {  

PolynomialKernelFunction::PolynomialKernelFunction(int order) 
  : KernelFunction(), order_(order)
{
}


double PolynomialKernelFunction::operator()(const DataLookup1D& x,
                                            const DataLookup1D& y) const   
{ 
  assert(x.size()==y.size());
  return ((order_>1) ? pow(1+x*y,order_) : x*y); 
}


double PolynomialKernelFunction::operator()(const DataLookup1D& x,
                                            const DataLookupWeighted1D& y) const
{ 
  assert(x.size()==y.size());
  statistics::AveragerPairWeighted averager;
  add(averager, x.begin(),x.end(), y.begin());
  if(order_>1) 
    return pow(1+averager.sum_xy(),order_);
  return averager.sum_xy();
}


double PolynomialKernelFunction::operator()(const DataLookupWeighted1D& x,
                                            const DataLookupWeighted1D& y) const
{ 
  assert(x.size()==y.size());
  statistics::AveragerPairWeighted averager;
  add(averager, x.begin(), x.end(),y.begin());
  if(order_>1) 
    return pow(1+averager.sum_xy(),order_);
  return averager.sum_xy();
}


}}} // of namespace cpptools, yat, and theplu