source: trunk/lib/classifier/PolynomialKernelFunction.cc @ 524

// $Id: PolynomialKernelFunction.cc 524 2006-02-23 15:55:33Z peter $


#include <c++_tools/classifier/PolynomialKernelFunction.h>

#include <c++_tools/gslapi/matrix.h>
#include <c++_tools/gslapi/vector.h>
#include <c++_tools/statistics/AveragerPairWeighted.h>

#include <cmath>


namespace theplu {
namespace classifier {  

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

double PolynomialKernelFunction::operator()(const gslapi::vector& a1,
                                            const gslapi::vector& a2,
                                            const gslapi::vector& w1,
                                            const gslapi::vector& w2) const   
{
  statistics::AveragerPairWeighted averager;
  averager.add(a1,a2,w1,w2);

  // a1.size() term to make it coherent with no weight case
  if(order_>1) 
    return pow(1+averager.sum_xy()/averager.sum_w()*a1.size(),order_);
  return averager.sum_xy()/averager.sum_w()*a1.size();
}

}} // of namespace cpptools and namespace theplu