LaplacianKernel.cc

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// -*- C++ -*-

// PLearn (A C++ Machine Learning Library)
// Copyright (C) 1998 Pascal Vincent
// Copyright (C) 1999-2002 Pascal Vincent, Yoshua Bengio, Rejean Ducharme and University of Montreal
// Copyright (C) 2001-2002 Nicolas Chapados, Ichiro Takeuchi, Jean-Sebastien Senecal
// Copyright (C) 2002 Xiangdong Wang, Christian Dorion

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/* *******************************************************      
   * $Id: LaplacianKernel.cc,v 1.4 2004/04/07 23:15:17 morinf Exp $
   * This file is part of the PLearn library.
   ******************************************************* */

#include "LaplacianKernel.h"

namespace PLearn {
using namespace std;


PLEARN_IMPLEMENT_OBJECT(LaplacianKernel, "ONE LINE DESCR", "NO HELP");

real LaplacianKernel::evaluate(const Vec& x1, const Vec& x2) const
{ 
#ifdef BOUNDCHECK
  if(x1.length()!=x2.length())
    PLERROR("IN LaplacianKernel::evaluate x1 and x2 must have the same length");
#endif

  real summ = 0.0;
  real* v1=x1.data();
  real* v2=x2.data();
  int n=x1.length();
  for(int i=0; i<n; i++)
    summ += fabs(v1[i]-v2[i]);
  return exp(-phi*summ);
}

void LaplacianKernel::declareOptions(OptionList &ol)
{
    declareOption(ol, "phi", &LaplacianKernel::phi, OptionBase::buildoption,
                  "TODO: Some comments");
    inherited::declareOptions(ol);
}

} // end of namespace PLearn

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