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// Copyright (C) 2002 Ronan Collobert (collober@iro.umontreal.ca)
//
//
// This file is part of Torch. Release II.
// [The Ultimate Machine Learning Library]
//
// Torch 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.
//
// Torch 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 Torch; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#include "SVM.h"
namespace Torch {
SVM::SVM(Kernel *kernel_)
{
addROption("C", &C_cst, 100, "trade off margin/classification error");
kernel = kernel_;
data = kernel->data;
n_inputs = data->n_inputs;
n_outputs = 1;
support_vectors = NULL;
real_index = NULL;
n_support_vectors = 0;
addToList(&outputs, 1, xalloc(sizeof(real)));
}
void SVM::init()
{
QCMachine::init();
reset();
}
void SVM::forward(List *inputs)
{
real sum = 0;
for(int it = 0; it < n_support_vectors; it++)
{
int t = support_vectors[it];
sum += y[t]*alpha[t]*kernel->realEval(real_index[it], inputs);
}
sum += b;
((real *)outputs->ptr)[0] = sum;
}
bool SVM::bCompute()
{
real sum = 0;
int n_ = 0;
for(int it = 0; it < n_support_vectors; it++)
{
int t = support_vectors[it];
if( (alpha[t] > Cdown[t]+eps_bornes) && (alpha[t] < Cup[t]-eps_bornes) )
{
sum += y[t]*grad[t];
n_++;
}
}
if(n_)
{
b = -sum/(real)n_;
return(true);
}
else
return(false);
}
void SVM::loadFILE(FILE *file)
{
xfread(alpha, sizeof(real), l, file);
xfread(grad, sizeof(real), l, file);
xfread(y, sizeof(real), l, file);
checkSupportVectors();
}
void SVM::saveFILE(FILE *file)
{
xfwrite(alpha, sizeof(real), l, file);
xfwrite(grad, sizeof(real), l, file);
xfwrite(y, sizeof(real), l, file);
}
SVM::~SVM()
{
freeList(&outputs, true);
}
}
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