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/*
* Copyright (C) 2005-2020 Centre National d'Etudes Spatiales (CNES)
*
* This file is part of Orfeo Toolbox
*
* https://www.orfeo-toolbox.org/
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef otbSVMCrossValidationCostFunction_hxx
#define otbSVMCrossValidationCostFunction_hxx
#include "otbSVMCrossValidationCostFunction.h"
#include "otbMacro.h"
namespace otb
{
template <class TModel>
SVMCrossValidationCostFunction<TModel>::SVMCrossValidationCostFunction() : m_Model(), m_DerivativeStep(0.001)
{
}
template <class TModel>
SVMCrossValidationCostFunction<TModel>::~SVMCrossValidationCostFunction()
{
}
template <class TModel>
typename SVMCrossValidationCostFunction<TModel>::MeasureType SVMCrossValidationCostFunction<TModel>::GetValue(const ParametersType& parameters) const
{
// Check the input model
if (!m_Model)
{
itkExceptionMacro(<< "Model is null, can not evaluate accuracy.");
}
// Check for a positive and non-null C
if (parameters[0] <= 0)
{
return 0;
}
// Updates vm_parameters according to current parameters
this->UpdateParameters(parameters);
return m_Model->CrossValidation();
}
template <class TModel>
void SVMCrossValidationCostFunction<TModel>::GetDerivative(const ParametersType& parameters, DerivativeType& derivative) const
{
// Set derivative size
derivative.SetSize(parameters.Size());
derivative.Fill(itk::NumericTraits<ParametersValueType>::Zero);
for (unsigned int i = 0; i < parameters.Size(); ++i)
{
MeasureType y1, y2;
ParametersType x1, x2;
x1 = parameters;
x1[i] -= m_DerivativeStep;
y1 = this->GetValue(x1);
x2 = parameters;
x2[i] += m_DerivativeStep;
y2 = this->GetValue(x2);
derivative[i] = (y2 - y1) / (2 * m_DerivativeStep);
otbMsgDevMacro(<< "x1= " << x1 << " x2= " << x2 << ", y1= " << y1 << ", y2= " << y2);
}
otbMsgDevMacro("Position: " << parameters << ", Value: " << this->GetValue(parameters) << ", Derivatives: " << derivative);
}
template <class TModel>
unsigned int SVMCrossValidationCostFunction<TModel>::GetNumberOfParameters(void) const
{
if (!m_Model)
{
itkExceptionMacro(<< "Model is null, can not evaluate number of parameters.");
}
return m_Model->GetNumberOfKernelParameters();
}
template <class TModel>
void SVMCrossValidationCostFunction<TModel>::UpdateParameters(const ParametersType& parameters) const
{
unsigned int nbParams = m_Model->GetNumberOfKernelParameters();
m_Model->SetC(parameters[0]);
if (nbParams > 1)
m_Model->SetKernelGamma(parameters[1]);
if (nbParams > 2)
m_Model->SetKernelCoef0(parameters[2]);
}
} // namespace otb
#endif
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