otbCzihoSOMLearningBehaviorFunctor.h

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/*
 * Copyright (C) 2005-2022 Centre National d'Etudes Spatiales (CNES)
 * Copyright (C) 2007-2012 Institut Mines Telecom / Telecom Bretagne
 *
 * 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 otbCzihoSOMLearningBehaviorFunctor_h
#define otbCzihoSOMLearningBehaviorFunctor_h
 
#include "itkSize.h"
#include "otbMath.h"
 
namespace otb
{
 
namespace Functor
{
 
class CzihoSOMLearningBehaviorFunctor
{
public:
  CzihoSOMLearningBehaviorFunctor()
  {
    m_IterationThreshold = 0;
  }
  virtual ~CzihoSOMLearningBehaviorFunctor()
  {
  }
 
  unsigned int GetIterationThreshold()
  {
    return this->m_IterationThreshold;
  }
 
  template <unsigned int VDimension>
  void SetIterationThreshold(const itk::Size<VDimension>& sizeInit, unsigned int iterMax)
  {
    double V0 = static_cast<double>(sizeInit[0]);
    for (unsigned int i = 1; i < VDimension; ++i)
    {
      if (V0 < static_cast<double>(sizeInit[i]))
        V0 = static_cast<double>(sizeInit[i]);
    }
 
    m_IterationThreshold = static_cast<unsigned int>(static_cast<double>(iterMax) * (1.0 - 1.0 / ::std::sqrt(V0)));
  }
 
  virtual double operator()(unsigned int currentIteration, unsigned int numberOfIterations, double betaInit, double betaEnd) const
  {
    if (currentIteration < m_IterationThreshold)
    {
      return betaInit * (1.0 - static_cast<double>(currentIteration) / static_cast<double>(numberOfIterations));
    }
    else
    {
      return betaEnd * (1.0 - static_cast<double>(currentIteration - m_IterationThreshold) / static_cast<double>(numberOfIterations - m_IterationThreshold));
    }
  }
 
private:
  unsigned int m_IterationThreshold;
 
}; // end of class CzihoSOMLearningBehaviorFunctor
 
} // end namespace Functor
 
} // end namespace otb
 
#endif