itkRegularStepGradientDescentOptimizerv4.h

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/*=========================================================================
 *
 *  Copyright Insight Software Consortium
 *
 *  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.txt
 *
 *  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 itkRegularStepGradientDescentOptimizerv4_h
#define itkRegularStepGradientDescentOptimizerv4_h

#include "itkGradientDescentOptimizerv4.h"
#include <itkCompensatedSummation.h>

namespace itk
{
template<typename TInternalComputationValueType>
class ITK_TEMPLATE_EXPORT RegularStepGradientDescentOptimizerv4
: public GradientDescentOptimizerv4Template<TInternalComputationValueType>
{
public:
  ITK_DISALLOW_COPY_AND_ASSIGN(RegularStepGradientDescentOptimizerv4);

  using Self = RegularStepGradientDescentOptimizerv4;
  using Superclass = GradientDescentOptimizerv4Template<TInternalComputationValueType>;
  using Pointer = SmartPointer< Self >;
  using ConstPointer = SmartPointer< const Self >;

  itkTypeMacro(RegularStepGradientDescentOptimizerv4, GradientDescentOptimizerv4Template);

  itkNewMacro(Self);


  using InternalComputationValueType = TInternalComputationValueType;

  using DerivativeType = typename Superclass::DerivativeType;

  using MeasureType = typename Superclass::MeasureType;
  using IndexRangeType = typename Superclass::IndexRangeType;
  using ScalesType = typename Superclass::ScalesType;
  using ParametersType = typename Superclass::ParametersType;
  using StopConditionType = typename Superclass::StopConditionType;

  using CompensatedSummationType = CompensatedSummation< InternalComputationValueType >;

  itkSetMacro(MinimumStepLength, TInternalComputationValueType);
  itkGetConstReferenceMacro(MinimumStepLength, TInternalComputationValueType);

  itkSetMacro(RelaxationFactor, TInternalComputationValueType);
  itkGetConstReferenceMacro(RelaxationFactor, TInternalComputationValueType);

  itkSetMacro(GradientMagnitudeTolerance, TInternalComputationValueType);
  itkGetConstReferenceMacro(GradientMagnitudeTolerance, TInternalComputationValueType);

  itkSetMacro(CurrentLearningRateRelaxation, MeasureType);
  itkGetConstReferenceMacro(CurrentLearningRateRelaxation, MeasureType);

  void StartOptimization( bool doOnlyInitialization = false ) override;

  void EstimateLearningRate() override;

  double GetCurrentStepLength() const;

protected:

  void AdvanceOneStep() override;

  void ModifyGradientByScalesOverSubRange( const IndexRangeType& subrange ) override;
  void ModifyGradientByLearningRateOverSubRange( const IndexRangeType& subrange ) override;


  RegularStepGradientDescentOptimizerv4();

  ~RegularStepGradientDescentOptimizerv4() override = default;

  void PrintSelf( std::ostream & os, Indent indent ) const override;


private:
  TInternalComputationValueType  m_RelaxationFactor;

  TInternalComputationValueType  m_MinimumStepLength;

  TInternalComputationValueType  m_GradientMagnitudeTolerance;

  MeasureType                  m_CurrentLearningRateRelaxation;
};

} // end namespace itk

#ifndef ITK_MANUAL_INSTANTIATION
#include "itkRegularStepGradientDescentOptimizerv4.hxx"
#endif

#endif