itkGradientDescentOptimizerBasev4.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 itkGradientDescentOptimizerBasev4_h
#define itkGradientDescentOptimizerBasev4_h

#include "itkObjectToObjectOptimizerBase.h"
#include "itkWindowConvergenceMonitoringFunction.h"
#include "itkThreadedIndexedContainerPartitioner.h"
#include "itkDomainThreader.h"

namespace itk
{
template<typename TInternalComputationValueType>
class ITK_TEMPLATE_EXPORT GradientDescentOptimizerBasev4Template
  : public ObjectToObjectOptimizerBaseTemplate<TInternalComputationValueType>
{
public:
  ITK_DISALLOW_COPY_AND_ASSIGN(GradientDescentOptimizerBasev4Template);

  using Self = GradientDescentOptimizerBasev4Template;
  using Superclass = ObjectToObjectOptimizerBaseTemplate<TInternalComputationValueType>;
  using Pointer = SmartPointer< Self >;
  using ConstPointer = SmartPointer< const Self >;

  itkTypeMacro(GradientDescentOptimizerBasev4Template, Superclass);

  typedef enum {
    MAXIMUM_NUMBER_OF_ITERATIONS,
    COSTFUNCTION_ERROR,
    UPDATE_PARAMETERS_ERROR,
    STEP_TOO_SMALL,
    CONVERGENCE_CHECKER_PASSED,
    GRADIENT_MAGNITUDE_TOLEARANCE,
    OTHER_ERROR
    } StopConditionType;

  using StopConditionReturnStringType = typename Superclass::StopConditionReturnStringType;

  using StopConditionDescriptionType = typename Superclass::StopConditionDescriptionType;

  using InternalComputationValueType = TInternalComputationValueType;

  using MetricType = typename Superclass::MetricType;
  using MetricTypePointer = typename MetricType::Pointer;

  using DerivativeType = typename Superclass::DerivativeType;

  using MeasureType = typename Superclass::MeasureType;

  using ScalesType = typename Superclass::ScalesType;

  using ParametersType = typename Superclass::ParametersType;

  using ConvergenceMonitoringType = itk::Function::WindowConvergenceMonitoringFunction<TInternalComputationValueType>;

  itkGetConstReferenceMacro( Gradient, DerivativeType );

  itkGetConstReferenceMacro(StopCondition, StopConditionType);

  void SetNumberOfIterations( const SizeValueType numberOfIterations ) override
    {
    itkDebugMacro("setting NumberOfIterations to " << numberOfIterations );
    if ( this->m_NumberOfIterations != numberOfIterations)
      {
      this->m_NumberOfIterations = numberOfIterations;
      this->Modified();
      }
    }

  SizeValueType GetNumberOfIterations() const override
    {
    return this->m_NumberOfIterations;
    }

  SizeValueType GetCurrentIteration() const override
    {
    return this->m_CurrentIteration;
    }

  void StartOptimization( bool doOnlyInitialization = false ) override;

  virtual void ResumeOptimization() = 0;

  virtual void StopOptimization();

  const StopConditionReturnStringType GetStopConditionDescription() const override;

  virtual void ModifyGradientByScales();
  virtual void ModifyGradientByLearningRate();

  using IndexRangeType = ThreadedIndexedContainerPartitioner::IndexRangeType;

  virtual void ModifyGradientByScalesOverSubRange( const IndexRangeType& subrange ) = 0;

  virtual void ModifyGradientByLearningRateOverSubRange( const IndexRangeType& subrange ) = 0;

protected:

  GradientDescentOptimizerBasev4Template();
  ~GradientDescentOptimizerBasev4Template() override = default;

  bool m_DoEstimateLearningRateAtEachIteration;

  bool m_DoEstimateLearningRateOnce;

  TInternalComputationValueType  m_MaximumStepSizeInPhysicalUnits;

  bool m_UseConvergenceMonitoring;

  SizeValueType m_ConvergenceWindowSize;

  typename ConvergenceMonitoringType::Pointer m_ConvergenceMonitoring;

  typename DomainThreader<ThreadedIndexedContainerPartitioner, Self>::Pointer m_ModifyGradientByScalesThreader;
  typename DomainThreader<ThreadedIndexedContainerPartitioner, Self>::Pointer m_ModifyGradientByLearningRateThreader;

  /* Common variables for optimization control and reporting */
  bool                          m_Stop{false};
  StopConditionType             m_StopCondition;
  StopConditionDescriptionType  m_StopConditionDescription;

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

private:

};

using GradientDescentOptimizerBasev4 = GradientDescentOptimizerBasev4Template<double>;

} // end namespace itk

#ifndef ITK_MANUAL_INSTANTIATION
#include "itkGradientDescentOptimizerBasev4.hxx"
#endif

#endif