itkFiniteDifferenceGradientDescentOptimizer.h

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/*=========================================================================
 *
 *  Copyright UMC Utrecht and contributors
 *
 *  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.
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 *=========================================================================*/
 
#ifndef itkFiniteDifferenceGradientDescentOptimizer_h
#define itkFiniteDifferenceGradientDescentOptimizer_h
 
#include "itkScaledSingleValuedNonLinearOptimizer.h"
 
namespace itk
{
 
class FiniteDifferenceGradientDescentOptimizer : public ScaledSingleValuedNonLinearOptimizer
{
public:
  ITK_DISALLOW_COPY_AND_MOVE(FiniteDifferenceGradientDescentOptimizer);
 
  using Self = FiniteDifferenceGradientDescentOptimizer;
  using Superclass = ScaledSingleValuedNonLinearOptimizer;
  using Pointer = SmartPointer<Self>;
  using ConstPointer = SmartPointer<const Self>;
 
  itkNewMacro(Self);
 
  itkTypeMacro(FiniteDifferenceGradientDescentOptimizer, ScaledSingleValuedNonLinearOptimizer);
 
  enum StopConditionType
  {
    MaximumNumberOfIterations,
    MetricError
  };
 
  virtual void
  AdvanceOneStep();
 
  void
  StartOptimization() override;
 
  void
  ResumeOptimization();
 
  void
  StopOptimization();
 
  itkSetMacro(NumberOfIterations, unsigned long);
 
  itkGetConstMacro(NumberOfIterations, unsigned long);
 
  itkGetConstMacro(CurrentIteration, unsigned long);
 
  itkGetConstMacro(Value, double);
 
  itkGetConstMacro(StopCondition, StopConditionType);
 
  itkSetMacro(Param_a, double);
  itkGetConstMacro(Param_a, double);
 
  itkSetMacro(Param_c, double);
  itkGetConstMacro(Param_c, double);
 
  itkSetMacro(Param_A, double);
  itkGetConstMacro(Param_A, double);
 
  itkSetMacro(Param_alpha, double);
  itkGetConstMacro(Param_alpha, double);
 
  itkSetMacro(Param_gamma, double);
  itkGetConstMacro(Param_gamma, double);
 
  itkGetConstMacro(ComputeCurrentValue, bool);
  itkSetMacro(ComputeCurrentValue, bool);
  itkBooleanMacro(ComputeCurrentValue);
 
  itkGetConstMacro(GradientMagnitude, double);
  itkGetConstMacro(LearningRate, double);
 
protected:
  FiniteDifferenceGradientDescentOptimizer();
  ~FiniteDifferenceGradientDescentOptimizer() override = default;
 
  void
  PrintSelf(std::ostream & os, Indent indent) const override;
 
  // made protected so subclass can access
  DerivativeType m_Gradient;
  double         m_LearningRate{ 0.0 };
  double         m_GradientMagnitude{ 0.0 };
 
  bool m_ComputeCurrentValue{ false };
 
  // Functions to compute the parameters at iteration k.
  virtual double
  Compute_a(unsigned long k) const;
 
  virtual double
  Compute_c(unsigned long k) const;
 
private:
  bool              m_Stop{ false };
  double            m_Value{ 0.0 };
  StopConditionType m_StopCondition{ MaximumNumberOfIterations };
  unsigned long     m_NumberOfIterations{ 100 };
  unsigned long     m_CurrentIteration{ 0 };
 
  double m_Param_a{ 1.0 };
  double m_Param_c{ 1.0 };
  double m_Param_A{ 1.0 };
  double m_Param_alpha{ 0.602 };
  double m_Param_gamma{ 0.101 };
};
 
} // end namespace itk
 
#endif // end #ifndef itkFiniteDifferenceGradientDescentOptimizer_h