text: /*=========================================================================
   *
   *  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 itkOptimizerParameterScalesEstimator_h
  #define itkOptimizerParameterScalesEstimator_h
  
  #include "itkObject.h"
  #include "itkObjectFactory.h"
  #include "itkOptimizerParameters.h"
  
  namespace itk
  {
  
  /** \class OptimizerParameterScalesEstimatorTemplate
   *  \brief OptimizerParameterScalesEstimatorTemplate is the base class offering a
   * empty method of estimating the parameter scales for optimizers.
   *
   * Its subclass RegistrationParameterScalesEstimator estimates scales for
   * registration optimizers.
   *
   * \ingroup ITKOptimizersv4
   */
  template <typename TInternalComputationValueType = double>
  class OptimizerParameterScalesEstimatorTemplate : public Object
  {
  public:
    ITK_DISALLOW_COPY_AND_ASSIGN(OptimizerParameterScalesEstimatorTemplate);
  
    /** Standard class type aliases. */
    using Self = OptimizerParameterScalesEstimatorTemplate;
    using Superclass = Object;
    using Pointer = SmartPointer<Self>;
    using ConstPointer = SmartPointer<const Self>;
  
    /** Run-time type information (and related methods). */
    itkTypeMacro(OptimizerParameterScalesEstimatorTemplate, Object);
  
    /** Type of scales */
    using ScalesType = OptimizerParameters<TInternalComputationValueType>;
    /** Type of parameters of the optimizer */
    using ParametersType = OptimizerParameters<TInternalComputationValueType>;
  
    /** Type of float */
    using FloatType = TInternalComputationValueType;
  
    /** Estimate parameter scales. */
    virtual void
    EstimateScales(ScalesType & scales) = 0;
  
    /** Estimate the scale of a step. */
    virtual FloatType
    EstimateStepScale(const ParametersType & step) = 0;
  
    /** Estimate the scales of local steps. */
    virtual void
    EstimateLocalStepScales(const ParametersType & step, ScalesType & localStepScales) = 0;
  
    /** Estimate the maximum size for steps. */
    virtual FloatType
    EstimateMaximumStepSize() = 0;
  
  protected:
    OptimizerParameterScalesEstimatorTemplate() = default;
    ~OptimizerParameterScalesEstimatorTemplate() override = default;
  
    void
    PrintSelf(std::ostream & os, Indent indent) const override
    {
      Superclass::PrintSelf(os, indent);
    }
  }; // class OptimizerParameterScalesEstimatorTemplate
  
  /** This helps to meet backward compatibility */
  using OptimizerParameterScalesEstimator = OptimizerParameterScalesEstimatorTemplate<double>;
  
  } // namespace itk
  
  #endif
  