itkMembershipFunctionBase.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 itkMembershipFunctionBase_h
#define itkMembershipFunctionBase_h

#include "itkFunctionBase.h"
#include "itkMeasurementVectorTraits.h"
#include "itkNumericTraitsCovariantVectorPixel.h"

namespace itk
{
namespace Statistics
{
template< typename TVector >
class ITK_TEMPLATE_EXPORT MembershipFunctionBase:
  public FunctionBase< TVector, double >
{
public:
  ITK_DISALLOW_COPY_AND_ASSIGN(MembershipFunctionBase);

  using Self = MembershipFunctionBase;
  using Superclass = FunctionBase< TVector, double >;
  using Pointer = SmartPointer< Self >;
  using ConstPointer = SmartPointer< const Self >;

  itkTypeMacro(MembershipFunctionBase, FunctionBase);

  using MeasurementVectorType = TVector;

  using MeasurementVectorSizeType = unsigned int;

  double Evaluate(const MeasurementVectorType & x) const override = 0;

  virtual void SetMeasurementVectorSize(MeasurementVectorSizeType s)
  {
    // Test whether the vector type is resizable or not
    MeasurementVectorType m;

    if ( MeasurementVectorTraits::IsResizable(m) )
      {
      // then this is a resizable vector type
      //
      // if the new size is the same as the previou size, just return
      if ( s == this->m_MeasurementVectorSize )
        {
        return;
        }
      else
        {
        this->m_MeasurementVectorSize = s;
        this->Modified();
        }
      }
    else
      {
      // If this is a non-resizable vector type
      MeasurementVectorType     m3;
      MeasurementVectorSizeType defaultLength =
        NumericTraits<MeasurementVectorType>::GetLength(m3);
      // and the new length is different from the default one, then throw an
      // exception
      if ( defaultLength != s )
        {
        itkExceptionMacro(
          "Attempting to change the measurement vector size of a non-resizable vector type" );
        }
      }
  }

  itkGetConstMacro(MeasurementVectorSize, MeasurementVectorSizeType);

protected:
  MembershipFunctionBase()
  {
    m_MeasurementVectorSize = NumericTraits<MeasurementVectorType>::GetLength(
      MeasurementVectorType() );
  }

  ~MembershipFunctionBase() override = default;

  void PrintSelf(std::ostream & os, Indent indent) const override
  {
    Superclass::PrintSelf(os, indent);
    os << indent << "Length of measurement vectors: "
       << m_MeasurementVectorSize << std::endl;
  }

private:
  MeasurementVectorSizeType m_MeasurementVectorSize;

};  // end of class
} // end of namespace Statistics
} // end namespace itk

#endif