itkImageRandomNonRepeatingConstIteratorWithIndex.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 itkImageRandomNonRepeatingConstIteratorWithIndex_h
#define itkImageRandomNonRepeatingConstIteratorWithIndex_h

#include "itkImageConstIteratorWithIndex.h"
#include <algorithm>
#include <iostream>
#include "itkMersenneTwisterRandomVariateGenerator.h"

namespace itk
{
class NodeOfPermutation
{
public:
  SizeValueType m_Priority;
  SizeValueType m_Index;
  double        m_Value;

  NodeOfPermutation ()
  {
    m_Priority = 0;
    m_Index = 0;
    m_Value = 0.0;
  }

  bool operator<(const NodeOfPermutation & b) const
  {
    if ( m_Priority == b.m_Priority )
      {
      return m_Value < b.m_Value;
      }
    else
      {
      return m_Priority < b.m_Priority;
      }
  }
};

class RandomPermutation
{
public:
  using GeneratorPointer = typename Statistics::MersenneTwisterRandomVariateGenerator::Pointer;
  NodeOfPermutation *m_Permutation;
  GeneratorPointer   m_Generator;
  SizeValueType      m_Size;

  RandomPermutation(SizeValueType sz)
  {
    m_Size = sz;
    m_Permutation = new NodeOfPermutation[m_Size];
    m_Generator = Statistics::MersenneTwisterRandomVariateGenerator::New();
    this->Shuffle();
  }

  RandomPermutation &operator=(const RandomPermutation &it)
    {
      delete[] m_Permutation;
      m_Size = it.m_Size;
      m_Permutation = new NodeOfPermutation[m_Size];
      m_Generator = it.m_Generator;
      return *this;
    }

  void SetPriority(SizeValueType i, SizeValueType priority)
  {
    if ( i > m_Size )
      {
      std::ostringstream ostrm;
      ostrm << "Error: RandomPermuation does not have " << i << " elements" << std::endl;
      throw std::runtime_error(ostrm.str());
      }
    else
      {
      m_Permutation[i].m_Priority = priority;
      }
  }

  void Shuffle()
  {
    for ( SizeValueType i = 0; i < m_Size; i++ )
      {
      m_Permutation[i].m_Value = m_Generator->GetVariateWithClosedRange (1.0);
      m_Permutation[i].m_Index = i;
      }
    std::sort(m_Permutation, m_Permutation + m_Size);
  }

  SizeValueType operator[](SizeValueType i)
  {
    return m_Permutation[i].m_Index;
  }

  ~RandomPermutation()
  {
    delete[] m_Permutation;
  }

  void ReinitializeSeed()
  {
    m_Generator->Initialize();
  }

  void ReinitializeSeed(unsigned int seed)
  {
    m_Generator->SetSeed (seed);
  }
};

template< typename TImage >
class ITK_TEMPLATE_EXPORT ImageRandomNonRepeatingConstIteratorWithIndex:public ImageConstIteratorWithIndex< TImage >
{
public:
  using Self = ImageRandomNonRepeatingConstIteratorWithIndex;
  using Superclass = ImageConstIteratorWithIndex< TImage >;

  using IndexType = typename Superclass::IndexType;
  using SizeType = typename Superclass::SizeType;
  using OffsetType = typename Superclass::OffsetType;
  using RegionType = typename Superclass::RegionType;
  using ImageType = typename Superclass::ImageType;
  using PixelContainer = typename Superclass::PixelContainer;
  using PixelContainerPointer = typename Superclass::PixelContainerPointer;
  using InternalPixelType = typename Superclass::InternalPixelType;
  using PixelType = typename Superclass::PixelType;
  using AccessorType = typename Superclass::AccessorType;
  using IndexValueType = typename Superclass::IndexValueType;
  using OffsetValueType = typename Superclass::OffsetValueType;
  using SizeValueType = typename Superclass::SizeValueType;

  ImageRandomNonRepeatingConstIteratorWithIndex();
  ~ImageRandomNonRepeatingConstIteratorWithIndex() override
  {
    delete m_Permutation;
  }

  ImageRandomNonRepeatingConstIteratorWithIndex(const ImageType *ptr, const RegionType & region);

  ImageRandomNonRepeatingConstIteratorWithIndex(const ImageConstIteratorWithIndex< TImage > & it)
  {
    this->ImageConstIteratorWithIndex< TImage >::operator=(it);

    m_Permutation = nullptr;
  }

  Self & operator=(const Self & it);

  void GoToBegin()
  {
    m_NumberOfSamplesDone = 0L;
    this->UpdatePosition();
  }

  void GoToEnd()
  {
    m_NumberOfSamplesDone = m_NumberOfSamplesRequested;
    this->UpdatePosition();
  }

  bool IsAtBegin() const
  {
    return ( m_NumberOfSamplesDone == 0L );
  }

  bool IsAtEnd() const
  {
    return ( m_NumberOfSamplesDone >= m_NumberOfSamplesRequested );
  }

  static constexpr unsigned int ImageDimension = TImage::ImageDimension;

  using PriorityImageType = itk::Image< SizeValueType, Self::ImageDimension >;

  void SetPriorityImage(const PriorityImageType *priorityImage);

  Self & operator++()
  {
    m_NumberOfSamplesDone++;
    this->UpdatePosition();
    return *this;
  }

  Self & operator--()
  {
    m_NumberOfSamplesDone--;
    this->UpdatePosition();
    return *this;
  }

  void SetNumberOfSamples(SizeValueType number);

  SizeValueType GetNumberOfSamples() const;

  void ReinitializeSeed();

  void ReinitializeSeed(int);

private:
  void UpdatePosition();

  SizeValueType      m_NumberOfSamplesRequested;
  SizeValueType      m_NumberOfSamplesDone;
  SizeValueType      m_NumberOfPixelsInRegion;
  RandomPermutation *m_Permutation;
};
} // end namespace itk

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

#endif