itkNormalVariateGenerator.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 itkNormalVariateGenerator_h
#define itkNormalVariateGenerator_h

#include "itkObjectFactory.h"
#include "itkRandomVariateGeneratorBase.h"
#include "ITKStatisticsExport.h"

namespace itk
{
namespace Statistics
{
class ITKStatistics_EXPORT NormalVariateGenerator:
  public RandomVariateGeneratorBase
{
public:
  using Self = NormalVariateGenerator;
  using Superclass = RandomVariateGeneratorBase;
  using Pointer = SmartPointer< Self >;
  using ConstPointer = SmartPointer< const Self >;

  itkTypeMacro(NormalVariateGenerator,
               RandomVariateGeneratorBase);

  itkNewMacro(Self);

  void Initialize(int randomSeed);

  double GetVariate() override;

protected:
  NormalVariateGenerator();
  ~NormalVariateGenerator() override;
  void PrintSelf(std::ostream & os, Indent indent) const override;

  double FastNorm();

private:

  static inline int SignedShiftXOR( int irs )
    {
      // shifting of signed integer gives undefined results, explicitly
      // cast to unsigned to get expected ( if two complement
      // representation ) results.
      auto uirs = static_cast<unsigned int>(irs);
      return static_cast<int>(( irs <= 0 ) ? ( (  uirs << 1 ) ^ 333556017 ) : ( uirs << 1 ));
    }

  double m_Scale;
  double m_Rscale;
  double m_Rcons;
  int    m_ELEN;
  int    m_LEN;
  int    m_LMASK;
  int    m_TLEN;

  int  m_Gaussfaze;
  int *m_Gausssave;

  double m_GScale;

  int *  m_Vec1;
  int    m_Nslew;
  int    m_Irs;
  int    m_Lseed;
  double m_Chic1;
  double m_Chic2;
  double m_ActualRSD;
};  // end of class
} // end of namespace Statistics
} // end of namespace itk
#endif