itkNormalVariateGenerator.h

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/*=========================================================================
 *
 *  Copyright NumFOCUS
 *
 *  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