message: Reintroduced epsilon in ConjugateGradientImageFilter to avoid division by zero
diff: #ifndef rtkConjugateGradientImageFilter_hxx
  #define rtkConjugateGradientImageFilter_hxx
  -#include <itkImageFileWriter.h>
  #include "rtkConjugateGradientImageFilter.h"
  #if ITK_VERSION_MAJOR>=5
  #include <itkMultiThreaderBase.h>
  @@ -154,7 +153,8 @@ void ConjugateGradientImageFilter<OutputImageType>
  m_A->Update();
  // Declare intermediate variables
  - DataType numerator, denominator, alpha, beta;
  + DataType numerator, denominator, alpha, beta, eps;
  + eps = itk::NumericTraits<DataType>::min(eps);
  #if ITK_VERSION_MAJOR<5
  // Declare iterators that will be used throughout the calculations
  @@ -262,7 +262,7 @@ void ConjugateGradientImageFilter<OutputImageType>
  nullptr
  );
  #endif
  - alpha = numerator / denominator;
  + alpha = numerator / (denominator + eps);
  #if ITK_VERSION_MAJOR<5
  itP = itk::ImageRegionIterator<OutputImageType>(Pk, largest);
  @@ -329,7 +329,7 @@ void ConjugateGradientImageFilter<OutputImageType>
  nullptr
  );
  #endif
  - beta = numerator / denominator;
  + beta = numerator / (denominator + eps);
  #if ITK_VERSION_MAJOR<5
  // Compute Pk+1
  @@ -364,7 +364,6 @@ void ConjugateGradientImageFilter<OutputImageType>
  // recompute its output at the beginning of next iteration
  Pk->Modified();
  }
  -
  m_A->GetOutput()->ReleaseData();
  }
  }// end namespace
  