[Insight-developers] Why is VariableLengthVector::GetSquaredNorm so slow?

[David Doria]

I have noticed that if I loop over the elements of two
VariableLengthVectors to compute the squared norm of their difference,
it is about 3x faster than if I use the GetSquaredNorm() function. I
have attached a demo which uses itkTimeProbe to show this. Can anyone
explain the difference? My ManualDifference2 seems to me to be
identical to GetSquaredNorm.

Thanks,

David
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