Use an iterator 'WithIndex' when the index is retrieved during each iteration#5814
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thewtex merged 2 commits intoInsightSoftwareConsortium:mainfrom Feb 20, 2026
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These could be squashed into one or two commits (the one with future legacy deprecation could be separate commit). Good even as-is.
Replaced iterators "without index" with the corresponding iterators "with index", and replaced `ComputeIndex()` calls with `GetIndex()`. In these cases, an iterator _with index_ is much faster than an iterator that _computes_ the index, because in these cases the index is retrieved during _each_ iteration of the loop. Aims to speed up of the following filters: - AccumulateImageFilter - BinomialBlurImageFilter - DifferenceOfGaussiansGradientImageFilter - HardConnectedComponentImageFilter - InvertDisplacementFieldImageFilter - IterativeInverseDisplacementFieldImageFilter - LabelGeometryImageFilter - MirrorPadImageFilter - SpatialFunctionImageEvaluatorFilter As well as: - GaussianImageSource - ScalarChanAndVeseLevelSetFunction
Deprecated ("future removed") the nested type alias `OutputIterator` from
IterativeInverseDisplacementFieldImageFilter, as it is no longer used by now.
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thewtex
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When the index is retrieved during each iteration, an iterator with index (like
ImageRegionIteratorWithIndex) is much faster than an iterator that computes the index (likeImageRegionIterator).This pull request proposes to use an iterator with index, instead of an iterator that computes the index, in such cases.
It aims to speed up the following filters:
As well as:
This pull request also proposes to deprecate
IterativeInverseDisplacementFieldImageFilter::OutputIterator, as it is no longer used by now.