PERF: Use region iterator image ComposeBigVectorImageFilter #5306
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This test is timing out on nightly valgrind and coverage builds. These changes may reduce the number of temporaries heap allocations used, and improve performance. Local test in debug mode, improve performance by more than 10%.
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blowekamp
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N-Dekker
N-Dekker
reviewed
Apr 15, 2025
Comment on lines
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| itk::ImageRegionConstIterator<VectorImageType> it(img, sliceRegion); | ||
| for (it.GoToBegin(); !it.IsAtEnd(); ++it) |
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@blowekamp Cool. 👍 Some small suggestions...
it.GoToBegin() is not necessary. An ImageRegionConstIterator always starts at the begin. So these two lines could be replaced with one:
for (itk::ImageRegionConstIterator<VectorImageType> it(img, sliceRegion); !it.IsAtEnd(); ++it)
N-Dekker
reviewed
Apr 15, 2025
Comment on lines
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to
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| if (it.Get()[i] != i % 250) | ||
| { | ||
| itk::Index<3> idx = { { x, y, z } }; | ||
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| auto pixel = img->GetPixel(idx); | ||
| if (pixel[i] != i % 250) | ||
| { | ||
| ++values[pixel[i]]; | ||
| } | ||
| ++values[it.Get()[i]]; |
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If possible, I would avoid calling it.Get()[i] twice. Instead, would it also work as follows?
if (const auto channelValue = it.Get()[i]; channelValue != i % 250)
{
++values[channelValue];
}
N-Dekker
reviewed
Apr 15, 2025
| for (unsigned int i = 0; i < nchannels; ++i) | ||
| { | ||
| itk::IndexValueType z = i; | ||
| std::map<unsigned int, unsigned int> values; | ||
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| for (itk::IndexValueType y = 0; y < size; ++y) | ||
| sliceRegion.SetIndex(2, z); // Set the index of the z-dimension to the current slice |
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If z should always just have the same value as i (the current channel number), I would suggest removing the variable z, and using i directly:
sliceRegion.SetIndex(2, i);
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This test is timing out on nightly valgrind and coverage builds.
These changes may reduce the number of temporaries heap allocations used, and improve performance. Local test in debug mode, improve performance by more than 10%.
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