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PERF: Use Boost.SmallVec in BCO interpolator

Laurențiu Nicola requested to merge bco-small-vec into develop


Use a small vector container for the output pixel and interpolator coefficients in BCOInterpolateImageFunction.


This avoids two (for scalar images) or three (for vector ones) for small interpolation radii and number of bands.

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Tested on Ubuntu 18.04. I expect it might make a larger difference on older systems, because the GLIBC memory allocator used to be very slow (it got a per-thread cache in 2.26).

Implementation Details

I'm not sure what's the minimum Boost version we support, so I left in a path for pre-1.58, where small_vector is not available.

Additional notes

This is technically a breaking change:

  • the BCOInterpolateImageFunctionBase::CoefContainer type is public and its type has changed
  • BCOInterpolateImageFunctionBase::EvaluateCoef is no longer virtual


The copyright owner is Laurențiu Nicola / CS ROMANIA and has signed the ORFEO ToolBox Contributor License Agreement.

Check before merging:

  • All discussions are resolved
  • At least 2 👍 votes from core developers, no 👎 vote.
  • The feature branch is (reasonably) up-to-date with the base branch
  • Dashboard is green
  • Copyright owner has signed the ORFEO ToolBox Contributor License Agreement
  • Optionally, run git diff develop... -U0 --no-color | -p1 -i on latest changes and commit
Edited by Laurențiu Nicola

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