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DIPlib / diplib

Quantitative Image Analysis in C++, MATLAB and Python
https://diplib.org
Apache License 2.0
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Optimize feature measurements #66

Closed milianw closed 3 years ago

milianw commented 3 years ago

Hey Cris!

This merge request fixes two performance issues that I stumbled over while profiling our QiTissue cell feature measurement code. Both patches are pretty small and simple, yet have quite a positive impact on our code base, so I hope we can merge this!

So far I only ran our own benchmarks, are there any within diplib itself that I should run and/or expand to get this in?

Cheers

crisluengo commented 3 years ago

Hi Millian!

Many thanks for this!

The only issue I see is that the operator+ for measurement data now will do the extra unnecessary ObjectExists(objectID) check for every object in the two data sets (by replacing out.AddObjectID_() with out.AddObjectID()). But that function is unnecessarily expensive anyway, I think it needs to be rewritten to use AddObjectIDs() instead.

milianw commented 3 years ago

Hey Cris,

many thanks for merging. I agree that operator+ is looking quite inefficient - porting it to AddObjectIDs would help a lot. It should also try to reserve the final (estimated) size in the object map and then bulk-merge those too. We aren't using that code path, so I was reluctant to do any invasive changes there...

crisluengo commented 3 years ago

Yes, indeed. I just pushed a commit improving operator+ in exactly the way you describe. :) 26c7a052bae4115a34a29d148159e45d98d40bba