Reduce Peak Memory Consumption about connected-components-3d

[william-silversmith]

With regards to allowing binary images represented as std::vector<bool>, this is simple to do through the C++ interface, but may require copy-pasting a lot of code (ugly). It's not so simple to do through the Cython interface. If there's demand for this, let me know, but it should be pretty easy to just change some declarations to const std::vector<bool> &in_labels in a few places if that's what you need.

[william-silversmith]

https://pypi.org/project/bitarray/

[william-silversmith]

Previously, playing around with bit packing was sure to reduce performance and not really significantly reduce memory because of the output image and union find. However, after zeroth pass was implemented bit packing can save 20% (uint32) to 40% (for uint16) on peak memory. Might be worth looking into.

[william-silversmith]

Looks like std::bitset and std::vector would be annoying to work with in different respects. Will have to write own bit accessor class that accepts a byte string with zero parsing.

[william-silversmith]

Might be able to do something with np.packbits