Online quantization algorithm for gudhi

[tlacombe]

Provide a quantization algorithm to "summarize" a collection of persistence diagrams.

(At least) One thing that may be discussed :

• I put the code in the python/gudhi/wasserstein/ repo, because it is of a "Wasserstein metric" flavor (we minimize something in terms of Wasserstein distance between persistence diagrams). However, it does not rely on POT as other functions in this repo do ; we actually never need to explicitly compute a Wasserstein distance/matching explicitly. Perhaps would it belong directly to the gudhi/ repo ?

Also TODO :

• [x] Check for quantization.py : is the copyright correct?

[VincentRouvreau]

IMHO the copyright is correct.

[tlacombe]

IMHO the copyright is correct.

Great ! Though, shouldn't it be 2021, now that I read it?

[VincentRouvreau]

IMHO the copyright is correct.

Great ! Though, shouldn't it be 2021, now that I read it?

Yes !

[tlacombe]

Corrected. Any thought on if this code belong to the /wasserstein module? From a theoretical perspective, the goal is to solve some minimization with respect to the Wasserstein distance between persistence diagrams (so it makes sense to put it there), but from a practical perspective (code), it does not rely on pot contrarily to other functions in the /wasserstein module (because we can solve our optimization problem without explicitly computing such distances/matchings). My feeling is that it can stay there, doing gudhi.wasserstein.quantization makes clear that we are quantizing something with respect to the Wasserstein distance ; but I am open to discussion of course.

[tlacombe]

I just realized that I never managed to do the last requested modifications (my local build was broken for some reason at that time). I finally did it. As I'm working on a new machine, I hope I managed correctly the fork/branching/etc.

PS : and one day later I realize that I forgot to post this comment... :sleeping: