[Refactoring] [Testing] [Feature] NoiseHandler

[chMoussa]

Supersedes #584 and solves #583 (besides plotting). We introduce a NoiseHandler class containing information about the noise. For digital noise, this means now that we can do a conversion in convert_ops to the right class in Pyq. @jpmoutinho also proposed to separate noise protocol types into Analog, Digital, and Readout (given that a same protocol name may be available in different settings such as depolarizing).

Note that a substantial harmonisation of naming may be needed between different backend (Readout is basically called SPAM in Pulser).

Todos:

• Redesign the previous Noise class into the NoiseHandler class to allow multiple combination of noise protocols.
• Change typings and replace DigitalNoise in blocks.
• Add conversion function for Pyq backend.
• Serialize noise in blocks
• Add Tests
• Elaborate the docs.

[chMoussa]

Thanks @chMoussa more comments from me as I think we can simplify further. Another point is about testing for composed noise models. Have you tried it out ?

Yes, I just added a parameterized test for this in qadence/tests/qadence/test_noise/test_digital_noise.py

[jpmoutinho]

Very nice @chMoussa, this looks much cleaner :)

I did not go into the full details of the code, let me know if there is something specific that you would like to discuss. But in general, this interface has my approval.

[RolandMacDoland]

Thanks @chMoussa. Sorry for being a pain but I think we still have too many types that makes the whole implementation difficult to follow. Ideally, I think we can get away with max two types. Also, would it make sense to turn the NoiseHandler into a pydantic model for all the checking ? It might also help in serialization. Just a suggestion.

[chMoussa]

Thanks @chMoussa. Sorry for being a pain but I think we still have too many types that makes the whole implementation difficult to follow. Ideally, I think we can get away with max two types. Also, would it make sense to turn the NoiseHandler into a pydantic model for all the checking ? It might also help in serialization. Just a suggestion.

@RolandMacDoland, I followed your suggestions. Now we only have the NoiseHandler and the classmethods are becoming mutation methods. Also for pydantic, I think I would try it in future MRs since this one is getting quite consequent.