reorganize into subpackages

[sahilpatelsp]

It might be worth considering reorganizing the library into collective subpackages rather than modules consisting of single files, which is the current approach. One such organization scheme could be the following:

qhbmlib/
  __init__.py

  ebm/
        __init__.py
        ebm.py
        energy_functions/
            kobe.py
            mlp.py
            ...
        energy_samplers/
            energy_sampler.py
            mcmc/
                mcmc.py
                energy_kernel.py
                mh.py
                gwg.py
                ...

    qnn/
        __init__.py
        qnn.py
        pqc/
            hea.py
            qcnn.py
            ...

    qhbm/
        __init__.py
        qhbm.py

    losses/
        __init__.py
        vqt.py
        qmhl.py
        ...

    metrics/
        __init__.py
        fidelity.py
        ...

    datasets/
        __init__.py
        hamiltonian.py
        ...

    utils/
        __init__.py
        utils.py

[zaqqwerty]

Can you say more about why we should reorganize in this way? You say "It might be worth considering" - why might it be worth considering?

[sahilpatelsp]

This approach would allow us to divide a single module into multiple different files rather than having a one-to-one correspondence between modules and files, which might lead to files becoming quite involved as we add new classes. It essentially decouples the user-interface of modules from the underlying file structure.

[farice]

I like the idea of e.g. from qhbmlib import losses importing the qmhl and vqt files

[zaqqwerty]

@geoffreyroeder had a comment along these lines today: since we now lean heavily on the distinction between models and inference engines, it could make sense to make model and infer be subpackages.

[zaqqwerty]

Resolved by #196