[Feature Request]: Require only `pymatgen-core`

[kavanase]

Problem

Somewhat related to #1071.
Is it possible for mp-api to only require pymatgen-core, rather than the full pymatgen? Many downstream packages require code only from pymatgen, but require MPRester capabilities from mp-api, which currently requires full pymatgen.

From a quick scan through the code, it seems like there are a few places where non-core pymatgen functions are imported, so I'm not sure if this is possible or planned but it would be useful to know if so, to inform some downstream development efforts. Thanks!

Proposed Solution

...

Alternatives

No response

[kavanase]

Note from my scan for pymatgen.analysis.* (which covers most of the non-core pymatgen code – with phase_diagram, chempot_diagram and reaction_calculator being the exceptions; https://github.com/materialsproject/pymatgen-core/tree/main/src/pymatgen/analysis), the non-core code usages I see are:

• pymatgen.analysis.magnetism
• pymatgen.analysis.pourbaix_diagram.IonEntry (PourbaixDiagram and PourbaixEntry used in tests) – which I think could be easily moved to pymatgen-core as it's quite stable (& core) pymatgen code?
• pymatgen.analysis.wulff.WulffShape -- only used in tests

[JaGeo]

@kavanase It depends on emmet as well.

[kavanase]

@JaGeo yes thanks for pointing out! I added another comment but was on plane wifi so didn't go through. Emmet has a lot more non-core pymatgen dependencies, so not sure if there are any plans to pull away from non-core pymatgen there or not.

[JaGeo]

My personal opinion:

At least, I would like to keep all ChemEnv functionality in emmet. And, I don't think ChemEnv will ever be part of pymatgen-core.

[esoteric-ephemera]

Thanks for bringing this up, it's a good idea to consider given the split. Like @JaGeo said, there are some non-pymatgen-core functionalities of emmet-core that are needed, but likely only when building data (like building a ChemEnvDoc.from_structure)

Something we can look into when we have time