Add pre-fitted atomic Gaussian parameter loader and data

[Ao-chuba]

2nd PR for Improvement of the robustness of poisson equation

This pull request implements a zero dependency loader load_atomic_gaussian_params(element) in src/grid/coulomb.py to retrieve pre-fitted $s$-type Gaussian parameters (coefficients and exponents) for elements H, C, N, O, and Cl from a package-safe JSON dataset (atomic_gauss_params.json). The loader supports case insensitive, space stripped element symbols (e.g. "cl", " C ") as well as atomic numbers (e.g. 17), utilizing a module-level lazy cache to avoid repeated disk reads. The packaging configuration in MANIFEST.in has been updated to bundle the dataset, the loader has been exported at the package root level, and unit tests have been added to verify type handling, lookup correctness, and parameter validity.

related to issue -> here

[Copilot]

Pull request overview

This PR adds a package-safe, zero-extra-dependency loader to fetch pre-fitted s-type atomic Gaussian parameters (coefficients/exponents) for a small set of elements (H, C, N, O, Cl), backed by a JSON dataset shipped with the package. This supports the Poisson-solver robustness effort by enabling “promolecular/fit-based” strategies without external fit libraries.

Changes:

• Added load_atomic_gaussian_params(element) with symbol/atomic-number support and lazy JSON caching.
• Added src/grid/data/atomic_gauss_params.json containing the fitted parameters.
• Exported the loader and added unit tests validating basic lookup/shape/value constraints.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/grid/coulomb.py	Implements the JSON-backed atomic parameter loader and exports it.
src/grid/data/atomic_gauss_params.json	Adds the pre-fitted parameter dataset for supported elements.
src/grid/tests/test_coulomb.py	Adds tests for the new loader.
src/grid/__init__.py	Re-exports Coulomb module symbols at package root.
MANIFEST.in	Attempts to include the new JSON dataset in packaged artifacts.

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[marco-2023]

These are weak tests, but for now, fine

[Ao-chuba]

RIght i see, i think to improve the tc , we can add in normalization checks or potential accuracy checks ? if that makes sense we can add in those test cases in the next commit or maybe even a different pr.

[marco-2023]

Please fix the comments, also check #317 for the Manifest.in structure

[Ao-chuba]

@marco-2023 thanks for the review, i have updated the pr as requested. please do let me know if any other is required.

[Copilot]

Pull request overview

Copilot reviewed 5 out of 6 changed files in this pull request and generated 5 comments.

[Ao-chuba]

@marco-2023

i think its suppose to be

include README.md
include LICENSE
recursive-include src/grid/data *.json *.npz
global-exclude *.pyc pycache .DS_Store

since directory is in src->grid->data . also this pr deals with new json. so need to include json too.

[Ao-chuba]

@marco-2023 I have fixed the spacing suggested ,(removal of white spaces). about the last suggestion i am confused since , depsite it seeming like a high stake issue, everything seem to work as it is .

[marco-2023]

I think it is ok now.

[marco-2023]

@marco-2023 I have fixed the spacing suggested ,(removal of white spaces). about the last suggestion i am confused since, despite it seeming like a high-stakes issue, everything seem to work as it is .

Hi Aochuba, these suggestions are made to maintain the quality of the codebase. After you make your changes, you should lint the changed files using black: black -l 100 <file>. This will prevent this kind of issue in the future. I approved this PR. Feel free to merge it.

[Ao-chuba]

@marco-2023 I have fixed the spacing suggested ,(removal of white spaces). about the last suggestion i am confused since, despite it seeming like a high-stakes issue, everything seem to work as it is .

Hi Aochuba, these suggestions are made to maintain the quality of the codebase. After you make your changes, you should lint the changed files using black: black -l 100 <file>. This will prevent this kind of issue in the future. I approved this PR. Feel free to merge it.

thank you for the approval @marco-2023 , Since I don't have merge access to the repo, could you please merge it.