[WIP] Add spectral mismatch model comparison table

[RDaxini]

Not ready for review.

• Partially addresses Model comparison tables #2329
• I am familiar with the contributing guidelines
• Tests added
• Updates entries in docs/sphinx/source/reference for API changes.
• Adds description and name entries in the appropriate "what's new" file in docs/sphinx/source/whatsnew for all changes. Includes link to the GitHub Issue with :issue:`num` or this Pull Request with :pull:`num`. Includes contributor name and/or GitHub username (link with :ghuser:`user`).
• New code is fully documented. Includes numpydoc compliant docstrings, examples, and comments where necessary.
• Pull request is nearly complete and ready for detailed review.
• Maintainer: Appropriate GitHub Labels (including remote-data) and Milestone are assigned to the Pull Request and linked Issue.

Build: https://pvlib-python--2353.org.readthedocs.build/en/2353/user_guide/model_comparison.html

[RDaxini]

Questions:
Should the inputs be linked to the pvlib functions that can calculate these inputs? I think it would be convenient for readers, but I also think it would a) clutter the table with long links, and b) in the case of multiple options, introduce bias if we were to select one. Overall, I lean away from linking inside the table. Thoughts? Alternatives? Maybe a list of links at the bottom, or at least a sentence or two informing users of pvlib's general capability to calculate inputs

How many cell technologies is too many to list? I think after 2 or 3, it might be best just to write "multiple"?

[cwhanse]

I don't think links to the input definitions add much value. It would be easier to read the list of inputs if the list had one input on each line, rather than a comma-separate text paragraph.

It doesn't seem very helpful when most "Cell technology" fields have a value of "Multiple". I'd use the vertical real estate to list all the cell technologies, except for 'sapm' and 'mismatch_field' which aren't specific to a cell type. The SAPM model is specific to a module product, not to a cell type.

I think "Data source" doesn't add much here. The primary use is for a modeler looking to select a model. Data used for development and validation can be relegated to the references.

[kandersolar]

@RDaxini it looks like you're thinking to create a single page to house all comparison tables, is that right?

In #2329 I was imagining these tables would live in pages dedicated to the relevant modeling topic. For example, the table in this PR would be one component of a broader page explaining pvlib's functionality related to spectrum and spectral mismatch. Similarly, the transposition model table would be in a page talking about the irradiance models. I still think that's a good approach, although of course I am interested in hearing opposing viewpoints.

[RDaxini]

@kandersolar you're too fast again, haha. I went for single page originally because we did not have subsections at that time, but I think 0be2e46 just before your comment should have fixed this in line with your suggestion. We now have one main subsection called model comparisons, and then there will be individual subsubsections explaining the functionality and comparing models. Have a look, let me know if that's what you had in mind. Or did you mean a whole subsection for "spectrum", another for "irradiance", rather than a subsection called "model comparison" (can be renamed) with subsections for those topics (spectrum, irradiance, etc.)?

[kandersolar]

Ok I see, nice. I suggest merging the Model comparisons section with the existing Modeling topics section. Also this new page's filename should be renamed to something involving "spectrum".

[RDaxini]

@kandersolar, how about 7e79344?
I left it as just "spectrum" to keep it general for now as we could potentially add more content to that page. Spectral corrections could be a single subsection on the "spectrum" page. I can fix up these details later too, I don't have any strong preference currently.

Aside, related: the user guide folder could benefit with some organization of the files, what do you think? I was considering opening a separate issue to seek opinions on categorizing those files into folders, perhaps folders aligned with the subsections perhaps... not urgent/major but the thought came to mind while working on this

[kandersolar]

I am +1 to where it's going now.

opening a separate issue to seek opinions on categorizing those files into folders, perhaps folders aligned with the subsections

+1 to this as well