1341 smm model with more indices

[kilianvolmer]

Changes and Information

Please briefly list the changes (main added features, changed items, or corrected bugs) made:

• The SMM Model now works with an arbitrary number of additional AgeGroups
• Influences can come from different regions

If need be, add additional information and what the reviewer should look out for in particular:

• The code should be backwards compatible to the current implementation
• The simulation algorithm itself was not changed, the only difference there is in the function that calculates the current rates.

Merge Request - Guideline Checklist

Please check our git workflow. Use the draft feature if the Pull Request is not yet ready to review.

Checks by code author

• Every addressed issue is linked (use the "Closes #ISSUE" keyword below)
• New code adheres to coding guidelines
• No large data files have been added (files should in sum not exceed 100 KB, avoid PDFs, Word docs, etc.)
• Tests are added for new functionality and a local test run was successful (with and without OpenMP)
• Appropriate documentation within the code (Doxygen) for new functionality has been added in the code
• Appropriate external documentation (ReadTheDocs) for new functionality has been added to the online documentation
• Proper attention to licenses, especially no new third-party software with conflicting license has been added
• (For ABM development) Checked benchmark results and ran and posted a local test above from before and after development to ensure performance is monitored.

Checks by code reviewer(s)

• Corresponding issue(s) is/are linked and addressed
• Code is clean of development artifacts (no deactivated or commented code lines, no debugging printouts, etc.)
• Appropriate unit tests have been added, CI passes, code coverage and performance is acceptable (did not decrease)
• No large data files added in the whole history of commits(files should in sum not exceed 100 KB, avoid PDFs, Word docs, etc.)
• On merge, add 2-5 lines with the changes (main added features, changed items, or corrected bugs) to the merge-commit-message. This can be taken from the briefly-list-the-changes above (best case) or the separate commit messages (worst case).

Closes #1341

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.28%. Comparing base (fbaf0eb) to head (17cd0b9).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1388      +/-   ##
==========================================
- Coverage   97.28%   97.28%   -0.01%     
==========================================
  Files         175      175              
  Lines       15306    15342      +36     
==========================================
+ Hits        14891    14925      +34     
- Misses        415      417       +2     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[reneSchm]

Two comments on this:

Fixing the copyright notice is entirely out of scope of this PR. That would be fine, if the changes was limited to a file with other modifications, which is not the case. Please move the copyright changes to a new PR.

I guess gluing on the group indices works, but having to use std::apply whenever we need to index anything is frankly an awful user experience. Can you find a different solution?
Maybe replace Region by a MultiIndex template (defaulted to Region) instead? That would also avoid the usage of a nullable.

[kilianvolmer]

Two comments on this:

Fixing the copyright notice is entirely out of scope of this PR. That would be fine, if the changes was limited to a file with other modifications, which is not the case. Please move the copyright changes to a new PR.

I already moved the changes to the docs branch, that will be merged first.

I guess gluing on the group indices works, but having to use std::apply whenever we need to index anything is frankly an awful user experience. Can you find a different solution? Maybe replace Region by a MultiIndex template (defaulted to Region) instead? That would also avoid the usage of a nullable.

So far, this index is used exactly twice and I can't think of a reason to use it in the "frontend". Thus I would argue that the overhead of using this is manageable, especially as it doesn't require any other changes to existing code.