Feature/recursive aggregation

[tburandt]

Please confirm that this PR has done the following:

• Tests Added
• Documentation Added
• Description in RELEASE_NOTES.md Added

Description of PR

This PR adds the functionality to recursively aggregating variables. Based on #385

[danielhuppmann]

Note that tests are failing because the IIASA infrastructure is unavailable today...

[danielhuppmann]

thanks @tburandt! By the way, you could have simply accepted the suggestion directly on this page, no need (any more) to copy-paste it into your editor and then commit...

Can you click "resolve" on all @stickler-ci comments that you cleaned up, please?

[tburandt]

thanks @tburandt! By the way, you could have simply accepted the suggestion directly on this page, no need (any more) to copy-paste it into your editor and then commit...

Can you click "resolve" on all @stickler-ci comments that you cleaned up, please?

Ha, ok, I wasn't actually aware of that (obviously), now I feel a bit ashamed :D

[danielhuppmann]

a few suggestions for improvements...

[danielhuppmann]

Thanks @tburandt, really nice addition to the feature list! just added a few suggestion for clean-up and adding docstrings, then good to be merged...

One question: when you use this with realistically-sized scenario data, is run-time an issue? the append() function is quite costly (because it checks that there are no duplicate rows in data)... if yes, we may want to consider a refactoring for speed (could also be implemented later)...

[tburandt]

Thanks @danielhuppmann for all your support in this PR :)

I will quickly test the feature with a larger dataset

[tburandt]

@danielhuppmann
With the current GENeSYS-MOD dataset, the time for the recursive feature is almost identical to the manual aggregation of the subcategories. After several runs with different scenarios, I couldn't observe any significant difference. However, in my original script, I also used the append-parameter for creating the final dataset for all existing subcategories.

[danielhuppmann]

took the liberty to resolve the merge conflict...

[codecov]

Codecov Report

Merging #405 into master will increase coverage by 0.01%.
The diff coverage is 95.23%.

@@            Coverage Diff             @@
##           master     #405      +/-   ##
==========================================
+ Coverage   93.25%   93.26%   +0.01%     
==========================================
  Files          35       35              
  Lines        4090     4129      +39     
==========================================
+ Hits         3814     3851      +37     
- Misses        276      278       +2     

Impacted Files	Coverage Δ
pyam/core.py	92.14% <71.42%> (-0.22%)	⬇️
pyam/_aggregate.py	96.52% <100.00%> (+0.68%)	⬆️
tests/test_feature_aggregate.py	100.00% <100.00%> (ø)

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[danielhuppmann]

thank you @tburandt! let's keep in mind that this feature could probably be faster - so let's revisit it and refactor the code when aggregating the results takes longer than running the model...