implemented MAD using scipy

[Ayush-Devs]

PR Description:

this PR closes #149.
median_abs_deviation from scipy.stats is used to compute the MAD.

Merge Checklist

• the PR has been reviewed and all comments are resolved
• all [CI][what-is-ci] checks pass
• (if applicable): the PR description includes the phrase closes #<issue-number> to [automatically close an issue][auto-close-documentation]
• (if applicable): bug fixes, new features, or [API][what-is-api] changes are documented in [whats_new.rst][whats-new-file]
• (if applicable): new contributors have added themselves to the authors list in the CITATION.cff file

[sappelhoff]

Thanks for the changes, but the idea would be to replace our custom function _mad with the scipy implementation, instead of just calling the scipy function from within _mad. Would you be up for implementing this?

[Ayush-Devs]

just confirming before making the changes, you want me to remove the _mad function and directly implement scipy in the areas _mad function is called. Am I going in the right direction?

[sappelhoff]

yes, and resolving this issue would also mean checking that the tests all still pass, and that _mad is adequately and fully replaced everywhere.

[Ayush-Devs]

The custom implementation of _mad raised a value error when the input was not in 1D or 2D. Test_utils is expecting a value error that is not thrown by scipy.stats.median_abs_deviation. How do you really want me to fix this issue?

1. Remove the test that expects the value error:
   from test_utils.py line 166
   //Test exception with > 2-D arrays
   tst = np.random.rand(3, 3, 3)
   with pytest.raises(ValueError):
   median_abs_deviation(tst, axis=0)

2. create a custom function (i already did that in my first commit)

3. check the dimensions before the function is called.

i don't really understand the consequences of omitting this check for 3d arrays. please tell me how to proceed

[sappelhoff]

I think we could also leave the changes as they are. But the current test suite needs to pass.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.39%. Comparing base (82390ac) to head (5cd26a5).
Report is 21 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #153      +/-   ##
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- Coverage   99.39%   99.39%   -0.01%     
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  Files          14       14              
  Lines        1315     1313       -2     
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- Hits         1307     1305       -2     
  Misses          8        8              

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[sappelhoff]

Great, thanks @Ayush-Devs could you please:

1. add a changelog entry
2. add yourself to the CITATION.cff file

Then we can merge this.

[Ayush-Devs]

I really hope I correctly updated the citation and changelog files. thank you so much for guiding me through this experience.

[sappelhoff]

Thanks @Ayush-Devs 🥳