set auto for stats module

[Chirag3841]

Description
#80
This PR updates the behavior of stats.module when it is set to auto.
If numba is installed, numba will be used as the stats backend, otherwise it will fall back to base.
I also added a small test to ensure that auto resolves to either numba or base depending on whether numba is available.

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Codecov Report

❌ Patch coverage is 83.33333% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 50.00%. Comparing base (d9b64c2) to head (2dab1ea).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
src/arviz_base/rcparams.py	83.33%	1 Missing ⚠️

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Flag	BASE (d9b64c2)	HEAD (2dab1ea)
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Additional details and impacted files

@@             Coverage Diff             @@
##             main     #172       +/-   ##
===========================================
- Coverage   72.36%   50.00%   -22.37%     
===========================================
  Files          19       19               
  Lines        1918     1964       +46     
===========================================
- Hits         1388      982      -406     
- Misses        530      982      +452     

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Documentation build overview

📚 arviz-base | 🛠️ Build #31948867 | 📁 Comparing 2dab1ea against latest (2aaa4b7)

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Show files changed (28 files in total): 📝 25 modified | ➕ 0 added | ➖ 3 deleted

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tutorial/WorkingWithDataTree.html	📝 modified
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_modules/arviz_base/rcparams.html	📝 modified
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[Chirag3841]

@OriolAbril I have implemented the changes required for this PR.
Is there any need to add test case for value error too?

[OriolAbril]

this looks good but it will take a bit to merge. The numba option is not thoroughly tested yet so we should first make sure that both arviz-stats and arviz-plots continue to pass after this change.

[Chirag3841]

this looks good but it will take a bit to merge. The numba option is not thoroughly tested yet so we should first make sure that both arviz-stats and arviz-plots continue to pass after this change.

Thanks for the clarification and reviewing this PR.

[OriolAbril]

I have just tried running the arviz-stats test suite locally with these changes in default and 100 tests out of 2600 failed. We need some work on the numba backend before the change can actually be done.

[Chirag3841]

I have just tried running the arviz-stats test suite locally with these changes in default and 100 tests out of 2600 failed. We need some work on the numba backend before the change can actually be done.

@OriolAbril Got it, thanks for testing this. I’ve reverted the default back to "base" and kept the "auto" option available without enabling it by default.

[aman-coder03]

hi @OriolAbril would it be okay if I worked on fixing the numba backend issues so this change can eventually be enabled by default?
could you point me to the failing tests or the areas in the codebase that need attention? Happy to help move this forward

[OriolAbril]

could you point me to the failing tests or the areas in the codebase that need attention?

The best way to go about this is creating an arvizrc file with stats.module : numba and running the tests in arviz-stats to check the failures.

[aman-coder03]

thanks @OriolAbril! I'll set up an arvizrc file with stats.module : numba, run the arviz-stats test suite, and document the failures. I'll open a separate PR on arviz-stats once I have a clear picture of what needs fixing

[aman-coder03]

i have opened arviz-devs/arviz-stats#350 which fixes the two numba backend issues that were causing the 113 test failures
after the fix, full arviz-stats test suite passes with stats.module : numba (2632 passed, 2 skipped, 0 failed)
once that PR is merged, auto option in stats.module should work correctly