Add scipy-like kn helper

[Aarsh-Wankar]

I added an additional function kn in the pytensor/tensor/math.py file which just calls kv function under the hood. This is to provide functionality similar to that offered by scipy.special.kn.

Description

scipy has two functions for computing modified Bessel functions of the second kind: scipy.special.kv (which works for functions of real order) and scipy.special.kn (which works for functions of integer order). pytensor has a function pytensor.tensor.kv which is similar to scipy, but it lacks a kn counterpart. Thus I added an extra helper function kn which just calls kv under the hood, as kv also works for integers.

Related Issue

• Closes Add helper for special.kn that just calls special.kv under the hood #1308
• Related to #

Checklist

• Checked that the pre-commit linting/style checks pass
• Included tests that prove the fix is effective or that the new feature works
• Added necessary documentation (docstrings and/or example notebooks)
• If you are a pro: each commit corresponds to a relevant logical change

Type of change

• New feature / enhancement
• Bug fix
• Documentation
• Maintenance
• Other (please specify):

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📚 Documentation preview 📚: https://pytensor--1313.org.readthedocs.build/en/1313/

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 81.99%. Comparing base (b75c18f) to head (6e1a99c).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1313   +/-   ##
=======================================
  Coverage   81.99%   81.99%           
=======================================
  Files         188      188           
  Lines       48506    48508    +2     
  Branches     8672     8672           
=======================================
+ Hits        39771    39773    +2     
  Misses       6583     6583           
  Partials     2152     2152           

Files with missing lines	Coverage Δ
pytensor/tensor/math.py	92.97% <100.00%> (+0.01%)	⬆️

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[ricardoV94]

Thanks @Aarsh-Wankar