Register the overloads added by CustomDist in worker processes

[EliasRas]

Description

Currently sample_smc can fail due to a NotImplementedError if it's used with a model defined usingCustomDist. If a CustomDist is used without dist parameter, the overloads for _logprob, _logcdf and _support_point are registered only in the main process.

This PR adds an initializer which registers the overloads in the worker processes of the pool used in sample_smc.

Related Issue

• Closes BUG: pymc.sample_smc fails with pymc.CustomDist #7224
• 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://pymc--7241.org.readthedocs.build/en/7241/

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[EliasRas]

The way I'm checking if the rv is from CustomDist feels kind dirty. Is there a better way? I couldn't come up with anything better after _print_name was changed in aa679f3

[ricardoV94]

Hi @EliasRas, I'll need some time to review this one properly. Thanks for taking the initiative