Draft: Fix the bug: PrecisionMvNormalRV missing factor of 1/2 for log determinant in logp function

[olp-cs]

Description

Related Issue

• Closes BUG: PrecisionMvNormalRV missing factor of 1/2 for log determinant in logp function #7751

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--7811.org.readthedocs.build/en/7811/

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[ricardoV94]

@olp-cs there's a PR open for this, and I left a comment there about adding a regression test. The same applies here.

[asifzubair]

Hi @olp-cs , are you still working on this PR ? If not, I'd be happy to pick it up. Please let me know. 🙏

[olp-cs]

@asifzubair I've recently came back to it. However, if you don't see any updates by 11 August, feel free to take it over. Thank you!

[olp-cs]

@asifzubair

If not, I'd be happy to pick it up.

Please do; I would really appreciate it. I've reviewed test_multivariate.py but I’m not familiar enough with this part to add tests without asking a lot of questions (and taking up your time), so I’ll gladly let you handle this one and follow your commits to learn. For context, the following test was proposed in a similar PR:

If tau is a unit diagonal precision matrix the logp should match the save with the covariance logp

[asifzubair]

Sorry, @olp-cs , I should've followed up with you. Thank you for letting me tak a look at this. I left a comment on the issue. I'm not sure this fix is required. Please let me know if you disagree with my comment. I was also wondering if you ran tests after making your change and noticed that this test was failing. Thanks, again! 🙏