Support PyTensor deterministic operations as observations

[wd60622]

Description

Will need some help on this implementation and how to best test this.

Related Issue

• Closes BUG: data as observed in RV #7649
• 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):

---

📚 Documentation preview 📚: https://pymc--7656.org.readthedocs.build/en/7656/

[ricardoV94]

We need to tell InferenceData converter how to get the data values to put in constant_data, and observed_data. It had some hardcode logic assuming you could only due Casts

[ricardoV94]

I don't consider this a bugfix, it's behavior that was explicitly forbidden for conservative reasons (more like a NotImplementedError)

[wd60622]

We need to tell InferenceData converter how to get the data values to put in constant_data, and observed_data. It had some hardcode logic assuming you could only due Casts

Where does this happen in the code?

[wd60622]

I think the MiniBatch tests will still fail. Any thoughts on how that should behave?

[wd60622]

Also, feel free to choose a better title! I couldn't express it too well

[wd60622]

Should I sample this to check that it has the correct data in the InferenceData?

[ricardoV94]

No, we have more direct ways of testing it

[ricardoV94]

We need to tell InferenceData converter how to get the data values to put in constant_data, and observed_data. It had some hardcode logic assuming you could only due Casts

Where does this happen in the code?

pymc/pymc/backends/arviz.py

Line 63 in fa43eba

obs_data = extract_obs_data(aux_obs)

pymc/pymc/pytensorf.py

Line 152 in fa43eba

def extract_obs_data(x: TensorVariable) -> np.ndarray:

We should be able to just use constant_fold (also in pytensor) for it

[wd60622]

We should be able to just use constant_fold (also in pytensor) for it

I have an implementation before this suggestion. I need a little help understanding this. Feel free to put suggestion

[ricardoV94]

We should be able to just use constant_fold (also in pytensor) for it

I have an implementation before this suggestion. I need a little help understanding this. Feel free to put suggestion

What do you mean? My suggestion is to simply call constant_fold on the observed variable