Feature/print value helper

[krishnavallabha]

Summary

Adds a pm.print_value() helper function as proposed in #6841.

Previously, users had to manually initialize pytensor.printing.Print
which is an unusual API. This helper wraps that op with a clean,
discoverable interface.

Usage

with pm.Model():
    x = pm.Normal("x", mu=0, sigma=1)
    x = pm.print_value(x, name="x")  # prints x during sampling

Changes

• pymc/printing.py — new print_value() helper
• pymc/__init__.py — expose as pm.print_value
• tests/test_print_value.py — tests for pass-through and naming

Closes #6841

The print_value helper is the clearest, self-contained piece to contribute from this issue. The JAX backend part lives in pytensor (a separate repo), so that would be a follow-up contribution if you want to go further.test_printing already existed so i created
test_print_value.py11:17 PMSmart move. Now let's make sure your test file is properly structured and doesn't clash with anything in the existing test_printing.py. What does the existing file test?
bash# Run this in your cloned repo to see what's already there:
cat tests/test_printing.py
Also run:
bashgrep -n "print_value|Print" tests/test_printing.py
Share the output and I'll help you make sure your test_print_value.py doesn't duplicate anything, has the right imports, and is structured to pass cleanly. Then we can get your PR opened.

[Copilot]

Pull request overview

This PR aims to add a user-facing pm.print_value() helper to wrap pytensor.printing.Print for debug-printing variable values during model evaluation/sampling, as proposed in #6841.

Changes:

• Adds a print_value() helper intended to wrap PyTensor’s Print op.
• Exposes the helper from the pymc top-level namespace as pm.print_value.
• Adds tests validating pass-through behavior and naming behavior.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 5 comments.

File	Description
printing.py	Adds a print_value() helper, but currently added at repo root rather than the pymc package module.
pymc/__init__.py	Attempts to expose print_value on the pymc namespace (currently will import-error due to module placement).
tests/test_print_value.py	Adds tests for print_value behavior and top-level accessibility.
__init__.py	Adds a repo-root __init__.py that makes the repo root a package (unexpected/undesirable).

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[Copilot]

This file is added at the repository root as printing.py, but the package module that users/tests import is pymc/printing.py (which already exists). As a result, from pymc.printing import print_value will not find this function, and the helper won’t be available as pm.print_value. Move this helper into pymc/printing.py (and export it via that module’s __all__) and remove the root-level printing.py to avoid confusion/shadowing.

[read-the-docs-community]

Documentation build overview

📚 pymc | 🛠️ Build #32019226 | 📁 Comparing 6a03ab9 against latest (0f5c0ca)

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