Add PIR (Physics Intermediate Representation) symbolic regression method

[Qazi-pk]

PIR — Physics Intermediate Representation

Classical symbolic regression engine for automated physical law discovery from data.

Method

• Monomial-basis search with log-linearization gate for power-law detection
• Pairwise structure decomposition, RANSAC, sparse regression
• Iterative residual refinement with Occam complexity penalty
• No neural components — pure classical pipeline

Blind Feynman Tier A results

12/44 EXACT blind (zero seed wobble), v3.4
Secondary: +12/44 FORM_NUMERIC (correct functional form, transcendental constant as decimal — reported separately, never summed)
Previous baseline: 7/44 (v3.3)

Files

• algorithms/PIR/regressor.py — sklearn-compatible wrapper
• algorithms/PIR/install.sh — installs from public repo (MIT license)
• algorithms/PIR/metadata.yml — method metadata
• algorithms/PIR/requirements.txt — POT (Python Optimal Transport)

Links

• Engine: https://github.com/Qazi-pk/physics-engine (public, MIT)
• Paper: https://doi.org/10.5281/zenodo.19723561

Targeting master per @gAldeia's guidance in #203.

[Qazi-pk]

12/44 EXACT blind (zero seed wobble), v3.4
Secondary: +12/44 FORM_NUMERIC (correct functional form, transcendental constant as decimal — reported separately, never summed)
Previous baseline: 7/44 (v3.3)

[Qazi-pk]

Update: The install failure is resolved.

The physics-engine package had a packaging issue (subpackages weren't being discovered by setuptools) plus some eager top-level imports pulling in optional modules that aren't needed for the regressor. I've fixed the packaging config and made the top-level imports lazy, tagged v3.4.1, and updated install.sh to point at it. A clean-room install (pip install "git+https://github.com/Qazi-pk/physics-engine.git@v3.4.1" in a fresh venv) now imports PIRRegressor successfully.

The remaining ModuleNotFoundError: No module named 'methods.pir' looks like the shared algorithms/ → methods/ harness mapping that's also failing other methods in this run (brush, eql, bsr, e2et). Happy to adjust the layout if there's a preferred structure — otherwise it appears to be on the infrastructure side. Thanks for taking the time to review.