DynamisLab/src/SR_analysis

SR analysis

Authority and scope

This directory is the frozen symbolic-regression evidence package for the LegacyCelerisLab fluidic pinball. The active scientific scope is Kármán-cloak and Illusion PPO data collection, symbolic discovery/refit, closed-loop CFD validation, sampled duration/generalization extensions, term deletion/scaling, and canonical publication export. The disturbance-free steady scene remains only as the calibration used to interpret the Kármán rear constant.

The authoritative evidence index is results/README.md; execution details are in PIPELINE.md. Material under archive/ is historical, excluded, or non-authoritative.

Three-stage workflow

1. stage_1_infer.py: collect immutable, run-scoped Legacy PPO trajectories for trained Kármán and Illusion scenes.
2. stage_2_fit.py: perform broad per-case discovery, within-objective joint discovery, and fixed-topology all-data coefficient refit.
3. stage_3_validate.py: deploy PPO, symbolic, uncontrolled, or constant policies in serial Legacy CFD and evaluate the exact legacy DTW contract.

The acceptance chain is data and wiring checks → offline discovery/Pareto diagnostics → frozen topology and coefficient refit → finite closed-loop CFD → 200-step acceptance → 400-step duration and sampled unseen-condition checks → term deletion/scaling. Offline R² helps discover structure; it does not accept a controller. Averages never override a non-finite or prematurely terminated case.

Scientific contracts

• Solver/model/norm: Stage 1 and Stage 3 use LegacyCelerisLab and the frozen legacy PPO models. Runtime PPO observations use the scene's frozen data/karman/**/norm.json or data/illusion/**/norm.json; PPO inference defaults to CPU while PyCUDA owns the CFD GPU.
• Native order: bodies/actions are front, upper, lower; forces are front, upper, lower with (x,y) components; sensors are upper, centre, lower with (u_x,u_y) components. checks/order_contract.py is the runtime gate.
• Causal alignment: Stage 2 uses causal_post_state_to_next_action: recorded post-state i predicts action i+1. Warm-up and lag construction are trajectory-local and splits do not cross trajectories.
• Action units: formulas output alpha = omega/U0. PPO normalized actions are decoded with the scene scale and bias before fitting; Stage 3 converts formula outputs back to omega for CFD.
• Mapped-shared deployment: the canonical architecture is alpha_F=(h_F(x)-h_F(Gx))/2, alpha_U=h_R(x), alpha_L=-h_R(Gx). This imposes exact reflection symmetry; it is not a claim that PPO training was equivariant. Three independent heads are diagnostic only.
• Metric: legacy_dtw_v1_abs_n_unclipped, reported as legacy_reference_cycle_vs_last_recorded_cycle, is the exact acceptance metric. Its fitted circular lag is part of the historical comparison algorithm, not a physical delay.
• Names: Kármán scene re_code uses reference length 2D, so Re_D=re_code/2. Illusion labels such as 1L are historical: the stored target_diameter value is passed to add_cylinder as a radius and must not be silently relabelled as a physical diameter.

Current claim and evidence chain

Accepted training data are data/runs/article-joint-data-karman-20260718 (Re-code 50/100/200/400) and data/runs/article-joint-data-illusion-20260718 (0.75L/1L/1.5L). Formula discovery, refits, accepted and rejected CFD, 400-step duration, sampled unseen points, deletion/scaling, steady calibration, and plotting are retained under results/runs/article-* and results/runs/article2-* because their manifests and parent paths are provenance dependencies.

The Kármán evidence supports a controller dominated by persistent rear counter-rotation, with secondary rear-lift feedback and weak tested front feedback. The steady sweep calibrates the rear constant's magnitude; it is not a third fitting objective. The Illusion result is a finite symmetric numerical family, but its terms are partly replaceable and it does not establish explicit target tracking. Neither result proves global symbolic optimality, causal flow mechanism, universal high-Re behavior, or distribution-wide generalization; Article2 supports only the explicitly sampled conditions.

Active package map

• Root: configs.py, the three stages, this README, and PIPELINE.md.
• checks/: order and policy-replay gates.
• utils/: active data, feature, symmetry, metric, formula, CFD, and provenance contracts.
• tools/: canonical plotting/export tools (prepare_plotting_data.py, telemetry_to_csv.py, both SR plotting modules, and export_flow_comparison.py).
• tests/: CPU contract tests.
• data/: frozen Kármán/Illusion norms, steady calibration data, and the two accepted article data runs.
• results/: the evidence index and provenance-dependent article-*/article2-* families.
• archive/: excluded experiments, diagnostics, old run families, superseded flat surfaces, and historical code/docs. Archive paths may be non-executable.

Verification

From the repository root:

PYTHONPATH=src conda run -n sr_env python -m pytest src/SR_analysis/tests -q
python3 -m compileall -q src/SR_analysis/configs.py src/SR_analysis/stage_1_infer.py src/SR_analysis/stage_2_fit.py src/SR_analysis/stage_3_validate.py src/SR_analysis/utils src/SR_analysis/checks src/SR_analysis/tools
git diff --check -- src/SR_analysis

No GPU CFD is part of this verification.