Closes two architectural-debt items from SP21 Tier 2.
T2.1 — check_early_stopping(avg_q_value) deleted entirely:
- Combined two failed mechanisms: (a) Q-value floor — not a learning
signal (high Q can mean edge OR value explosion, indistinguishable);
(b) Sharpe plateau with hardcoded `improvement < 0.01` threshold,
structurally meaningless against typical val-sharpe deltas O(1-10).
- Both subsumed by the SP21 T1.1a+T1.1b val-loss patience early-stop
with signal-driven min_delta from VAL_SHARPE_VAR_EMA.
- Legacy `old_should_stop` branch + function body deleted.
- Per feedback_no_legacy_aliases.
T2.4 — MIN_HOLD_TARGET / MIN_HOLD_PENALTY_MAX #defines deleted:
- Investigation: macros referenced ONLY in comments and the defining
line itself — no actual code use. The SP12 v3 production callers
were removed in SP20 Phase 2 Task 2.2.
- HEALTH_DIAG line at training_loop.rs:5159 updated to drop the dead
30.0/3.0 literals.
- Scope boundary: MIN_HOLD_TEMPERATURE_* chain is NOT a zombie —
actively wired (kernel producer + SP16 controller consumer).
- Per feedback_no_legacy_aliases.
T2.5 — PER hyperparams disposition (no code change):
- per_alpha=0.6, per_beta_start=0.6 are paper-canonical (Schaul et al.).
Per the SP21 plan recommendation, kept fixed for SP21. Filed for a
separate SP if later identified as a leverage point.
Affected files:
- crates/ml/src/trainers/dqn/trainer/metrics.rs:435-488
(check_early_stopping body deleted)
- crates/ml/src/trainers/dqn/trainer/training_loop.rs (7253 caller +
7291-7322 old_should_stop branch + 5159-5167 HEALTH_DIAG line)
- crates/ml/src/cuda_pipeline/state_layout.cuh:317-318
(#defines deleted)
Verification:
- cargo check -p ml --tests: passes (warnings only)
Cumulative SP21 Tier 2 status: T2.1 ✓, T2.4 ✓, T2.5 ✓ (deferred-doc).
T2.2+T1.3 (enrichment.rs constants soup, ~400 LOC) remaining.
Plan reference: docs/plans/2026-05-10-sp21-train-eval-coherence-isv-defrost.md
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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